From 54f7338fa119802cabb12f7fc0020a167d9690c0 Mon Sep 17 00:00:00 2001
From: Bruce Momjian <bruce@momjian.us>
Date: Thu, 27 Mar 2003 16:51:29 +0000
Subject: [PATCH] This patch implements holdable cursors, following the
proposal (materialization into a tuple store) discussed on pgsql-hackers
earlier. I've updated the documentation and the regression tests.
Notes on the implementation:
- I needed to change the tuple store API slightly -- it assumes that it
won't be used to hold data across transaction boundaries, so the temp
files that it uses for on-disk storage are automatically reclaimed at
end-of-transaction. I added a flag to tuplestore_begin_heap() to control
this behavior. Is changing the tuple store API in this fashion OK?
- in order to store executor results in a tuple store, I added a new
CommandDest. This works well for the most part, with one exception: the
current DestFunction API doesn't provide enough information to allow the
Executor to store results into an arbitrary tuple store (where the
particular tuple store to use is chosen by the call site of
ExecutorRun). To workaround this, I've temporarily hacked up a solution
that works, but is not ideal: since the receiveTuple DestFunction is
passed the portal name, we can use that to lookup the Portal data
structure for the cursor and then use that to get at the tuple store the
Portal is using. This unnecessarily ties the Portal code with the
tupleReceiver code, but it works...
The proper fix for this is probably to change the DestFunction API --
Tom suggested passing the full QueryDesc to the receiveTuple function.
In that case, callers of ExecutorRun could "subclass" QueryDesc to add
any additional fields that their particular CommandDest needed to get
access to. This approach would work, but I'd like to think about it for
a little bit longer before deciding which route to go. In the mean time,
the code works fine, so I don't think a fix is urgent.
- (semi-related) I added a NO SCROLL keyword to DECLARE CURSOR, and
adjusted the behavior of SCROLL in accordance with the discussion on
-hackers.
- (unrelated) Cleaned up some SGML markup in sql.sgml, copy.sgml
Neil Conway
---
contrib/tablefunc/tablefunc.c | 4 +-
doc/src/sgml/ref/copy.sgml | 16 +-
doc/src/sgml/ref/declare.sgml | 137 ++++++++++----
doc/src/sgml/ref/fetch.sgml | 53 +++---
doc/src/sgml/ref/move.sgml | 10 +-
doc/src/sgml/sql.sgml | 106 ++++++-----
src/backend/access/transam/xact.c | 6 +-
src/backend/commands/copy.c | 10 +-
src/backend/commands/portalcmds.c | 262 +++++++++++++++++++++++---
src/backend/executor/Makefile | 4 +-
src/backend/executor/execMain.c | 15 +-
src/backend/executor/execQual.c | 5 +-
src/backend/executor/nodeHash.c | 4 +-
src/backend/executor/nodeHashjoin.c | 4 +-
src/backend/executor/nodeMaterial.c | 5 +-
src/backend/executor/spi.c | 4 +-
src/backend/parser/analyze.c | 9 +-
src/backend/parser/gram.y | 21 ++-
src/backend/parser/keywords.c | 3 +-
src/backend/storage/file/buffile.c | 10 +-
src/backend/storage/file/fd.c | 25 ++-
src/backend/tcop/dest.c | 11 +-
src/backend/utils/mmgr/mcxt.c | 5 +-
src/backend/utils/mmgr/portalmem.c | 116 +++++++++---
src/backend/utils/sort/logtape.c | 4 +-
src/backend/utils/sort/tuplestore.c | 32 +++-
src/include/nodes/parsenodes.h | 6 +-
src/include/storage/buffile.h | 4 +-
src/include/storage/fd.h | 4 +-
src/include/tcop/dest.h | 5 +-
src/include/utils/portal.h | 39 +++-
src/include/utils/tuplestore.h | 5 +-
src/pl/plpgsql/src/pl_exec.c | 4 +-
src/test/regress/expected/portals.out | 112 ++++++++---
src/test/regress/sql/portals.sql | 100 +++++++---
35 files changed, 848 insertions(+), 312 deletions(-)
diff --git a/contrib/tablefunc/tablefunc.c b/contrib/tablefunc/tablefunc.c
index 735e889dbdb..81f68119f89 100644
--- a/contrib/tablefunc/tablefunc.c
+++ b/contrib/tablefunc/tablefunc.c
@@ -853,7 +853,7 @@ get_crosstab_tuplestore(char *sql,
MemoryContext SPIcontext;
/* initialize our tuplestore */
- tupstore = tuplestore_begin_heap(true, SortMem);
+ tupstore = tuplestore_begin_heap(true, false, SortMem);
/* Connect to SPI manager */
if ((ret = SPI_connect()) < 0)
@@ -1124,7 +1124,7 @@ connectby(char *relname,
oldcontext = MemoryContextSwitchTo(per_query_ctx);
/* initialize our tuplestore */
- tupstore = tuplestore_begin_heap(true, SortMem);
+ tupstore = tuplestore_begin_heap(true, false, SortMem);
MemoryContextSwitchTo(oldcontext);
diff --git a/doc/src/sgml/ref/copy.sgml b/doc/src/sgml/ref/copy.sgml
index 8aa5b90a9ed..389b455fde7 100644
--- a/doc/src/sgml/ref/copy.sgml
+++ b/doc/src/sgml/ref/copy.sgml
@@ -1,5 +1,5 @@
<!--
-$Header: /cvsroot/pgsql/doc/src/sgml/ref/copy.sgml,v 1.40 2002/09/21 18:32:54 petere Exp $
+$Header: /cvsroot/pgsql/doc/src/sgml/ref/copy.sgml,v 1.41 2003/03/27 16:51:27 momjian Exp $
PostgreSQL documentation
-->
@@ -133,9 +133,10 @@ COPY <replaceable class="parameter">table</replaceable> [ ( <replaceable class="
</para>
<note>
<para>
- On a copy in, any data item that matches this string will be stored as
- a NULL value, so you should make sure that you use the same string
- as you used on copy out.
+ On a <command>COPY FROM</command>, any data item that matches
+ this string will be stored as a NULL value, so you should
+ make sure that you use the same string as you used with
+ <command>COPY TO</command>.
</para>
</note>
</listitem>
@@ -210,7 +211,8 @@ ERROR: <replaceable>reason</replaceable>
or write to a file. The file must be accessible to the backend and
the name must be specified from the viewpoint of the backend. When
<filename>stdin</filename> or <filename>stdout</filename> is
- specified, data flows through the client frontend to the backend.
+ specified, data is transmitted via the connection between the
+ client frontend and the backend.
<tip>
<para>
@@ -234,8 +236,8 @@ ERROR: <replaceable>reason</replaceable>
Notes
</title>
<para>
- <command>COPY</command> can only be used with plain tables, not with
- views.
+ <command>COPY</command> can only be used with plain tables, not
+ with views.
</para>
<para>
diff --git a/doc/src/sgml/ref/declare.sgml b/doc/src/sgml/ref/declare.sgml
index 2801aeeabb2..f0673c44b67 100644
--- a/doc/src/sgml/ref/declare.sgml
+++ b/doc/src/sgml/ref/declare.sgml
@@ -1,5 +1,5 @@
<!--
-$Header: /cvsroot/pgsql/doc/src/sgml/ref/declare.sgml,v 1.20 2003/03/21 17:11:46 momjian Exp $
+$Header: /cvsroot/pgsql/doc/src/sgml/ref/declare.sgml,v 1.21 2003/03/27 16:51:27 momjian Exp $
PostgreSQL documentation
-->
@@ -21,8 +21,8 @@ PostgreSQL documentation
<date>1999-07-20</date>
</refsynopsisdivinfo>
<synopsis>
-DECLARE <replaceable class="parameter">cursorname</replaceable> [ BINARY ] [ INSENSITIVE ] [ SCROLL ]
- CURSOR FOR <replaceable class="parameter">query</replaceable>
+DECLARE <replaceable class="parameter">cursorname</replaceable> [ BINARY ] [ INSENSITIVE ] [ [ NO ] SCROLL ]
+ CURSOR [ { WITH | WITHOUT } HOLD ] FOR <replaceable class="parameter">query</replaceable>
[ FOR { READ ONLY | UPDATE [ OF <replaceable class="parameter">column</replaceable> [, ...] ] ]
</synopsis>
<refsect2 id="R2-SQL-DECLARE-1">
@@ -38,7 +38,8 @@ DECLARE <replaceable class="parameter">cursorname</replaceable> [ BINARY ] [ INS
<term><replaceable class="parameter">cursorname</replaceable></term>
<listitem>
<para>
- The name of the cursor to be used in subsequent FETCH operations.
+ The name of the cursor to be used in subsequent
+ <command>FETCH</command> operations.
</para>
</listitem>
</varlistentry>
@@ -57,8 +58,20 @@ DECLARE <replaceable class="parameter">cursorname</replaceable> [ BINARY ] [ INS
<listitem>
<para>
<acronym>SQL92</acronym> keyword indicating that data retrieved
- from the cursor should be unaffected by updates from other processes or cursors.
- By default, all cursors are insensitive. This keyword has no effect.
+ from the cursor should be unaffected by updates from other
+ processes or cursors. By default, all cursors are insensitive.
+ This keyword currently has no effect and is present for
+ compatibility with the SQL standard.
+ </para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term>NO SCROLL</term>
+ <listitem>
+ <para>
+ Specifies that the cursor cannot be used to retrieve rows in a
+ nonsequential fashion (e.g., backward).
</para>
</listitem>
</varlistentry>
@@ -67,8 +80,33 @@ DECLARE <replaceable class="parameter">cursorname</replaceable> [ BINARY ] [ INS
<term>SCROLL</term>
<listitem>
<para>
- Specifies that the cursor may be used to retrieve rows
- in a nonsequential fashion (e.g., backwards).
+ Specifies that the cursor may be used to retrieve rows in a
+ nonsequential fashion (e.g., backward). Depending upon the
+ complexity of the query's execution plan, specifying
+ <literal>SCROLL</literal> may impose a slight performance penalty
+ on the query's execution time.
+ </para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term>WITHOUT HOLD</term>
+ <listitem>
+ <para>
+ Specifies that the cursor cannot be used outside of the
+ transaction that created it. If neither <literal>WITHOUT
+ HOLD</literal> nor <literal>WITH HOLD</literal> is specified,
+ <literal>WITH HOLD</literal> is the default.
+ </para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term>WITH HOLD</term>
+ <listitem>
+ <para>
+ Specifies that the cursor may be used after the transaction
+ that creates it successfully commits.
</para>
</listitem>
</varlistentry>
@@ -124,7 +162,8 @@ DECLARE <replaceable class="parameter">cursorname</replaceable> [ BINARY ] [ INS
</para>
<para>
- The BINARY, INSENSITIVE, and SCROLL keywords may appear in any order.
+ The <literal>BINARY</literal>, <literal>INSENSITIVE</literal>,
+ <literal>SCROLL</literal> keywords may appear in any order.
</para>
</refsect2>
@@ -144,7 +183,7 @@ DECLARE CURSOR
</computeroutput></term>
<listitem>
<para>
- The message returned if the SELECT is run successfully.
+ The message returned if the <command>SELECT</command> is run successfully.
</para>
</listitem>
</varlistentry>
@@ -155,9 +194,8 @@ WARNING: Closing pre-existing portal "<replaceable class="parameter">cursorname
</computeroutput></term>
<listitem>
<para>
- This message is reported if the same cursor name was already declared
- in the current transaction block. The previous definition is
- discarded.
+ This message is reported if a cursor with the same name already
+ exists. The previous definition is discarded.
</para>
</listitem>
</varlistentry>
@@ -168,7 +206,9 @@ ERROR: DECLARE CURSOR may only be used in begin/end transaction blocks
</computeroutput></term>
<listitem>
<para>
- This error occurs if the cursor is not declared within a transaction block.
+ This error occurs if the cursor is not declared within a
+ transaction block, and <literal>WITH HOLD</literal> is not
+ specified.
</para>
</listitem>
</varlistentry>
@@ -193,16 +233,14 @@ ERROR: DECLARE CURSOR may only be used in begin/end transaction blocks
</para>
<para>
- Normal cursors return data in text format, the same as a <command>SELECT</>
- would produce. Since
- data is stored natively in binary format, the system must
- do a conversion to produce the text format. In addition,
- text formats are often larger in size than the corresponding binary format.
- Once the information comes back in text form, the client
- application may need to convert it to a binary format to
- manipulate it.
- BINARY cursors give you back the data in the native binary
- representation.
+ Normal cursors return data in text format, the same as a
+ <command>SELECT</> would produce. Since data is stored natively in
+ binary format, the system must do a conversion to produce the text
+ format. In addition, text formats are often larger in size than the
+ corresponding binary format. Once the information comes back in
+ text form, the client application may need to convert it to a
+ binary format to manipulate it. BINARY cursors give you back the
+ data in the native binary representation.
