From bc8a1fc282005f6da9ff7650eadc65b160077e43 Mon Sep 17 00:00:00 2001
From: Joe Conway <mail@joeconway.com>
Date: Wed, 11 Aug 2004 00:49:35 +0000
Subject: [PATCH] Hashed crosstab was dying with an SPI_finish error when the
source SQL produced no rows. Now it returns 0 rows instead. Adjusted
regression test for this case.
---
contrib/tablefunc/expected/tablefunc.out | 20 +++++++++++++++++++-
contrib/tablefunc/sql/tablefunc.sql | 11 +++++++++++
contrib/tablefunc/tablefunc.c | 23 +++++++++--------------
3 files changed, 39 insertions(+), 15 deletions(-)
diff --git a/contrib/tablefunc/expected/tablefunc.out b/contrib/tablefunc/expected/tablefunc.out
index 281de5d2663..d8f4c30a5dc 100644
--- a/contrib/tablefunc/expected/tablefunc.out
+++ b/contrib/tablefunc/expected/tablefunc.out
@@ -127,7 +127,7 @@ SELECT * FROM crosstab('SELECT rowid, attribute, val FROM ct where rowclass = ''
-- hash based crosstab
--
create table cth(id serial, rowid text, rowdt timestamp, attribute text, val text);
-NOTICE: CREATE TABLE will create implicit sequence "cth_id_seq" for "serial" column "cth.id"
+NOTICE: CREATE TABLE will create implicit sequence "cth_id_seq" for serial column "cth.id"
insert into cth values(DEFAULT,'test1','01 March 2003','temperature','42');
insert into cth values(DEFAULT,'test1','01 March 2003','test_result','PASS');
-- the next line is intentionally left commented and is therefore a "missing" attribute
@@ -193,6 +193,24 @@ SELECT * FROM crosstab(
'SELECT DISTINCT rowdt, attribute FROM cth ORDER BY 2')
AS c(rowid text, rowdt timestamp, temperature int4, test_result text, test_startdate timestamp, volts float8);
ERROR: provided "categories" SQL must return 1 column of at least one row
+-- if source query returns zero rows, get zero rows returned
+SELECT * FROM crosstab(
+ 'SELECT rowid, rowdt, attribute, val FROM cth WHERE false ORDER BY 1',
+ 'SELECT DISTINCT attribute FROM cth ORDER BY 1')
+AS c(rowid text, rowdt timestamp, temperature text, test_result text, test_startdate text, volts text);
+ rowid | rowdt | temperature | test_result | test_startdate | volts
+-------+-------+-------------+-------------+----------------+-------
+(0 rows)
+
+-- if source query returns zero rows, get zero rows returned even if category query generates no rows
+SELECT * FROM crosstab(
+ 'SELECT rowid, rowdt, attribute, val FROM cth WHERE false ORDER BY 1',
+ 'SELECT DISTINCT attribute FROM cth WHERE false ORDER BY 1')
+AS c(rowid text, rowdt timestamp, temperature text, test_result text, test_startdate text, volts text);
+ rowid | rowdt | temperature | test_result | test_startdate | volts
+-------+-------+-------------+-------------+----------------+-------
+(0 rows)
+
--
-- connectby
--
diff --git a/contrib/tablefunc/sql/tablefunc.sql b/contrib/tablefunc/sql/tablefunc.sql
index 5292fc2bc78..c464acbd3b4 100644
--- a/contrib/tablefunc/sql/tablefunc.sql
+++ b/contrib/tablefunc/sql/tablefunc.sql
@@ -88,6 +88,17 @@ SELECT * FROM crosstab(
'SELECT DISTINCT rowdt, attribute FROM cth ORDER BY 2')
AS c(rowid text, rowdt timestamp, temperature int4, test_result text, test_startdate timestamp, volts float8);
+-- if source query returns zero rows, get zero rows returned
+SELECT * FROM crosstab(
+ 'SELECT rowid, rowdt, attribute, val FROM cth WHERE false ORDER BY 1',
+ 'SELECT DISTINCT attribute FROM cth ORDER BY 1')
+AS c(rowid text, rowdt timestamp, temperature text, test_result text, test_startdate text, volts text);
+
+-- if source query returns zero rows, get zero rows returned even if category query generates no rows
+SELECT * FROM crosstab(
+ 'SELECT rowid, rowdt, attribute, val FROM cth WHERE false ORDER BY 1',
+ 'SELECT DISTINCT attribute FROM cth WHERE false ORDER BY 1')
+AS c(rowid text, rowdt timestamp, temperature text, test_result text, test_startdate text, volts text);
--
-- connectby
diff --git a/contrib/tablefunc/tablefunc.c b/contrib/tablefunc/tablefunc.c
index 3eccebf476f..f14c3963026 100644
--- a/contrib/tablefunc/tablefunc.c
+++ b/contrib/tablefunc/tablefunc.c
@@ -821,15 +821,6 @@ load_categories_hash(char *cats_sql, MemoryContext per_query_ctx)
MemoryContextSwitchTo(SPIcontext);
}
}
- else
- {
- /* no qualifying tuples */
- SPI_finish();
- ereport(ERROR,
- (errcode(ERRCODE_SYNTAX_ERROR),
- errmsg("provided \"categories\" SQL must " \
- "return 1 column of at least one row")));
- }
if (SPI_finish() != SPI_OK_FINISH)
/* internal error */
@@ -879,6 +870,15 @@ get_crosstab_tuplestore(char *sql,
j;
int result_ncols;
+ if (num_categories == 0)
+ {
+ /* no qualifying category tuples */
+ ereport(ERROR,
+ (errcode(ERRCODE_SYNTAX_ERROR),
+ errmsg("provided \"categories\" SQL must " \
+ "return 1 column of at least one row")));
+ }
+
/*
* The provided SQL query must always return at least three
* columns:
@@ -994,11 +994,6 @@ get_crosstab_tuplestore(char *sql,
MemoryContextSwitchTo(SPIcontext);
}
- else
- {
- /* no qualifying tuples */
- SPI_finish();
- }
if (SPI_finish() != SPI_OK_FINISH)
/* internal error */
--
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