</para>
<para>
@@ -245,7 +283,9 @@ ERROR: DECLARE CURSOR may only be used in begin/end transaction blocks
</title>
<para>
- Cursors are only available within transactions. Use
+ If <literal>WITH HOLD</literal> is not specified, the cursor
+ created by this command can only be used within the current
+ transaction. Use
<xref linkend="sql-begin" endterm="sql-begin-title">,
<xref linkend="sql-commit" endterm="sql-commit-title">
and
@@ -254,12 +294,25 @@ ERROR: DECLARE CURSOR may only be used in begin/end transaction blocks
</para>
<para>
- The <literal>SCROLL</> option should be specified when defining a cursor
- that will be used to fetch backwards. This is required by
- <acronym>SQL92</acronym>. However, for compatibility with
- earlier versions, <productname>PostgreSQL</productname> will allow
- backward fetches without <literal>SCROLL</>, if the cursor's query plan
- is simple enough that no extra overhead is needed to support it.
+ If <literal>WITH HOLD</literal> is specified and the transaction
+ that created the cursor successfully commits, the cursor can be
+ accessed outside the creating transaction. If the creating
+ transaction is aborted, the cursor is removed. A cursor created
+ with <literal>WITH HOLD</literal> is closed when an explicit
+ <command>CLOSE</command> command is issued on it, or the client
+ connection is terminated.
+ </para>
+
+ <para>
+ The <literal>SCROLL</> option should be specified when defining a
+ cursor that will be used to fetch backwards. This is required by
+ <acronym>SQL92</acronym>. However, for compatibility with earlier
+ versions, <productname>PostgreSQL</productname> will allow
+ backward fetches without <literal>SCROLL</>, if the cursor's query
+ plan is simple enough that no extra overhead is needed to support
+ it. However, application developers are advised not to rely on
+ using backward fetches from a cursor that has not been created
+ with <literal>SCROLL</literal>.
</para>
<para>
@@ -271,7 +324,7 @@ ERROR: DECLARE CURSOR may only be used in begin/end transaction blocks
However, <application>ecpg</application>, the
embedded SQL preprocessor for <productname>PostgreSQL</productname>,
supports the <acronym>SQL92</acronym> cursor conventions, including those
- involving DECLARE and OPEN statements.
+ involving <command>DECLARE</command> and <command>OPEN</command> statements.
</para>
</refsect2>
</refsect1>
@@ -303,13 +356,21 @@ DECLARE liahona CURSOR
SQL92
</title>
<para>
- <acronym>SQL92</acronym> allows cursors only in embedded <acronym>SQL</acronym>
- and in modules. <productname>PostgreSQL</productname> permits cursors to be used
- interactively.
+ <para>
+ <acronym>SQL92</acronym> allows cursors only in embedded
+ <acronym>SQL</acronym> and in modules. <productname>PostgreSQL</>
+ permits cursors to be used interactively.
+ </para>
+
+ <para>
<acronym>SQL92</acronym> allows embedded or modular cursors to
- update database information.
- All <productname>PostgreSQL</productname> cursors are read only.
- The BINARY keyword is a <productname>PostgreSQL</productname> extension.
+ update database information. All <productname>PostgreSQL</>
+ cursors are read only.
+ </para>
+
+ <para>
+ The <literal>BINARY</literal> keyword is a
+ <productname>PostgreSQL</productname> extension.
</para>
</refsect2>
</refsect1>
diff --git a/doc/src/sgml/ref/fetch.sgml b/doc/src/sgml/ref/fetch.sgml
index 8f3244eb39f..a1f3b13719f 100644
--- a/doc/src/sgml/ref/fetch.sgml
+++ b/doc/src/sgml/ref/fetch.sgml
@@ -1,5 +1,5 @@
<!--
-$Header: /cvsroot/pgsql/doc/src/sgml/ref/fetch.sgml,v 1.27 2003/03/11 19:40:22 tgl Exp $
+$Header: /cvsroot/pgsql/doc/src/sgml/ref/fetch.sgml,v 1.28 2003/03/27 16:51:27 momjian Exp $
PostgreSQL documentation
-->
@@ -251,8 +251,7 @@ WARNING: PerformPortalFetch: portal "<replaceable class="PARAMETER">cursor</rep
</computeroutput></term>
<listitem>
<para>
- If <replaceable class="PARAMETER">cursor</replaceable> is not known.
- The cursor must have been declared within the current transaction block.
+ There is no cursor with the specified name.
</para>
</listitem>
</varlistentry>
@@ -326,7 +325,9 @@ WARNING: PerformPortalFetch: portal "<replaceable class="PARAMETER">cursor</rep
use any variants of <command>FETCH</> other than <command>FETCH NEXT</>
or <command>FETCH FORWARD</> with a positive count. For simple queries
<productname>PostgreSQL</productname> will allow backwards fetch from
- cursors not declared with SCROLL, but this behavior is best not relied on.
+ cursors not declared with SCROLL, but this behavior is best not
+ relied on. If the cursor is declared with NO SCROLL, no backward
+ fetches are allowed.
</para>
<para>
@@ -339,16 +340,11 @@ WARNING: PerformPortalFetch: portal "<replaceable class="PARAMETER">cursor</rep
</para>
<para>
- Updating data via a cursor is not supported by
- <productname>PostgreSQL</productname>,
- because mapping cursor updates back to base tables is
- not generally possible, as is also the case with VIEW updates.
- Consequently,
- users must issue explicit UPDATE commands to replace data.
- </para>
-
- <para>
- Cursors may only be used inside transaction blocks.
+ Updating data via a cursor is not supported by
+ <productname>PostgreSQL</productname>, because mapping cursor
+ updates back to base tables is not generally possible, as is also
+ the case with view updates. Consequently, users must issue
+ explicit <command>UPDATE</command> commands to replace data.
</para>
<para>
@@ -357,12 +353,6 @@ WARNING: PerformPortalFetch: portal "<replaceable class="PARAMETER">cursor</rep
Use
<xref linkend="sql-move" endterm="sql-move-title">
to change cursor position without retrieving data.
- Refer to
- <xref linkend="sql-begin" endterm="sql-begin-title">,
- <xref linkend="sql-commit" endterm="sql-commit-title">,
- and
- <xref linkend="sql-rollback" endterm="sql-rollback-title">
- for further information about transactions.
</para>
</refsect2>
</refsect1>
@@ -379,7 +369,7 @@ WARNING: PerformPortalFetch: portal "<replaceable class="PARAMETER">cursor</rep
-- Set up and use a cursor:
BEGIN WORK;
-DECLARE liahona CURSOR FOR SELECT * FROM films;
+DECLARE liahona SCROLL CURSOR FOR SELECT * FROM films;
-- Fetch first 5 rows in the cursor liahona:
FETCH FORWARD 5 IN liahona;
@@ -425,9 +415,10 @@ COMMIT WORK;
</title>
<para>
- <acronym>SQL92</acronym> defines FETCH for use in embedded contexts only.
- Therefore, it describes placing the results into explicit variables using
- an <literal>INTO</> clause, for example:
+ <acronym>SQL92</acronym> defines <command>FETCH</command> for use
+ in embedded contexts only. Therefore, it describes placing the
+ results into explicit variables using an <literal>INTO</> clause,
+ for example:
<synopsis>
FETCH ABSOLUTE <replaceable class="PARAMETER">n</replaceable>
@@ -435,16 +426,18 @@ FETCH ABSOLUTE <replaceable class="PARAMETER">n</replaceable>
INTO :<replaceable class="PARAMETER">variable</replaceable> [, ...]
</synopsis>
- <productname>PostgreSQL</productname>'s use of non-embedded cursors
- is non-standard, and so is its practice of returning the result data
- as if it were a SELECT result. Other than this point, FETCH is fully
+ <productname>PostgreSQL</productname>'s use of non-embedded
+ cursors is non-standard, and so is its practice of returning the
+ result data as if it were a <command>SELECT</command> result.
+ Other than this point, <command>FETCH</command> is fully
upward-compatible with <acronym>SQL92</acronym>.
</para>
<para>
- The FETCH forms involving FORWARD and BACKWARD (including the forms
- FETCH <replaceable class="PARAMETER">count</replaceable> and FETCH ALL,
- in which FORWARD is implicit) are <productname>PostgreSQL</productname>
+ The <command>FETCH</command> forms involving FORWARD and BACKWARD
+ (including the forms FETCH <replaceable
+ class="PARAMETER">count</replaceable> and FETCH ALL, in which
+ FORWARD is implicit) are <productname>PostgreSQL</productname>
extensions.
</para>
diff --git a/doc/src/sgml/ref/move.sgml b/doc/src/sgml/ref/move.sgml
index f01ee9d8a58..cd6d6aca0fd 100644
--- a/doc/src/sgml/ref/move.sgml
+++ b/doc/src/sgml/ref/move.sgml
@@ -1,5 +1,5 @@
<!--
-$Header: /cvsroot/pgsql/doc/src/sgml/ref/move.sgml,v 1.20 2003/03/11 19:40:22 tgl Exp $
+$Header: /cvsroot/pgsql/doc/src/sgml/ref/move.sgml,v 1.21 2003/03/27 16:51:27 momjian Exp $
PostgreSQL documentation
-->
@@ -64,12 +64,6 @@ MOVE [ <replaceable class="PARAMETER">direction</replaceable> { FROM | IN } ] <r
Refer to
<xref linkend="sql-declare" endterm="sql-declare-title">
to define a cursor.
- Refer to
- <xref linkend="sql-begin" endterm="sql-begin-title">,
- <xref linkend="sql-commit" endterm="sql-commit-title">,
- and
- <xref linkend="sql-rollback" endterm="sql-rollback-title">
- for further information about transactions.
</para>
</refsect2>
</refsect1>
@@ -83,7 +77,7 @@ MOVE [ <replaceable class="PARAMETER">direction</replaceable> { FROM | IN } ] <r
<programlisting>
BEGIN WORK;
-DECLARE liahona CURSOR FOR SELECT * FROM films;
+DECLARE liahona CURSOR FOR SELECT * FROM films;
-- Skip first 5 rows:
MOVE FORWARD 5 IN liahona;
<computeroutput>
diff --git a/doc/src/sgml/sql.sgml b/doc/src/sgml/sql.sgml
index 9e788ff0616..89de6668028 100644
--- a/doc/src/sgml/sql.sgml
+++ b/doc/src/sgml/sql.sgml
@@ -1,5 +1,5 @@
<!--
-$Header: /cvsroot/pgsql/doc/src/sgml/sql.sgml,v 1.29 2003/02/19 04:06:28 momjian Exp $
+$Header: /cvsroot/pgsql/doc/src/sgml/sql.sgml,v 1.30 2003/03/27 16:51:26 momjian Exp $
-->
<chapter id="sql">
@@ -851,7 +851,7 @@ A < B + 3.
<para>
The most often used command in <acronym>SQL</acronym> is the
- SELECT statement,
+ <command>SELECT</command> statement,
used to retrieve data. The syntax is:
<synopsis>
@@ -881,7 +881,7 @@ SELECT [ ALL | DISTINCT [ ON ( <replaceable class="PARAMETER">expression</replac
<title>Simple Selects</title>
<para>
- Here are some simple examples using a SELECT statement:
+ Here are some simple examples using a <command>SELECT</command> statement:
<example>
<title id="simple-query">Simple Query with Qualification</title>
@@ -905,9 +905,10 @@ SELECT * FROM PART
</para>
<para>
- Using <quote>*</quote> in the SELECT statement will deliver all attributes from
- the table. If we want to retrieve only the attributes PNAME and PRICE
- from table PART we use the statement:
+ Using <quote>*</quote> in the <command>SELECT</command> statement
+ will deliver all attributes from the table. If we want to retrieve
+ only the attributes PNAME and PRICE from table PART we use the
+ statement:
<programlisting>
SELECT PNAME, PRICE
@@ -924,9 +925,9 @@ SELECT PNAME, PRICE
Cam | 25
</programlisting>
- Note that the <acronym>SQL</acronym> SELECT corresponds to the
- <quote>projection</quote> in relational algebra not to the
- <quote>selection</quote> (see <xref linkend="rel-alg"
+ Note that the <acronym>SQL</acronym> <command>SELECT</command>
+ corresponds to the <quote>projection</quote> in relational algebra
+ not to the <quote>selection</quote> (see <xref linkend="rel-alg"
endterm="rel-alg"> for more details).
</para>
@@ -1252,15 +1253,15 @@ select sname, pname from supplier
<title id="aggregates-tutorial">Aggregate Operators</title>
<para>
- <acronym>SQL</acronym> provides aggregate operators
- (e.g. AVG, COUNT, SUM, MIN, MAX) that
- take an expression as argument. The expression is evaluated at
- each row that satisfies the WHERE clause, and the aggregate operator
- is calculated over this set of input values. Normally, an aggregate
- delivers a single result for a whole SELECT statement. But if
- grouping is specified in the query, then a separate calculation is done
- over the rows of each group, and an aggregate result is delivered per
- group (see next section).
+ <acronym>SQL</acronym> provides aggregate operators (e.g. AVG,
+ COUNT, SUM, MIN, MAX) that take an expression as argument. The
+ expression is evaluated at each row that satisfies the WHERE
+ clause, and the aggregate operator is calculated over this set
+ of input values. Normally, an aggregate delivers a single
+ result for a whole <command>SELECT</command> statement. But if
+ grouping is specified in the query, then a separate calculation
+ is done over the rows of each group, and an aggregate result is
+ delivered per group (see next section).
<example>
<title id="aggregates-example">Aggregates</title>
@@ -1413,11 +1414,12 @@ SELECT S.SNO, S.SNAME, COUNT(SE.PNO)
</para>
<para>
- Also observe that it makes no sense to ask for an aggregate of an
- aggregate, e.g., AVG(MAX(sno)), because a SELECT only does one pass
- of grouping and aggregation. You can get a result of this kind by
- using a temporary table or a sub-SELECT in the FROM clause to
- do the first level of aggregation.
+ Also observe that it makes no sense to ask for an aggregate of
+ an aggregate, e.g., AVG(MAX(sno)), because a
+ <command>SELECT</command> only does one pass of grouping and
+ aggregation. You can get a result of this kind by using a
+ temporary table or a sub-SELECT in the FROM clause to do the
+ first level of aggregation.
</para>
</sect3>
@@ -1502,16 +1504,18 @@ SELECT *
</para>
<para>
- When we look at the above query we can see
- the keyword SELECT two times. The first one at the beginning of the
- query - we will refer to it as outer SELECT - and the one in the WHERE
- clause which begins a nested query - we will refer to it as inner
- SELECT. For every tuple of the outer SELECT the inner SELECT has to be
- evaluated. After every evaluation we know the price of the tuple named
- 'Screw' and we can check if the price of the actual tuple is
- greater. (Actually, in this example the inner query need only be
- evaluated once, since it does not depend on the state of the outer
- query.)
+ When we look at the above query we can see the keyword
+ <command>SELECT</command> two times. The first one at the
+ beginning of the query - we will refer to it as outer
+ <command>SELECT</command> - and the one in the WHERE clause which
+ begins a nested query - we will refer to it as inner
+ <command>SELECT</command>. For every tuple of the outer
+ <command>SELECT</command> the inner <command>SELECT</command> has
+ to be evaluated. After every evaluation we know the price of the
+ tuple named 'Screw' and we can check if the price of the actual
+ tuple is greater. (Actually, in this example the inner query need
+ only be evaluated once, since it does not depend on the state of
+ the outer query.)
</para>
<para>
@@ -1528,11 +1532,13 @@ SELECT *
</para>
<para>
- In our example the result will be empty because every supplier sells
- at least one part. Note that we use S.SNO from the outer SELECT within
- the WHERE clause of the inner SELECT. Here the subquery must be
- evaluated afresh for each tuple from the outer query, i.e. the value for
- S.SNO is always taken from the current tuple of the outer SELECT.
+ In our example the result will be empty because every supplier
+ sells at least one part. Note that we use S.SNO from the outer
+ <command>SELECT</command> within the WHERE clause of the inner
+ <command>SELECT</command>. Here the subquery must be evaluated
+ afresh for each tuple from the outer query, i.e. the value for
+ S.SNO is always taken from the current tuple of the outer
+ <command>SELECT</command>.
</para>
</example>
</para>
@@ -1670,7 +1676,7 @@ EXCEPT
<para>
The most fundamental command for data definition is the
one that creates a new relation (a new table). The syntax of the
- CREATE TABLE command is:
+ <command>CREATE TABLE</command> command is:
<synopsis>
CREATE TABLE <replaceable class="parameter">table_name</replaceable>
@@ -1786,7 +1792,7 @@ CREATE TABLE SELLS
<para>
To create an index in <acronym>SQL</acronym>
- the CREATE INDEX command is used. The syntax is:
+ the <command>CREATE INDEX</command> command is used. The syntax is:
<programlisting>
CREATE INDEX <replaceable class="parameter">index_name</replaceable>
@@ -1808,10 +1814,11 @@ CREATE INDEX I ON SUPPLIER (SNAME);
</para>
<para>
- The created index is maintained automatically, i.e. whenever a new tuple
- is inserted into the relation SUPPLIER the index I is adapted. Note
- that the only changes a user can perceive when an index is present
- are increased speed for SELECT and decreases in speed of updates.
+ The created index is maintained automatically, i.e. whenever a new
+ tuple is inserted into the relation SUPPLIER the index I is
+ adapted. Note that the only changes a user can perceive when an
+ index is present are increased speed for <command>SELECT</command>
+ and decreases in speed of updates.
</para>
</example>
</para>
@@ -1916,7 +1923,7 @@ SELECT * FROM London_Suppliers
<para>
To destroy a table (including all tuples stored in that table) the
- DROP TABLE command is used:
+ <command>DROP TABLE</command> command is used:
<programlisting>
DROP TABLE <replaceable class="parameter">table_name</replaceable>;
@@ -1932,7 +1939,7 @@ DROP TABLE SUPPLIER;
</para>
<para>
- The DROP INDEX command is used to destroy an index:
+ The <command>DROP INDEX</command> command is used to destroy an index:
<programlisting>
DROP INDEX <replaceable class="parameter">index_name</replaceable>;
@@ -1940,7 +1947,8 @@ DROP INDEX <replaceable class="parameter">index_name</replaceable>;
</para>
<para>
- Finally to destroy a given view use the command DROP VIEW:
+ Finally to destroy a given view use the command <command>DROP
+ VIEW</command>:
<programlisting>
DROP VIEW <replaceable class="parameter">view_name</replaceable>;
@@ -1994,7 +2002,7 @@ INSERT INTO SELLS (SNO, PNO)
<para>
To change one or more attribute values of tuples in a relation the
- UPDATE command is used. The syntax is:
+ <command>UPDATE</command> command is used. The syntax is:
<programlisting>
UPDATE <replaceable class="parameter">table_name</replaceable>
@@ -2126,7 +2134,7 @@ DELETE FROM SUPPLIER
need a mechanism to access every single tuple of the set of tuples
returned by a SELECT statement. This mechanism can be provided by
declaring a <firstterm>cursor</firstterm>.
- After that we can use the FETCH command to
+ After that we can use the <command>FETCH</command> command to
retrieve a tuple and set the cursor to the next tuple.
</para>
diff --git a/src/backend/access/transam/xact.c b/src/backend/access/transam/xact.c
index 3f172dddfc6..598e3c880e5 100644
--- a/src/backend/access/transam/xact.c
+++ b/src/backend/access/transam/xact.c
@@ -8,7 +8,7 @@
*
*
* IDENTIFICATION
- * $Header: /cvsroot/pgsql/src/backend/access/transam/xact.c,v 1.144 2003/03/21 04:33:15 momjian Exp $
+ * $Header: /cvsroot/pgsql/src/backend/access/transam/xact.c,v 1.145 2003/03/27 16:51:27 momjian Exp $
*
* NOTES
* Transaction aborts can now occur two ways:
@@ -926,7 +926,7 @@ CommitTransaction(void)
* access, and in fact could still cause an error...)
*/
- AtEOXact_portals();
+ AtEOXact_portals(true);
/* handle commit for large objects [ PA, 7/17/98 ] */
/* XXX probably this does not belong here */
@@ -1057,7 +1057,7 @@ AbortTransaction(void)
* do abort processing
*/
DeferredTriggerAbortXact();
- AtEOXact_portals();
+ AtEOXact_portals(false);
lo_commit(false); /* 'false' means it's abort */
AtAbort_Notify();
AtEOXact_UpdatePasswordFile(false);
diff --git a/src/backend/commands/copy.c b/src/backend/commands/copy.c
index baaf57a70ac..978429c87f7 100644
--- a/src/backend/commands/copy.c
+++ b/src/backend/commands/copy.c
@@ -1,15 +1,14 @@
/*-------------------------------------------------------------------------
*
* copy.c
- * COPY command.
- *
+ * Implements the COPY utility command.
*
* Portions Copyright (c) 1996-2002, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
*
* IDENTIFICATION
- * $Header: /cvsroot/pgsql/src/backend/commands/copy.c,v 1.189 2003/02/03 21:15:43 tgl Exp $
+ * $Header: /cvsroot/pgsql/src/backend/commands/copy.c,v 1.190 2003/03/27 16:51:27 momjian Exp $
*
*-------------------------------------------------------------------------
*/
@@ -50,6 +49,9 @@
#define ISOCTAL(c) (((c) >= '0') && ((c) <= '7'))
#define OCTVALUE(c) ((c) - '0')
+/*
+ * Represents the type of data returned by CopyReadAttribute()
+ */
typedef enum CopyReadResult
{
NORMAL_ATTR,
@@ -1311,7 +1313,7 @@ GetTypeElement(Oid type)
* *result is set to indicate what terminated the read:
* NORMAL_ATTR: column delimiter
* END_OF_LINE: newline
- * END_OF_FILE: EOF indication
+ * END_OF_FILE: EOF indicator
* In all cases, the string read up to the terminator is returned.
*
* Note: This function does not care about SQL NULL values -- it
diff --git a/src/backend/commands/portalcmds.c b/src/backend/commands/portalcmds.c
index 1ba72437ad7..7eabc58d495 100644
--- a/src/backend/commands/portalcmds.c
+++ b/src/backend/commands/portalcmds.c
@@ -8,7 +8,7 @@
*
*
* IDENTIFICATION
- * $Header: /cvsroot/pgsql/src/backend/commands/portalcmds.c,v 1.10 2003/03/11 19:40:22 tgl Exp $
+ * $Header: /cvsroot/pgsql/src/backend/commands/portalcmds.c,v 1.11 2003/03/27 16:51:27 momjian Exp $
*
*-------------------------------------------------------------------------
*/
@@ -17,18 +17,23 @@
#include <limits.h>
+#include "miscadmin.h"
#include "commands/portalcmds.h"
#include "executor/executor.h"
#include "optimizer/planner.h"
#include "rewrite/rewriteHandler.h"
-
+#include "utils/memutils.h"
static long DoRelativeFetch(Portal portal,
bool forward,
long count,
CommandDest dest);
+static long DoRelativeStoreFetch(Portal portal,
+ bool forward,
+ long count,
+ CommandDest dest);
static void DoPortalRewind(Portal portal);
-static Portal PreparePortal(char *portalName);
+static Portal PreparePortal(DeclareCursorStmt *stmt);
/*
@@ -46,8 +51,15 @@ PerformCursorOpen(DeclareCursorStmt *stmt, CommandDest dest)
char *cursorName;
QueryDesc *queryDesc;
- /* Check for invalid context (must be in transaction block) */
- RequireTransactionChain((void *) stmt, "DECLARE CURSOR");
+ /*
+ * If this is a non-holdable cursor, we ensure that this statement
+ * has been executed inside a transaction block (or else, it would
+ * have no user-visible effect).
+ *
+ * XXX: surely there is a better way to check this?
+ */
+ if (!(stmt->options & CURSOR_OPT_HOLD))
+ RequireTransactionChain((void *) stmt, "DECLARE CURSOR");
/*
* The query has been through parse analysis, but not rewriting or
@@ -76,7 +88,7 @@ PerformCursorOpen(DeclareCursorStmt *stmt, CommandDest dest)
/*
* Create a portal and copy the query and plan into its memory context.
*/
- portal = PreparePortal(stmt->portalname);
+ portal = PreparePortal(stmt);
oldContext = MemoryContextSwitchTo(PortalGetHeapMemory(portal));
query = copyObject(query);
@@ -130,6 +142,7 @@ PerformPortalFetch(FetchStmt *stmt,
portal = GetPortalByName(stmt->portalname);
if (!PortalIsValid(portal))
{
+ /* FIXME: shouldn't this be an ERROR? */
elog(WARNING, "PerformPortalFetch: portal \"%s\" not found",
stmt->portalname);
return;
@@ -343,6 +356,9 @@ DoRelativeFetch(Portal portal,
ScanDirection direction;
QueryDesc temp_queryDesc;
+ if (portal->holdStore)
+ return DoRelativeStoreFetch(portal, forward, count, dest);
+
queryDesc = PortalGetQueryDesc(portal);
estate = queryDesc->estate;
@@ -407,7 +423,7 @@ DoRelativeFetch(Portal portal,
}
else
{
- if (!portal->backwardOK)
+ if (portal->scrollType == DISABLE_SCROLL)
elog(ERROR, "Cursor can only scan forward"
"\n\tDeclare it with SCROLL option to enable backward scan");
@@ -452,17 +468,85 @@ DoRelativeFetch(Portal portal,
return estate->es_processed;
}
+/*
+ * DoRelativeStoreFetch
+ * Do fetch for a simple N-rows-forward-or-backward case, getting
+ * the results from the portal's tuple store.
+ */
+static long
+DoRelativeStoreFetch(Portal portal,
+ bool forward,
+ long count,
+ CommandDest dest)
+{
+ DestReceiver *destfunc;
+ QueryDesc *queryDesc = portal->queryDesc;
+ long rows_fetched = 0;
+
+ if (!forward && portal->scrollType == DISABLE_SCROLL)
+ elog(ERROR, "Cursor can only scan forward"
+ "\n\tDeclare it with SCROLL option to enable backward scan");
+
+ destfunc = DestToFunction(dest);
+ (*destfunc->setup) (destfunc, queryDesc->operation,
+ portal->name, queryDesc->tupDesc);
+
+ for (;;)
+ {
+ HeapTuple tup;
+ bool should_free;
+
+ if (rows_fetched >= count)
+ break;
+ if (portal->atEnd && forward)
+ break;
+ if (portal->atStart && !forward)
+ break;
+
+ tup = tuplestore_getheaptuple(portal->holdStore, forward, &should_free);
+
+ if (tup == NULL)
+ {
+ if (forward)
+ portal->atEnd = true;
+ else
+ portal->atStart = true;
+
+ break;
+ }
+
+ (*destfunc->receiveTuple) (tup, queryDesc->tupDesc, destfunc);
+
+ rows_fetched++;
+ if (forward)
+ portal->portalPos++;
+ else
+ portal->portalPos--;
+
+ if (forward && portal->atStart)
+ portal->atStart = false;
+ if (!forward && portal->atEnd)
+ portal->atEnd = false;
+
+ if (should_free)
+ pfree(tup);
+ }
+
+ (*destfunc->cleanup) (destfunc);
+
+ return rows_fetched;
+}
+
/*
* DoPortalRewind - rewind a Portal to starting point
*/
static void
DoPortalRewind(Portal portal)
{
- QueryDesc *queryDesc;
-
- queryDesc = PortalGetQueryDesc(portal);
-
- ExecutorRewind(queryDesc);
+ if (portal->holdStore)
+ tuplestore_rescan(portal->holdStore);
+ else
+ ExecutorRewind(PortalGetQueryDesc(portal));
portal->atStart = true;
portal->atEnd = false;
@@ -493,22 +577,25 @@ PerformPortalClose(char *name)
/*
* Note: PortalCleanup is called as a side-effect
*/
- PortalDrop(portal);
+ PortalDrop(portal, false);
}
-
/*
* PreparePortal
+ * Given a DECLARE CURSOR statement, returns the Portal data
+ * structure based on that statement that is used to manage the
+ * Portal internally. If a portal with specified name already
+ * exists, it is replaced.
*/
static Portal
-PreparePortal(char *portalName)
+PreparePortal(DeclareCursorStmt *stmt)
{
Portal portal;
/*
* Check for already-in-use portal name.
*/
- portal = GetPortalByName(portalName);
+ portal = GetPortalByName(stmt->portalname);
if (PortalIsValid(portal))
{
/*
@@ -516,19 +603,30 @@ PreparePortal(char *portalName)
* portal?
*/
elog(WARNING, "Closing pre-existing portal \"%s\"",
- portalName);
- PortalDrop(portal);
+ stmt->portalname);
+ PortalDrop(portal, false);
}
/*
* Create the new portal.
*/
- portal = CreatePortal(portalName);
+ portal = CreatePortal(stmt->portalname);
+
+ /*
+ * Modify the newly created portal based on the options specified in
+ * the DECLARE CURSOR statement.
+ */
+ if (stmt->options & CURSOR_OPT_SCROLL)
+ portal->scrollType = ENABLE_SCROLL;
+ else if (stmt->options & CURSOR_OPT_NO_SCROLL)
+ portal->scrollType = DISABLE_SCROLL;
+
+ if (stmt->options & CURSOR_OPT_HOLD)
+ portal->holdOpen = true;
return portal;
}
-
/*
* PortalCleanup
*
@@ -545,14 +643,128 @@ PortalCleanup(Portal portal)
AssertArg(PortalIsValid(portal));
AssertArg(portal->cleanup == PortalCleanup);
+ if (portal->holdStore)
+ tuplestore_end(portal->holdStore);
+ else
+ ExecutorEnd(PortalGetQueryDesc(portal));
+
+}
+
+/*
+ * PersistHoldablePortal
+ *
+ * Prepare the specified Portal for access outside of the current
+ * transaction. When this function returns, all future accesses to the
+ * portal must be done via the Tuplestore (not by invoking the
+ * executor).
+ */
+void
+PersistHoldablePortal(Portal portal)
+{
+ MemoryContext oldcxt;
+ QueryDesc *queryDesc = PortalGetQueryDesc(portal);
+
+ /*
+ * If we're preserving a holdable portal, we had better be
+ * inside the transaction that originally created it.
+ */
+ Assert(portal->createXact == GetCurrentTransactionId());
+ Assert(portal->holdStore == NULL);
+
+ /*
+ * This context is used to store portal data that needs to persist
+ * between transactions.
+ */
+ oldcxt = MemoryContextSwitchTo(portal->holdContext);
+
+ /* XXX: Should SortMem be used for this? */
+ portal->holdStore = tuplestore_begin_heap(true, true, SortMem);
+
+ /* Set the destination to output to the tuplestore */
+ queryDesc->dest = Tuplestore;
+
+ /*
+ * Rewind the executor: we need to store the entire result set in
+ * the tuplestore, so that subsequent backward FETCHs can be
+ * processed.
+ */
+ ExecutorRewind(queryDesc);
+
+ /* Fetch the result set into the tuplestore */
+ ExecutorRun(queryDesc, ForwardScanDirection, 0);
+
+ /*
+ * Reset the position in the result set: ideally, this could be
+ * implemented by just skipping straight to the tuple # that we need
+ * to be at, but the tuplestore API doesn't support that. So we
+ * start at the beginning of the tuplestore and iterate through it
+ * until we reach where we need to be.
+ */
+ if (!portal->atEnd)
+ {
+ int store_pos = 0;
+ bool should_free;
+
+ tuplestore_rescan(portal->holdStore);
+
+ while (store_pos < portal->portalPos)
+ {
+ HeapTuple tmp = tuplestore_gettuple(portal->holdStore,
+ true, &should_free);
+
+ if (tmp == NULL)
+ elog(ERROR,
+ "PersistHoldablePortal: unexpected end of tuple stream");
+
+ store_pos++;
+
+ /*
+ * This could probably be optimized by creating and then
+ * deleting a separate memory context for this series of
+ * operations.
+ */
+ if (should_free)
+ pfree(tmp);
+ }
+ }
+
/*
- * tell the executor to shutdown the query
+ * The current Portal structure contains some data that will be
+ * needed by the holdable cursor, but it has been allocated in a
+ * memory context that is not sufficiently long-lived: we need to
+ * copy it into the portal's long-term memory context.
*/
- ExecutorEnd(PortalGetQueryDesc(portal));
+ {
+ TupleDesc tupDescCopy;
+ QueryDesc *queryDescCopy;
+
+ /*
+ * We need to use this order as ExecutorEnd invalidates the
+ * queryDesc's tuple descriptor
+ */
+ tupDescCopy = CreateTupleDescCopy(queryDesc->tupDesc);
+
+ ExecutorEnd(queryDesc);
+
+ queryDescCopy = palloc(sizeof(*queryDescCopy));
+
+ /*
+ * This doesn't copy all the dependant data in the QueryDesc,
+ * but that's okay -- the only complex field we need to keep is
+ * the query's tupledesc, which we've copied ourselves.
+ */
+ memcpy(queryDescCopy, queryDesc, sizeof(*queryDesc));
+
+ FreeQueryDesc(queryDesc);
+
+ queryDescCopy->tupDesc = tupDescCopy;
+ portal->queryDesc = queryDescCopy;
+ }
/*
- * This should be unnecessary since the querydesc should be in the
- * portal's memory context, but do it anyway for symmetry.
+ * We no longer need the portal's short-term memory context.
*/
- FreeQueryDesc(PortalGetQueryDesc(portal));
+ MemoryContextDelete(PortalGetHeapMemory(portal));
+
+ PortalGetHeapMemory(portal) = NULL;
}
diff --git a/src/backend/executor/Makefile b/src/backend/executor/Makefile
index 7e3f5d2d2c8..cc49bd6d69e 100644
--- a/src/backend/executor/Makefile
+++ b/src/backend/executor/Makefile
@@ -4,7 +4,7 @@
# Makefile for executor
#
# IDENTIFICATION
-# $Header: /cvsroot/pgsql/src/backend/executor/Makefile,v 1.20 2003/01/10 23:54:24 tgl Exp $
+# $Header: /cvsroot/pgsql/src/backend/executor/Makefile,v 1.21 2003/03/27 16:51:27 momjian Exp $
#
#-------------------------------------------------------------------------
@@ -18,7 +18,7 @@ OBJS = execAmi.o execGrouping.o execJunk.o execMain.o \
nodeHashjoin.o nodeIndexscan.o nodeMaterial.o nodeMergejoin.o \
nodeNestloop.o nodeFunctionscan.o nodeResult.o nodeSeqscan.o \
nodeSetOp.o nodeSort.o nodeUnique.o nodeLimit.o nodeGroup.o \
- nodeSubplan.o nodeSubqueryscan.o nodeTidscan.o spi.o
+ nodeSubplan.o nodeSubqueryscan.o nodeTidscan.o tstoreReceiver.o spi.o
all: SUBSYS.o
diff --git a/src/backend/executor/execMain.c b/src/backend/executor/execMain.c
index 1266895a5f6..485f1e03fa0 100644
--- a/src/backend/executor/execMain.c
+++ b/src/backend/executor/execMain.c
@@ -26,7 +26,7 @@
*
*
* IDENTIFICATION
- * $Header: /cvsroot/pgsql/src/backend/executor/execMain.c,v 1.204 2003/03/27 14:33:11 tgl Exp $
+ * $Header: /cvsroot/pgsql/src/backend/executor/execMain.c,v 1.205 2003/03/27 16:51:27 momjian Exp $
*
*-------------------------------------------------------------------------
*/
@@ -217,8 +217,8 @@ ExecutorRun(QueryDesc *queryDesc,
estate->es_lastoid = InvalidOid;
destfunc = DestToFunction(dest);
- (*destfunc->setup) (destfunc, (int) operation,
- queryDesc->portalName, queryDesc->tupDesc);
+ (*destfunc->setup) (destfunc, operation, queryDesc->portalName,
+ queryDesc->tupDesc);
/*
* run plan
@@ -421,15 +421,6 @@ ExecCheckRTEPerms(RangeTblEntry *rte, CmdType operation)
}
}
-
-/* ===============================================================
- * ===============================================================
- static routines follow
- * ===============================================================
- * ===============================================================
- */
-
-
static void
ExecCheckXactReadOnly(Query *parsetree, CmdType operation)
{
diff --git a/src/backend/executor/execQual.c b/src/backend/executor/execQual.c
index a1c1fdd8ad3..7e084f28302 100644
--- a/src/backend/executor/execQual.c
+++ b/src/backend/executor/execQual.c
@@ -8,7 +8,7 @@
*
*
* IDENTIFICATION
- * $Header: /cvsroot/pgsql/src/backend/executor/execQual.c,v 1.126 2003/03/09 02:19:13 tgl Exp $
+ * $Header: /cvsroot/pgsql/src/backend/executor/execQual.c,v 1.127 2003/03/27 16:51:27 momjian Exp $
*
*-------------------------------------------------------------------------
*/
@@ -1054,8 +1054,7 @@ ExecMakeTableFunctionResult(ExprState *funcexpr,
0,
false);
}
- tupstore = tuplestore_begin_heap(true, /* randomAccess */
- SortMem);
+ tupstore = tuplestore_begin_heap(true, false, SortMem);
MemoryContextSwitchTo(oldcontext);
rsinfo.setResult = tupstore;
rsinfo.setDesc = tupdesc;
diff --git a/src/backend/executor/nodeHash.c b/src/backend/executor/nodeHash.c
index 31152a3d855..b338c8961e2 100644
--- a/src/backend/executor/nodeHash.c
+++ b/src/backend/executor/nodeHash.c
@@ -8,7 +8,7 @@
*
*
* IDENTIFICATION
- * $Header: /cvsroot/pgsql/src/backend/executor/nodeHash.c,v 1.74 2003/01/10 23:54:24 tgl Exp $
+ * $Header: /cvsroot/pgsql/src/backend/executor/nodeHash.c,v 1.75 2003/03/27 16:51:27 momjian Exp $
*
*-------------------------------------------------------------------------
*/
@@ -64,7 +64,7 @@ ExecHash(HashState *node)
* buffers are palloc'd in regular executor context.
*/
for (i = 0; i < nbatch; i++)
- hashtable->innerBatchFile[i] = BufFileCreateTemp();
+ hashtable->innerBatchFile[i] = BufFileCreateTemp(false);
}
/*
diff --git a/src/backend/executor/nodeHashjoin.c b/src/backend/executor/nodeHashjoin.c
index 3603fd9b680..4bc1671801f 100644
--- a/src/backend/executor/nodeHashjoin.c
+++ b/src/backend/executor/nodeHashjoin.c
@@ -8,7 +8,7 @@
*
*
* IDENTIFICATION
- * $Header: /cvsroot/pgsql/src/backend/executor/nodeHashjoin.c,v 1.48 2003/01/27 20:51:48 tgl Exp $
+ * $Header: /cvsroot/pgsql/src/backend/executor/nodeHashjoin.c,v 1.49 2003/03/27 16:51:27 momjian Exp $
*
*-------------------------------------------------------------------------
*/
@@ -138,7 +138,7 @@ ExecHashJoin(HashJoinState *node)
* buffers are palloc'd in regular executor context.
*/
for (i = 0; i < hashtable->nbatch; i++)
- hashtable->outerBatchFile[i] = BufFileCreateTemp();
+ hashtable->outerBatchFile[i] = BufFileCreateTemp(false);
}
else if (hashtable == NULL)
return NULL;
diff --git a/src/backend/executor/nodeMaterial.c b/src/backend/executor/nodeMaterial.c
index 2566851dccc..39968c65e0c 100644
--- a/src/backend/executor/nodeMaterial.c
+++ b/src/backend/executor/nodeMaterial.c
@@ -8,7 +8,7 @@
*
*
* IDENTIFICATION
- * $Header: /cvsroot/pgsql/src/backend/executor/nodeMaterial.c,v 1.41 2003/03/09 02:19:13 tgl Exp $
+ * $Header: /cvsroot/pgsql/src/backend/executor/nodeMaterial.c,v 1.42 2003/03/27 16:51:27 momjian Exp $
*
*-------------------------------------------------------------------------
*/
@@ -62,8 +62,7 @@ ExecMaterial(MaterialState *node)
*/
if (tuplestorestate == NULL)
{
- tuplestorestate = tuplestore_begin_heap(true, /* randomAccess */
- SortMem);
+ tuplestorestate = tuplestore_begin_heap(true, false, SortMem);
node->tuplestorestate = (void *) tuplestorestate;
}
diff --git a/src/backend/executor/spi.c b/src/backend/executor/spi.c
index 61eed9b4004..7184fbf9ba1 100644
--- a/src/backend/executor/spi.c
+++ b/src/backend/executor/spi.c
@@ -8,7 +8,7 @@
*
*
* IDENTIFICATION
- * $Header: /cvsroot/pgsql/src/backend/executor/spi.c,v 1.88 2003/03/11 19:40:22 tgl Exp $
+ * $Header: /cvsroot/pgsql/src/backend/executor/spi.c,v 1.89 2003/03/27 16:51:28 momjian Exp $
*
*-------------------------------------------------------------------------
*/
@@ -866,7 +866,7 @@ SPI_cursor_close(Portal portal)
if (!PortalIsValid(portal))
elog(ERROR, "invalid portal in SPI cursor operation");
- PortalDrop(portal);
+ PortalDrop(portal, false);
}
/* =================== private functions =================== */
diff --git a/src/backend/parser/analyze.c b/src/backend/parser/analyze.c
index 3486a1e010b..64cd5603acd 100644
--- a/src/backend/parser/analyze.c
+++ b/src/backend/parser/analyze.c
@@ -6,7 +6,7 @@
* Portions Copyright (c) 1996-2002, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
- * $Header: /cvsroot/pgsql/src/backend/parser/analyze.c,v 1.265 2003/03/10 03:53:50 tgl Exp $
+ * $Header: /cvsroot/pgsql/src/backend/parser/analyze.c,v 1.266 2003/03/27 16:51:28 momjian Exp $
*
*-------------------------------------------------------------------------
*/
@@ -2294,6 +2294,13 @@ transformDeclareCursorStmt(ParseState *pstate, DeclareCursorStmt *stmt)
result->commandType = CMD_UTILITY;
result->utilityStmt = (Node *) stmt;
+ /*
+ * Don't allow both SCROLL and NO SCROLL to be specified
+ */
+ if ((stmt->options & CURSOR_OPT_SCROLL) &&
+ (stmt->options & CURSOR_OPT_NO_SCROLL))
+ elog(ERROR, "Both SCROLL and NO SCROLL cannot be specified.");
+
stmt->query = (Node *) transformStmt(pstate, stmt->query,
&extras_before, &extras_after);
diff --git a/src/backend/parser/gram.y b/src/backend/parser/gram.y
index dc8b06e7507..0ee065a9a11 100644
--- a/src/backend/parser/gram.y
+++ b/src/backend/parser/gram.y
@@ -11,7 +11,7 @@
*
*
* IDENTIFICATION
- * $Header: /cvsroot/pgsql/src/backend/parser/gram.y,v 2.408 2003/03/20 18:52:47 momjian Exp $
+ * $Header: /cvsroot/pgsql/src/backend/parser/gram.y,v 2.409 2003/03/27 16:51:28 momjian Exp $
*
* HISTORY
* AUTHOR DATE MAJOR EVENT
@@ -246,7 +246,7 @@ static void doNegateFloat(Value *v);
%type <boolean> opt_freeze opt_default opt_recheck
%type <defelt> opt_binary opt_oids copy_delimiter
-%type <boolean> copy_from
+%type <boolean> copy_from opt_hold
%type <ival> reindex_type drop_type fetch_count
opt_column event comment_type cursor_options
@@ -348,7 +348,7 @@ static void doNegateFloat(Value *v);
GLOBAL GRANT GROUP_P
- HANDLER HAVING HOUR_P
+ HANDLER HAVING HOLD HOUR_P
ILIKE IMMEDIATE IMMUTABLE IMPLICIT_P IN_P INCREMENT
INDEX INHERITS INITIALLY INNER_P INOUT INPUT
@@ -4230,22 +4230,31 @@ UpdateStmt: UPDATE relation_expr
* CURSOR STATEMENTS
*
*****************************************************************************/
-DeclareCursorStmt: DECLARE name cursor_options CURSOR FOR SelectStmt
+DeclareCursorStmt: DECLARE name cursor_options CURSOR opt_hold FOR SelectStmt
{
DeclareCursorStmt *n = makeNode(DeclareCursorStmt);
n->portalname = $2;
n->options = $3;
- n->query = $6;
+ n->query = $7;
+
+ if ($5)
+ n->options |= CURSOR_OPT_HOLD;
+
$$ = (Node *)n;
}
;
cursor_options: /*EMPTY*/ { $$ = 0; }
- | cursor_options BINARY { $$ = $1 | CURSOR_OPT_BINARY; }
+ | cursor_options NO SCROLL { $$ = $1 | CURSOR_OPT_NO_SCROLL; }
| cursor_options SCROLL { $$ = $1 | CURSOR_OPT_SCROLL; }
+ | cursor_options BINARY { $$ = $1 | CURSOR_OPT_BINARY; }
| cursor_options INSENSITIVE { $$ = $1 | CURSOR_OPT_INSENSITIVE; }
;
+opt_hold: /* EMPTY */ { $$ = FALSE; }
+ | WITH HOLD { $$ = TRUE; }
+ | WITHOUT HOLD { $$ = FALSE; }
+
/*****************************************************************************
*
* QUERY:
diff --git a/src/backend/parser/keywords.c b/src/backend/parser/keywords.c
index 83608d95edb..d62f5668d5d 100644
--- a/src/backend/parser/keywords.c
+++ b/src/backend/parser/keywords.c
@@ -8,7 +8,7 @@
*
*
* IDENTIFICATION
- * $Header: /cvsroot/pgsql/src/backend/parser/keywords.c,v 1.136 2003/03/20 07:02:10 momjian Exp $
+ * $Header: /cvsroot/pgsql/src/backend/parser/keywords.c,v 1.137 2003/03/27 16:51:28 momjian Exp $
*
*-------------------------------------------------------------------------
*/
@@ -143,6 +143,7 @@ static const ScanKeyword ScanKeywords[] = {
{"group", GROUP_P},
{"handler", HANDLER},
{"having", HAVING},
+ {"hold", HOLD},
{"hour", HOUR_P},
{"ilike", ILIKE},
{"immediate", IMMEDIATE},
diff --git a/src/backend/storage/file/buffile.c b/src/backend/storage/file/buffile.c
index 7e78793a404..90b185cd5de 100644
--- a/src/backend/storage/file/buffile.c
+++ b/src/backend/storage/file/buffile.c
@@ -7,7 +7,7 @@
* Portions Copyright (c) 1994, Regents of the University of California
*
* IDENTIFICATION
- * $Header: /cvsroot/pgsql/src/backend/storage/file/buffile.c,v 1.14 2002/09/05 00:43:07 tgl Exp $
+ * $Header: /cvsroot/pgsql/src/backend/storage/file/buffile.c,v 1.15 2003/03/27 16:51:29 momjian Exp $
*
* NOTES:
*
@@ -64,6 +64,7 @@ struct BufFile
*/
bool isTemp; /* can only add files if this is TRUE */
+ bool isInterTxn; /* keep open over transactions? */
bool dirty; /* does buffer need to be written? */
/*
@@ -118,7 +119,7 @@ extendBufFile(BufFile *file)
File pfile;
Assert(file->isTemp);
- pfile = OpenTemporaryFile();
+ pfile = OpenTemporaryFile(file->isInterTxn);
Assert(pfile >= 0);
file->files = (File *) repalloc(file->files,
@@ -136,16 +137,17 @@ extendBufFile(BufFile *file)
* written to it).
*/
BufFile *
-BufFileCreateTemp(void)
+BufFileCreateTemp(bool interTxn)
{
BufFile *file;
File pfile;
- pfile = OpenTemporaryFile();
+ pfile = OpenTemporaryFile(interTxn);
Assert(pfile >= 0);
file = makeBufFile(pfile);
file->isTemp = true;
+ file->isInterTxn = interTxn;
return file;
}
diff --git a/src/backend/storage/file/fd.c b/src/backend/storage/file/fd.c
index 83c97fb7550..7607d4186cc 100644
--- a/src/backend/storage/file/fd.c
+++ b/src/backend/storage/file/fd.c
@@ -7,7 +7,7 @@
* Portions Copyright (c) 1994, Regents of the University of California
*
* IDENTIFICATION
- * $Header: /cvsroot/pgsql/src/backend/storage/file/fd.c,v 1.95 2002/09/02 06:11:42 momjian Exp $
+ * $Header: /cvsroot/pgsql/src/backend/storage/file/fd.c,v 1.96 2003/03/27 16:51:29 momjian Exp $
*
* NOTES:
*
@@ -112,14 +112,14 @@ int max_files_per_process = 1000;
#define FileUnknownPos (-1L)
+/* these are the assigned bits in fdstate below: */
+#define FD_TEMPORARY (1 << 0)
+#define FD_TXN_TEMPORARY (1 << 1)
+
typedef struct vfd
{
signed short fd; /* current FD, or VFD_CLOSED if none */
unsigned short fdstate; /* bitflags for VFD's state */
-
-/* these are the assigned bits in fdstate: */
-#define FD_TEMPORARY (1 << 0) /* should be unlinked when closed */
-
File nextFree; /* link to next free VFD, if in freelist */
File lruMoreRecently; /* doubly linked recency-of-use list */
File lruLessRecently;
@@ -750,9 +750,15 @@ PathNameOpenFile(FileName fileName, int fileFlags, int fileMode)
* This routine takes care of generating an appropriate tempfile name.
* There's no need to pass in fileFlags or fileMode either, since only
* one setting makes any sense for a temp file.
+ *
+ * keepOverTxn: if true, don't close the file at end-of-transaction. In
+ * most cases, you don't want temporary files to outlive the transaction
+ * that created them, so this should be false -- but if you need
+ * "somewhat" temporary storage, this might be useful. In either case,
+ * the file is removed when the File is explicitely closed.
*/
File
-OpenTemporaryFile(void)
+OpenTemporaryFile(bool keepOverTxn)
{
char tempfilepath[128];
File file;
@@ -795,9 +801,13 @@ OpenTemporaryFile(void)
elog(ERROR, "Failed to create temporary file %s", tempfilepath);
}
- /* Mark it for deletion at close or EOXact */
+ /* Mark it for deletion at close */
VfdCache[file].fdstate |= FD_TEMPORARY;
+ /* Mark it for deletion at EOXact */
+ if (!keepOverTxn)
+ VfdCache[file].fdstate |= FD_TXN_TEMPORARY;
+
return file;
}
@@ -1114,6 +1124,7 @@ AtEOXact_Files(void)
for (i = 1; i < SizeVfdCache; i++)
{
if ((VfdCache[i].fdstate & FD_TEMPORARY) &&
+ (VfdCache[i].fdstate & FD_TXN_TEMPORARY) &&
VfdCache[i].fileName != NULL)
FileClose(i);
}
diff --git a/src/backend/tcop/dest.c b/src/backend/tcop/dest.c
index 516af21a466..ad9d2327717 100644
--- a/src/backend/tcop/dest.c
+++ b/src/backend/tcop/dest.c
@@ -8,7 +8,7 @@
* Portions Copyright (c) 1994, Regents of the University of California
*
* IDENTIFICATION
- * $Header: /cvsroot/pgsql/src/backend/tcop/dest.c,v 1.50 2003/01/21 22:06:12 tgl Exp $
+ * $Header: /cvsroot/pgsql/src/backend/tcop/dest.c,v 1.51 2003/03/27 16:51:29 momjian Exp $
*
*-------------------------------------------------------------------------
*/
@@ -29,6 +29,7 @@
#include "postgres.h"
#include "access/printtup.h"
+#include "executor/tstoreReceiver.h"
#include "libpq/libpq.h"
#include "libpq/pqformat.h"
@@ -60,9 +61,11 @@ donothingCleanup(DestReceiver *self)
static DestReceiver donothingDR = {
donothingReceive, donothingSetup, donothingCleanup
};
+
static DestReceiver debugtupDR = {
debugtup, debugSetup, donothingCleanup
};
+
static DestReceiver spi_printtupDR = {
spi_printtup, spi_dest_setup, donothingCleanup
};
@@ -98,6 +101,9 @@ DestToFunction(CommandDest dest)
case SPI:
return &spi_printtupDR;
+ case Tuplestore:
+ return tstoreReceiverCreateDR();
+
case None:
return &donothingDR;
}
@@ -122,6 +128,7 @@ EndCommand(const char *commandTag, CommandDest dest)
case None:
case Debug:
+ case Tuplestore:
case SPI:
break;
}
@@ -183,6 +190,7 @@ NullCommand(CommandDest dest)
break;
case Debug:
+ case Tuplestore:
case None:
default:
break;
@@ -213,6 +221,7 @@ ReadyForQuery(CommandDest dest)
break;
case Debug:
+ case Tuplestore:
case None:
default:
break;
diff --git a/src/backend/utils/mmgr/mcxt.c b/src/backend/utils/mmgr/mcxt.c
index 48545b15128..729137a1b92 100644
--- a/src/backend/utils/mmgr/mcxt.c
+++ b/src/backend/utils/mmgr/mcxt.c
@@ -14,7 +14,7 @@
*
*
* IDENTIFICATION
- * $Header: /cvsroot/pgsql/src/backend/utils/mmgr/mcxt.c,v 1.38 2002/12/16 16:22:46 tgl Exp $
+ * $Header: /cvsroot/pgsql/src/backend/utils/mmgr/mcxt.c,v 1.39 2003/03/27 16:51:29 momjian Exp $
*
*-------------------------------------------------------------------------
*/
@@ -36,7 +36,8 @@
MemoryContext CurrentMemoryContext = NULL;
/*
- * Standard top-level contexts
+ * Standard top-level contexts. For a description of the purpose of each
+ * of these contexts, refer to src/backend/utils/mmgr/README
*/
MemoryContext TopMemoryContext = NULL;
MemoryContext ErrorContext = NULL;
diff --git a/src/backend/utils/mmgr/portalmem.c b/src/backend/utils/mmgr/portalmem.c
index 66ee72718cf..e6486d4b16d 100644
--- a/src/backend/utils/mmgr/portalmem.c
+++ b/src/backend/utils/mmgr/portalmem.c
@@ -8,7 +8,7 @@
*
*
* IDENTIFICATION
- * $Header: /cvsroot/pgsql/src/backend/utils/mmgr/portalmem.c,v 1.53 2003/03/11 19:40:23 tgl Exp $
+ * $Header: /cvsroot/pgsql/src/backend/utils/mmgr/portalmem.c,v 1.54 2003/03/27 16:51:29 momjian Exp $
*
*-------------------------------------------------------------------------
*/
@@ -20,8 +20,8 @@
* "PortalData" structure, plans the query and then stores the query
* in the portal without executing it. Later, when the backend
* sees a
- * fetch 1 from FOO
- * the system looks up the portal named "FOO" in the portal table,
+ * fetch 1 from foo
+ * the system looks up the portal named "foo" in the portal table,
* gets the planned query and then calls the executor with a count
* of 1. The executor then runs the query and returns a single
* tuple. The problem is that we have to hold onto the state of the
@@ -38,7 +38,6 @@
#include "utils/memutils.h"
#include "utils/portal.h"
-
/*
* estimate of the maximum number of open portals a user would have,
* used in initially sizing the PortalHashTable in EnablePortalManager()
@@ -131,8 +130,8 @@ EnablePortalManager(void)
ctl.entrysize = sizeof(PortalHashEnt);
/*
- * use PORTALS_PER_USER, defined in utils/portal.h as a guess of how
- * many hash table entries to create, initially
+ * use PORTALS_PER_USER as a guess of how many hash table entries to
+ * create, initially
*/
PortalHashTable = hash_create("Portal hash", PORTALS_PER_USER,
&ctl, HASH_ELEM);
@@ -157,7 +156,9 @@ GetPortalByName(const char *name)
/*
* PortalSetQuery
- * Attaches a "query" to portal.
+ * Attaches a "query" to the specified portal. Note that in the
+ * case of DECLARE CURSOR, some Portal options have already been
+ * set based upon the parsetree of the original DECLARE statement.
*/
void
PortalSetQuery(Portal portal,
@@ -166,9 +167,25 @@ PortalSetQuery(Portal portal,
{
AssertArg(PortalIsValid(portal));
+ /*
+ * If the user didn't specify a SCROLL type, allow or disallow
+ * scrolling based on whether it would require any additional
+ * runtime overhead to do so.
+ */
+ if (portal->scrollType == DEFAULT_SCROLL)
+ {
+ bool backwardPlan;
+
+ backwardPlan = ExecSupportsBackwardScan(queryDesc->plantree);
+
+ if (backwardPlan)
+ portal->scrollType = ENABLE_SCROLL;
+ else
+ portal->scrollType = DISABLE_SCROLL;
+ }
+
portal->queryDesc = queryDesc;
portal->cleanup = cleanup;
- portal->backwardOK = ExecSupportsBackwardScan(queryDesc->plantree);
portal->atStart = true;
portal->atEnd = false; /* allow fetches */
portal->portalPos = 0;
@@ -179,10 +196,8 @@ PortalSetQuery(Portal portal,
* CreatePortal
* Returns a new portal given a name.
*
- * Exceptions:
- * BadState if called when disabled.
- * BadArg if portal name is invalid.
- * "WARNING" if portal name is in use (existing portal is returned!)
+ * An elog(WARNING) is emitted if portal name is in use (existing
+ * portal is returned!)
*/
Portal
CreatePortal(const char *name)
@@ -214,7 +229,11 @@ CreatePortal(const char *name)
/* initialize portal query */
portal->queryDesc = NULL;
portal->cleanup = NULL;
- portal->backwardOK = false;
+ portal->scrollType = DEFAULT_SCROLL;
+ portal->holdOpen = false;
+ portal->holdStore = NULL;
+ portal->holdContext = NULL;
+ portal->createXact = GetCurrentTransactionId();
portal->atStart = true;
portal->atEnd = true; /* disallow fetches until query is set */
portal->portalPos = 0;
@@ -228,17 +247,47 @@ CreatePortal(const char *name)
/*
* PortalDrop
- * Destroys portal.
+ * Destroy the portal.
*
- * Exceptions:
- * BadState if called when disabled.
- * BadArg if portal is invalid.
+ * keepHoldable: if true, holdable portals should not be removed by
+ * this function. More specifically, invoking this function with
+ * keepHoldable = true on a holdable portal prepares the portal for
+ * access outside of its creating transaction.
*/
void
-PortalDrop(Portal portal)
+PortalDrop(Portal portal, bool persistHoldable)
{
AssertArg(PortalIsValid(portal));
+ if (portal->holdOpen && persistHoldable)
+ {
+ /*
+ * We're "dropping" a holdable portal, but what we really need
+ * to do is prepare the portal for access outside of its
+ * creating transaction.
+ */
+
+ /*
+ * Create the memory context that is used for storage of
+ * long-term (cross transaction) data needed by the holdable
+ * portal.
+ */
+ portal->holdContext =
+ AllocSetContextCreate(PortalMemory,
+ "PortalHeapMemory",
+ ALLOCSET_DEFAULT_MINSIZE,
+ ALLOCSET_DEFAULT_INITSIZE,
+ ALLOCSET_DEFAULT_MAXSIZE);
+
+ /*
+ * Note that PersistHoldablePortal() releases any resources used
+ * by the portal that are local to the creating txn.
+ */
+ PersistHoldablePortal(portal);
+
+ return;
+ }
+
/* remove portal from hash table */
PortalHashTableDelete(portal);
@@ -246,8 +295,20 @@ PortalDrop(Portal portal)
if (PointerIsValid(portal->cleanup))
(*portal->cleanup) (portal);
- /* release subsidiary storage */
- MemoryContextDelete(PortalGetHeapMemory(portal));
+ /*
+ * delete short-term memory context; in the case of a holdable
+ * portal, this has already been done
+ */
+ if (PortalGetHeapMemory(portal))
+ MemoryContextDelete(PortalGetHeapMemory(portal));
+
+ /*
+ * delete long-term memory context; in the case of a non-holdable
+ * portal, this context has never been created, so we don't need to
+ * do anything
+ */
+ if (portal->holdContext)
+ MemoryContextDelete(portal->holdContext);
/* release name and portal data (both are in PortalMemory) */
pfree(portal->name);
@@ -255,7 +316,12 @@ PortalDrop(Portal portal)
}
/*
- * Destroy all portals created in the current transaction (ie, all of them).
+ * Cleanup the portals created in the current transaction. If the
+ * transaction was aborted, all the portals created in this transaction
+ * should be removed. If the transaction was successfully committed, any
+ * holdable cursors created in this transaction need to be kept
+ * open. Only cursors created in the current transaction should be
+ * removed in this fashion.
*
* XXX This assumes that portals can be deleted in a random order, ie,
* no portal has a reference to any other (at least not one that will be
@@ -264,13 +330,17 @@ PortalDrop(Portal portal)
* references...
*/
void
-AtEOXact_portals(void)
+AtEOXact_portals(bool isCommit)
{
HASH_SEQ_STATUS status;
PortalHashEnt *hentry;
+ TransactionId xact = GetCurrentTransactionId();
hash_seq_init(&status, PortalHashTable);
while ((hentry = (PortalHashEnt *) hash_seq_search(&status)) != NULL)
- PortalDrop(hentry->portal);
+ {
+ if (hentry->portal->createXact == xact)
+ PortalDrop(hentry->portal, isCommit);
+ }
}
diff --git a/src/backend/utils/sort/logtape.c b/src/backend/utils/sort/logtape.c
index 1c28028f5f7..643b7a76018 100644
--- a/src/backend/utils/sort/logtape.c
+++ b/src/backend/utils/sort/logtape.c
@@ -64,7 +64,7 @@
* Portions Copyright (c) 1994, Regents of the University of California
*
* IDENTIFICATION
- * $Header: /cvsroot/pgsql/src/backend/utils/sort/logtape.c,v 1.8 2002/06/20 20:29:40 momjian Exp $
+ * $Header: /cvsroot/pgsql/src/backend/utils/sort/logtape.c,v 1.9 2003/03/27 16:51:29 momjian Exp $
*
*-------------------------------------------------------------------------
*/
@@ -470,7 +470,7 @@ LogicalTapeSetCreate(int ntapes)
Assert(ntapes > 0);
lts = (LogicalTapeSet *) palloc(sizeof(LogicalTapeSet) +
(ntapes - 1) *sizeof(LogicalTape *));
- lts->pfile = BufFileCreateTemp();
+ lts->pfile = BufFileCreateTemp(false);
lts->nFileBlocks = 0L;
lts->freeBlocksLen = 32; /* reasonable initial guess */
lts->freeBlocks = (long *) palloc(lts->freeBlocksLen * sizeof(long));
diff --git a/src/backend/utils/sort/tuplestore.c b/src/backend/utils/sort/tuplestore.c
index 65804d5484d..89970b2495b 100644
--- a/src/backend/utils/sort/tuplestore.c
+++ b/src/backend/utils/sort/tuplestore.c
@@ -36,7 +36,7 @@
* Portions Copyright (c) 1994, Regents of the University of California
*
* IDENTIFICATION
- * $Header: /cvsroot/pgsql/src/backend/utils/sort/tuplestore.c,v 1.11 2003/03/09 02:19:13 tgl Exp $
+ * $Header: /cvsroot/pgsql/src/backend/utils/sort/tuplestore.c,v 1.12 2003/03/27 16:51:29 momjian Exp $
*
*-------------------------------------------------------------------------
*/
@@ -65,6 +65,7 @@ struct Tuplestorestate
{
TupStoreStatus status; /* enumerated value as shown above */
bool randomAccess; /* did caller request random access? */
+ bool interTxn; /* keep open through transactions? */
long availMem; /* remaining memory available, in bytes */
BufFile *myfile; /* underlying file, or NULL if none */
@@ -190,7 +191,8 @@ struct Tuplestorestate
static Tuplestorestate *tuplestore_begin_common(bool randomAccess,
- int maxKBytes);
+ bool interTxn,
+ int maxKBytes);
static void dumptuples(Tuplestorestate *state);
static unsigned int getlen(Tuplestorestate *state, bool eofOK);
static void *copytup_heap(Tuplestorestate *state, void *tup);
@@ -205,7 +207,7 @@ static void *readtup_heap(Tuplestorestate *state, unsigned int len);
*/
static Tuplestorestate *
-tuplestore_begin_common(bool randomAccess, int maxKBytes)
+tuplestore_begin_common(bool randomAccess, bool interTxn, int maxKBytes)
{
Tuplestorestate *state;
@@ -213,6 +215,7 @@ tuplestore_begin_common(bool randomAccess, int maxKBytes)
state->status = TSS_INMEM;
state->randomAccess = randomAccess;
+ state->interTxn = interTxn;
state->availMem = maxKBytes * 1024L;
state->myfile = NULL;
@@ -231,10 +234,27 @@ tuplestore_begin_common(bool randomAccess, int maxKBytes)
return state;
}
+/*
+ * tuplestore_begin_heap
+ *
+ * Create a new tuplestore; other types of tuple stores (other than
+ * "heap" tuple stores, for heap tuples) are possible, but not presently
+ * implemented.
+ *
+ * randomAccess: if true, both forward and backward accesses to the
+ * tuple store are allowed.
+ *
+ * interTxn: if true, the files used by on-disk storage persist beyond
+ * the end of the current transaction.
+ *
+ * maxKBytes: how much data to store in memory (any data beyond this
+ * amount is paged to disk).
+ */
Tuplestorestate *
-tuplestore_begin_heap(bool randomAccess, int maxKBytes)
+tuplestore_begin_heap(bool randomAccess, bool interTxn, int maxKBytes)
{
- Tuplestorestate *state = tuplestore_begin_common(randomAccess, maxKBytes);
+ Tuplestorestate *state = tuplestore_begin_common(randomAccess,
+ interTxn, maxKBytes);
state->copytup = copytup_heap;
state->writetup = writetup_heap;
@@ -321,7 +341,7 @@ tuplestore_puttuple(Tuplestorestate *state, void *tuple)
/*
* Nope; time to switch to tape-based operation.
*/
- state->myfile = BufFileCreateTemp();
+ state->myfile = BufFileCreateTemp(state->interTxn);
state->status = TSS_WRITEFILE;
dumptuples(state);
break;
diff --git a/src/include/nodes/parsenodes.h b/src/include/nodes/parsenodes.h
index 49887f450cb..3d4b235e562 100644
--- a/src/include/nodes/parsenodes.h
+++ b/src/include/nodes/parsenodes.h
@@ -7,7 +7,7 @@
* Portions Copyright (c) 1996-2002, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
- * $Id: parsenodes.h,v 1.235 2003/03/20 18:52:48 momjian Exp $
+ * $Id: parsenodes.h,v 1.236 2003/03/27 16:51:29 momjian Exp $
*
*-------------------------------------------------------------------------
*/
@@ -1210,7 +1210,9 @@ typedef struct CommentStmt
*/
#define CURSOR_OPT_BINARY 0x0001
#define CURSOR_OPT_SCROLL 0x0002
-#define CURSOR_OPT_INSENSITIVE 0x0004
+#define CURSOR_OPT_NO_SCROLL 0x0004
+#define CURSOR_OPT_INSENSITIVE 0x0008
+#define CURSOR_OPT_HOLD 0x0010
typedef struct DeclareCursorStmt
{
diff --git a/src/include/storage/buffile.h b/src/include/storage/buffile.h
index 902483a1fb3..c456b74d0f6 100644
--- a/src/include/storage/buffile.h
+++ b/src/include/storage/buffile.h
@@ -18,7 +18,7 @@
* Portions Copyright (c) 1996-2002, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
- * $Id: buffile.h,v 1.12 2002/06/20 20:29:52 momjian Exp $
+ * $Id: buffile.h,v 1.13 2003/03/27 16:51:29 momjian Exp $
*
*-------------------------------------------------------------------------
*/
@@ -34,7 +34,7 @@ typedef struct BufFile BufFile;
* prototypes for functions in buffile.c
*/
-extern BufFile *BufFileCreateTemp(void);
+extern BufFile *BufFileCreateTemp(bool interTxn);
extern void BufFileClose(BufFile *file);
extern size_t BufFileRead(BufFile *file, void *ptr, size_t size);
extern size_t BufFileWrite(BufFile *file, void *ptr, size_t size);
diff --git a/src/include/storage/fd.h b/src/include/storage/fd.h
index a13cec41ea6..261e6314e91 100644
--- a/src/include/storage/fd.h
+++ b/src/include/storage/fd.h
@@ -7,7 +7,7 @@
* Portions Copyright (c) 1996-2002, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
- * $Id: fd.h,v 1.36 2002/08/06 02:36:35 tgl Exp $
+ * $Id: fd.h,v 1.37 2003/03/27 16:51:29 momjian Exp $
*
*-------------------------------------------------------------------------
*/
@@ -55,7 +55,7 @@ extern int max_files_per_process;
/* Operations on virtual Files --- equivalent to Unix kernel file ops */
extern File FileNameOpenFile(FileName fileName, int fileFlags, int fileMode);
extern File PathNameOpenFile(FileName fileName, int fileFlags, int fileMode);
-extern File OpenTemporaryFile(void);
+extern File OpenTemporaryFile(bool keepOverTxn);
extern void FileClose(File file);
extern void FileUnlink(File file);
extern int FileRead(File file, char *buffer, int amount);
diff --git a/src/include/tcop/dest.h b/src/include/tcop/dest.h
index bbad436c049..bbf86ef4ca6 100644
--- a/src/include/tcop/dest.h
+++ b/src/include/tcop/dest.h
@@ -44,7 +44,7 @@
* Portions Copyright (c) 1996-2002, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
- * $Id: dest.h,v 1.32 2002/09/04 20:31:45 momjian Exp $
+ * $Id: dest.h,v 1.33 2003/03/27 16:51:29 momjian Exp $
*
*-------------------------------------------------------------------------
*/
@@ -70,7 +70,8 @@ typedef enum
Remote, /* results sent to frontend process */
RemoteInternal, /* results sent to frontend process in
* internal (binary) form */
- SPI /* results sent to SPI manager */
+ SPI, /* results sent to SPI manager */
+ Tuplestore /* results sent to Tuplestore */
} CommandDest;
/* ----------------
diff --git a/src/include/utils/portal.h b/src/include/utils/portal.h
index c9ca8547ce2..0201b0684c3 100644
--- a/src/include/utils/portal.h
+++ b/src/include/utils/portal.h
@@ -9,7 +9,7 @@
* Portions Copyright (c) 1996-2002, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
- * $Id: portal.h,v 1.39 2003/03/11 19:40:24 tgl Exp $
+ * $Id: portal.h,v 1.40 2003/03/27 16:51:29 momjian Exp $
*
*-------------------------------------------------------------------------
*/
@@ -18,17 +18,45 @@
#include "executor/execdesc.h"
#include "nodes/memnodes.h"
+#include "utils/tuplestore.h"
+/*
+ * We support three kinds of scroll behavior:
+ *
+ * (1) Neither NO SCROLL nor SCROLL was specified: to remain backward
+ * compatible, we allow backward fetches here, unless it would
+ * impose additional runtime overhead to do so.
+ *
+ * (2) NO SCROLL was specified: don't allow any backward fetches.
+ *
+ * (3) SCROLL was specified: allow all kinds of backward fetches, even
+ * if we need to take a slight performance hit to do so.
+ *
+ * Case #1 is converted to #2 or #3 by looking at the query itself and
+ * determining if scrollability can be supported without additional
+ * overhead.
+ */
+typedef enum
+{
+ DEFAULT_SCROLL,
+ DISABLE_SCROLL,
+ ENABLE_SCROLL
+} ScrollType;
typedef struct PortalData *Portal;
typedef struct PortalData
{
char *name; /* Portal's name */
- MemoryContext heap; /* subsidiary memory */
+ MemoryContext heap; /* memory for storing short-term data */
QueryDesc *queryDesc; /* Info about query associated with portal */
void (*cleanup) (Portal); /* Cleanup routine (optional) */
- bool backwardOK; /* is fetch backwards allowed? */
+ ScrollType scrollType; /* Allow backward fetches? */
+ bool holdOpen; /* hold open after txn ends? */
+ TransactionId createXact; /* the xid of the creating txn */
+ Tuplestorestate *holdStore; /* store for holdable cursors */
+ MemoryContext holdContext; /* memory for long-term data */
+
/*
* atStart, atEnd and portalPos indicate the current cursor position.
* portalPos is zero before the first row, N after fetching N'th row of
@@ -58,11 +86,12 @@ typedef struct PortalData
extern void EnablePortalManager(void);
-extern void AtEOXact_portals(void);
+extern void AtEOXact_portals(bool isCommit);
extern Portal CreatePortal(const char *name);
-extern void PortalDrop(Portal portal);
+extern void PortalDrop(Portal portal, bool persistHoldable);
extern Portal GetPortalByName(const char *name);
extern void PortalSetQuery(Portal portal, QueryDesc *queryDesc,
void (*cleanup) (Portal portal));
+extern void PersistHoldablePortal(Portal portal);
#endif /* PORTAL_H */
diff --git a/src/include/utils/tuplestore.h b/src/include/utils/tuplestore.h
index 76fe9fb4287..dbc47ef29d6 100644
--- a/src/include/utils/tuplestore.h
+++ b/src/include/utils/tuplestore.h
@@ -17,7 +17,7 @@
* Portions Copyright (c) 1996-2002, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
- * $Id: tuplestore.h,v 1.9 2003/03/09 03:34:10 tgl Exp $
+ * $Id: tuplestore.h,v 1.10 2003/03/27 16:51:29 momjian Exp $
*
*-------------------------------------------------------------------------
*/
@@ -37,7 +37,8 @@ typedef struct Tuplestorestate Tuplestorestate;
*/
extern Tuplestorestate *tuplestore_begin_heap(bool randomAccess,
- int maxKBytes);
+ bool interTxn,
+ int maxKBytes);
extern void tuplestore_puttuple(Tuplestorestate *state, void *tuple);
diff --git a/src/pl/plpgsql/src/pl_exec.c b/src/pl/plpgsql/src/pl_exec.c
index d105c0e8dcc..d2e05f16c26 100644
--- a/src/pl/plpgsql/src/pl_exec.c
+++ b/src/pl/plpgsql/src/pl_exec.c
@@ -3,7 +3,7 @@
* procedural language
*
* IDENTIFICATION
- * $Header: /cvsroot/pgsql/src/pl/plpgsql/src/pl_exec.c,v 1.83 2003/03/25 03:16:40 tgl Exp $
+ * $Header: /cvsroot/pgsql/src/pl/plpgsql/src/pl_exec.c,v 1.84 2003/03/27 16:51:29 momjian Exp $
*
* This software is copyrighted by Jan Wieck - Hamburg.
*
@@ -1757,7 +1757,7 @@ exec_init_tuple_store(PLpgSQL_execstate * estate)
estate->tuple_store_cxt = rsi->econtext->ecxt_per_query_memory;
oldcxt = MemoryContextSwitchTo(estate->tuple_store_cxt);
- estate->tuple_store = tuplestore_begin_heap(true, SortMem);
+ estate->tuple_store = tuplestore_begin_heap(true, false, SortMem);
MemoryContextSwitchTo(oldcxt);
estate->rettupdesc = rsi->expectedDesc;
diff --git a/src/test/regress/expected/portals.out b/src/test/regress/expected/portals.out
index 23c186cead1..7520653924e 100644
--- a/src/test/regress/expected/portals.out
+++ b/src/test/regress/expected/portals.out
@@ -1,30 +1,30 @@
--
--- PORTALS
+-- Cursor regression tests
--
BEGIN;
-DECLARE foo1 CURSOR FOR SELECT * FROM tenk1;
-DECLARE foo2 CURSOR FOR SELECT * FROM tenk2;
-DECLARE foo3 CURSOR FOR SELECT * FROM tenk1;
-DECLARE foo4 CURSOR FOR SELECT * FROM tenk2;
-DECLARE foo5 CURSOR FOR SELECT * FROM tenk1;
-DECLARE foo6 CURSOR FOR SELECT * FROM tenk2;
-DECLARE foo7 CURSOR FOR SELECT * FROM tenk1;
-DECLARE foo8 CURSOR FOR SELECT * FROM tenk2;
-DECLARE foo9 CURSOR FOR SELECT * FROM tenk1;
-DECLARE foo10 CURSOR FOR SELECT * FROM tenk2;
-DECLARE foo11 CURSOR FOR SELECT * FROM tenk1;
-DECLARE foo12 CURSOR FOR SELECT * FROM tenk2;
-DECLARE foo13 CURSOR FOR SELECT * FROM tenk1;
-DECLARE foo14 CURSOR FOR SELECT * FROM tenk2;
-DECLARE foo15 CURSOR FOR SELECT * FROM tenk1;
-DECLARE foo16 CURSOR FOR SELECT * FROM tenk2;
-DECLARE foo17 CURSOR FOR SELECT * FROM tenk1;
-DECLARE foo18 CURSOR FOR SELECT * FROM tenk2;
-DECLARE foo19 CURSOR FOR SELECT * FROM tenk1;
-DECLARE foo20 CURSOR FOR SELECT * FROM tenk2;
-DECLARE foo21 CURSOR FOR SELECT * FROM tenk1;
-DECLARE foo22 CURSOR FOR SELECT * FROM tenk2;
-DECLARE foo23 CURSOR FOR SELECT * FROM tenk1;
+DECLARE foo1 SCROLL CURSOR FOR SELECT * FROM tenk1;
+DECLARE foo2 SCROLL CURSOR FOR SELECT * FROM tenk2;
+DECLARE foo3 SCROLL CURSOR FOR SELECT * FROM tenk1;
+DECLARE foo4 SCROLL CURSOR FOR SELECT * FROM tenk2;
+DECLARE foo5 SCROLL CURSOR FOR SELECT * FROM tenk1;
+DECLARE foo6 SCROLL CURSOR FOR SELECT * FROM tenk2;
+DECLARE foo7 SCROLL CURSOR FOR SELECT * FROM tenk1;
+DECLARE foo8 SCROLL CURSOR FOR SELECT * FROM tenk2;
+DECLARE foo9 SCROLL CURSOR FOR SELECT * FROM tenk1;
+DECLARE foo10 SCROLL CURSOR FOR SELECT * FROM tenk2;
+DECLARE foo11 SCROLL CURSOR FOR SELECT * FROM tenk1;
+DECLARE foo12 SCROLL CURSOR FOR SELECT * FROM tenk2;
+DECLARE foo13 SCROLL CURSOR FOR SELECT * FROM tenk1;
+DECLARE foo14 SCROLL CURSOR FOR SELECT * FROM tenk2;
+DECLARE foo15 SCROLL CURSOR FOR SELECT * FROM tenk1;
+DECLARE foo16 SCROLL CURSOR FOR SELECT * FROM tenk2;
+DECLARE foo17 SCROLL CURSOR FOR SELECT * FROM tenk1;
+DECLARE foo18 SCROLL CURSOR FOR SELECT * FROM tenk2;
+DECLARE foo19 SCROLL CURSOR FOR SELECT * FROM tenk1;
+DECLARE foo20 SCROLL CURSOR FOR SELECT * FROM tenk2;
+DECLARE foo21 SCROLL CURSOR FOR SELECT * FROM tenk1;
+DECLARE foo22 SCROLL CURSOR FOR SELECT * FROM tenk2;
+DECLARE foo23 SCROLL CURSOR FOR SELECT * FROM tenk1;
FETCH 1 in foo1;
unique1 | unique2 | two | four | ten | twenty | hundred | thousand | twothousand | fivethous | tenthous | odd | even | stringu1 | stringu2 | string4
---------+---------+-----+------+-----+--------+---------+----------+-------------+-----------+----------+-----+------+----------+----------+---------
@@ -675,4 +675,66 @@ CLOSE foo9;
CLOSE foo10;
CLOSE foo11;
CLOSE foo12;
-end;
+-- is there a reason why we don't close the rest of the open cursors?
+END;
+--
+-- NO SCROLL disallows backward fetching
+--
+BEGIN;
+DECLARE foo24 NO SCROLL CURSOR FOR SELECT * FROM tenk1;
+FETCH 1 FROM foo24;
+ unique1 | unique2 | two | four | ten | twenty | hundred | thousand | twothousand | fivethous | tenthous | odd | even | stringu1 | stringu2 | string4
+---------+---------+-----+------+-----+--------+---------+----------+-------------+-----------+----------+-----+------+----------+----------+---------
+ 8800 | 0 | 0 | 0 | 0 | 0 | 0 | 800 | 800 | 3800 | 8800 | 0 | 1 | MAAAAA | AAAAAA | AAAAxx
+(1 row)
+
+FETCH BACKWARD 1 FROM foo24; -- should fail
+ERROR: Cursor can only scan forward
+ Declare it with SCROLL option to enable backward scan
+END;
+--
+-- Cursors outside transaction blocks
+--
+BEGIN;
+DECLARE foo25 SCROLL CURSOR WITH HOLD FOR SELECT * FROM tenk2;
+FETCH FROM foo25;
+ unique1 | unique2 | two | four | ten | twenty | hundred | thousand | twothousand | fivethous | tenthous | odd | even | stringu1 | stringu2 | string4
+---------+---------+-----+------+-----+--------+---------+----------+-------------+-----------+----------+-----+------+----------+----------+---------
+ 8800 | 0 | 0 | 0 | 0 | 0 | 0 | 800 | 800 | 3800 | 8800 | 0 | 1 | MAAAAA | AAAAAA | AAAAxx
+(1 row)
+
+FETCH FROM foo25;
+ unique1 | unique2 | two | four | ten | twenty | hundred | thousand | twothousand | fivethous | tenthous | odd | even | stringu1 | stringu2 | string4
+---------+---------+-----+------+-----+--------+---------+----------+-------------+-----------+----------+-----+------+----------+----------+---------
+ 1891 | 1 | 1 | 3 | 1 | 11 | 91 | 891 | 1891 | 1891 | 1891 | 182 | 183 | TUAAAA | BAAAAA | HHHHxx
+(1 row)
+
+COMMIT;
+FETCH FROM foo25;
+ unique1 | unique2 | two | four | ten | twenty | hundred | thousand | twothousand | fivethous | tenthous | odd | even | stringu1 | stringu2 | string4
+---------+---------+-----+------+-----+--------+---------+----------+-------------+-----------+----------+-----+------+----------+----------+---------
+ 3420 | 2 | 0 | 0 | 0 | 0 | 20 | 420 | 1420 | 3420 | 3420 | 40 | 41 | OBAAAA | CAAAAA | OOOOxx
+(1 row)
+
+FETCH BACKWARD FROM foo25;
+ unique1 | unique2 | two | four | ten | twenty | hundred | thousand | twothousand | fivethous | tenthous | odd | even | stringu1 | stringu2 | string4
+---------+---------+-----+------+-----+--------+---------+----------+-------------+-----------+----------+-----+------+----------+----------+---------
+ 1891 | 1 | 1 | 3 | 1 | 11 | 91 | 891 | 1891 | 1891 | 1891 | 182 | 183 | TUAAAA | BAAAAA | HHHHxx
+(1 row)
+
+FETCH ABSOLUTE -1 FROM foo25;
+ unique1 | unique2 | two | four | ten | twenty | hundred | thousand | twothousand | fivethous | tenthous | odd | even | stringu1 | stringu2 | string4
+---------+---------+-----+------+-----+--------+---------+----------+-------------+-----------+----------+-----+------+----------+----------+---------
+ 2968 | 9999 | 0 | 0 | 8 | 8 | 68 | 968 | 968 | 2968 | 2968 | 136 | 137 | EKAAAA | PUOAAA | VVVVxx
+(1 row)
+
+CLOSE foo25;
+--
+-- ROLLBACK should close holdable cursors
+--
+BEGIN;
+DECLARE foo26 CURSOR WITH HOLD FOR SELECT * FROM tenk1;
+ROLLBACK;
+-- should fail
+FETCH FROM foo26;
+WARNING: PerformPortalFetch: portal "foo26" not found
diff --git a/src/test/regress/sql/portals.sql b/src/test/regress/sql/portals.sql
index c4e257ef2d0..2df820a30a7 100644
--- a/src/test/regress/sql/portals.sql
+++ b/src/test/regress/sql/portals.sql
@@ -1,54 +1,54 @@
--
--- PORTALS
+-- Cursor regression tests
--
BEGIN;
-DECLARE foo1 CURSOR FOR SELECT * FROM tenk1;
+DECLARE foo1 SCROLL CURSOR FOR SELECT * FROM tenk1;
-DECLARE foo2 CURSOR FOR SELECT * FROM tenk2;
+DECLARE foo2 SCROLL CURSOR FOR SELECT * FROM tenk2;
-DECLARE foo3 CURSOR FOR SELECT * FROM tenk1;
+DECLARE foo3 SCROLL CURSOR FOR SELECT * FROM tenk1;
-DECLARE foo4 CURSOR FOR SELECT * FROM tenk2;
+DECLARE foo4 SCROLL CURSOR FOR SELECT * FROM tenk2;
-DECLARE foo5 CURSOR FOR SELECT * FROM tenk1;
+DECLARE foo5 SCROLL CURSOR FOR SELECT * FROM tenk1;
-DECLARE foo6 CURSOR FOR SELECT * FROM tenk2;
+DECLARE foo6 SCROLL CURSOR FOR SELECT * FROM tenk2;
-DECLARE foo7 CURSOR FOR SELECT * FROM tenk1;
+DECLARE foo7 SCROLL CURSOR FOR SELECT * FROM tenk1;
-DECLARE foo8 CURSOR FOR SELECT * FROM tenk2;
+DECLARE foo8 SCROLL CURSOR FOR SELECT * FROM tenk2;
-DECLARE foo9 CURSOR FOR SELECT * FROM tenk1;
+DECLARE foo9 SCROLL CURSOR FOR SELECT * FROM tenk1;
-DECLARE foo10 CURSOR FOR SELECT * FROM tenk2;
+DECLARE foo10 SCROLL CURSOR FOR SELECT * FROM tenk2;
-DECLARE foo11 CURSOR FOR SELECT * FROM tenk1;
+DECLARE foo11 SCROLL CURSOR FOR SELECT * FROM tenk1;
-DECLARE foo12 CURSOR FOR SELECT * FROM tenk2;
+DECLARE foo12 SCROLL CURSOR FOR SELECT * FROM tenk2;
-DECLARE foo13 CURSOR FOR SELECT * FROM tenk1;
+DECLARE foo13 SCROLL CURSOR FOR SELECT * FROM tenk1;
-DECLARE foo14 CURSOR FOR SELECT * FROM tenk2;
+DECLARE foo14 SCROLL CURSOR FOR SELECT * FROM tenk2;
-DECLARE foo15 CURSOR FOR SELECT * FROM tenk1;
+DECLARE foo15 SCROLL CURSOR FOR SELECT * FROM tenk1;
-DECLARE foo16 CURSOR FOR SELECT * FROM tenk2;
+DECLARE foo16 SCROLL CURSOR FOR SELECT * FROM tenk2;
-DECLARE foo17 CURSOR FOR SELECT * FROM tenk1;
+DECLARE foo17 SCROLL CURSOR FOR SELECT * FROM tenk1;
-DECLARE foo18 CURSOR FOR SELECT * FROM tenk2;
+DECLARE foo18 SCROLL CURSOR FOR SELECT * FROM tenk2;
-DECLARE foo19 CURSOR FOR SELECT * FROM tenk1;
+DECLARE foo19 SCROLL CURSOR FOR SELECT * FROM tenk1;
-DECLARE foo20 CURSOR FOR SELECT * FROM tenk2;
+DECLARE foo20 SCROLL CURSOR FOR SELECT * FROM tenk2;
-DECLARE foo21 CURSOR FOR SELECT * FROM tenk1;
+DECLARE foo21 SCROLL CURSOR FOR SELECT * FROM tenk1;
-DECLARE foo22 CURSOR FOR SELECT * FROM tenk2;
+DECLARE foo22 SCROLL CURSOR FOR SELECT * FROM tenk2;
-DECLARE foo23 CURSOR FOR SELECT * FROM tenk1;
+DECLARE foo23 SCROLL CURSOR FOR SELECT * FROM tenk1;
FETCH 1 in foo1;
@@ -166,5 +166,55 @@ CLOSE foo11;
CLOSE foo12;
-end;
+-- is there a reason why we don't close the rest of the open cursors?
+END;
+
+--
+-- NO SCROLL disallows backward fetching
+--
+
+BEGIN;
+
+DECLARE foo24 NO SCROLL CURSOR FOR SELECT * FROM tenk1;
+
+FETCH 1 FROM foo24;
+
+FETCH BACKWARD 1 FROM foo24; -- should fail
+
+END;
+
+--
+-- Cursors outside transaction blocks
+--
+
+BEGIN;
+
+DECLARE foo25 SCROLL CURSOR WITH HOLD FOR SELECT * FROM tenk2;
+
+FETCH FROM foo25;
+
+FETCH FROM foo25;
+
+COMMIT;
+
+FETCH FROM foo25;
+
+FETCH BACKWARD FROM foo25;
+
+FETCH ABSOLUTE -1 FROM foo25;
+
+CLOSE foo25;
+
+--
+-- ROLLBACK should close holdable cursors
+--
+
+BEGIN;
+
+DECLARE foo26 CURSOR WITH HOLD FOR SELECT * FROM tenk1;
+
+ROLLBACK;
+
+-- should fail
+FETCH FROM foo26;
\ No newline at end of file
--
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