From 26e0321191d85ad2ce2aedca9914bca808d0d7e7 Mon Sep 17 00:00:00 2001
From: Bruce Momjian <bruce@momjian.us>
Date: Wed, 17 Jan 2001 06:41:31 +0000
Subject: [PATCH] Move structure comments from the top block down to the line
entries for this file to match all the other files, and to be clearer.
---
src/backend/optimizer/README | 2 +-
src/include/nodes/primnodes.h | 290 ++++++++++++++--------------------
2 files changed, 121 insertions(+), 171 deletions(-)
diff --git a/src/backend/optimizer/README b/src/backend/optimizer/README
index 49450ff1fb3..520ab1b2421 100644
--- a/src/backend/optimizer/README
+++ b/src/backend/optimizer/README
@@ -80,7 +80,7 @@ example, the WHERE clause "tab1.col1 = tab2.col1" generates a JoinInfo
for tab1 listing tab2 as an unjoined relation, and also one for tab2
showing tab1 as an unjoined relation.
-If we have only a single base relation in the query, we are done now.
+If we have only a single base relation in the query, we are done.
Otherwise we have to figure out how to join the base relations into a
single join relation.
diff --git a/src/include/nodes/primnodes.h b/src/include/nodes/primnodes.h
index 62b65fee8b0..4cfda0d2ffd 100644
--- a/src/include/nodes/primnodes.h
+++ b/src/include/nodes/primnodes.h
@@ -10,7 +10,7 @@
* Portions Copyright (c) 1996-2000, PostgreSQL, Inc
* Portions Copyright (c) 1994, Regents of the University of California
*
- * $Id: primnodes.h,v 1.49 2000/09/29 18:21:39 tgl Exp $
+ * $Id: primnodes.h,v 1.50 2001/01/17 06:41:31 momjian Exp $
*
*-------------------------------------------------------------------------
*/
@@ -29,17 +29,8 @@ typedef struct FunctionCache *FunctionCachePtr;
* ----------------------------------------------------------------
*/
-/* ----------------
+/*
* Resdom (Result Domain)
- * resno - attribute number
- * restype - type of the value
- * restypmod - type-specific modifier of the value
- * resname - name of the resdom (could be NULL)
- * ressortgroupref - nonzero if referenced by a sort/group clause
- * reskey - order of key in a sort (for those > 0)
- * reskeyop - sort operator's regproc Oid
- * resjunk - set to true to eliminate the attribute
- * from final target list
*
* Notes:
* ressortgroupref is the parse/plan-time representation of ORDER BY and
@@ -59,46 +50,48 @@ typedef struct FunctionCache *FunctionCachePtr;
*
* Both reskey and reskeyop are typically zero during parse/plan stages.
* The executor does not pay any attention to ressortgroupref.
- * ----------------
+ *
*/
typedef struct Resdom
{
- NodeTag type;
- AttrNumber resno;
- Oid restype;
- int32 restypmod;
- char *resname;
+ NodeTag type;
+ AttrNumber resno; /* attribute number */
+ Oid restype; /* type of the value */
+ int32 restypmod; /* type-specific modifier of the value */
+ char *resname; /* name of the resdom (could be NULL) */
Index ressortgroupref;
- Index reskey;
- Oid reskeyop;
- bool resjunk;
+ /* nonzero if referenced by a sort/group clause */
+ Index reskey; /* order of key in a sort (for those > 0) */
+ Oid reskeyop; /* sort operator's regproc Oid */
+ bool resjunk; /* set to true to eliminate the attribute
+ * from final target list */
} Resdom;
-/* -------------
+/*
* Fjoin
- * initialized - true if the Fjoin has already been initialized for
- * the current target list evaluation
- * nNodes - The number of Iter nodes returning sets that the
- * node will flatten
- * outerList - 1 or more Iter nodes
- * inner - exactly one Iter node. We eval every node in the
- * outerList once then eval the inner node to completion
- * pair the outerList result vector with each inner
- * result to form the full result. When the inner has
- * been exhausted, we get the next outer result vector
- * and reset the inner.
- * results - The complete (flattened) result vector
- * alwaysNull - a null vector to indicate sets with a cardinality of
- * 0, we treat them as the set {NULL}.
*/
typedef struct Fjoin
{
NodeTag type;
- bool fj_initialized;
- int fj_nNodes;
- List *fj_innerNode;
- DatumPtr fj_results;
- BoolPtr fj_alwaysDone;
+ bool fj_initialized; /* true if the Fjoin has already been
+ * initialized for the current target
+ * list evaluation */
+ int fj_nNodes; /* The number of Iter nodes returning
+ * sets that the node will flatten */
+ List *fj_innerNode; /* exactly one Iter node. We eval every
+ * node in the outerList once then eval
+ * the inner node to completion pair the
+ * outerList result vector with each inner
+ * result to form the full result. When
+ * the inner has been exhausted, we get
+ * the next outer result vector and reset
+ * the inner.
+ */
+ DatumPtr fj_results; /* The complete (flattened) result vector */
+ BoolPtr fj_alwaysDone; /* a null vector to indicate sets with a
+ * cardinality of 0, we treat them as the
+ * set {NULL}.
+ */
} Fjoin;
@@ -107,13 +100,8 @@ typedef struct Fjoin
* ----------------------------------------------------------------
*/
-/* ----------------
+/*
* Expr
- * typeOid - oid of the type of this expression
- * opType - type of this expression
- * oper - operator node if needed (Oper, Func, or SubPlan)
- * args - arguments to this expression
- * ----------------
*/
typedef enum OpType
{
@@ -123,23 +111,15 @@ typedef enum OpType
typedef struct Expr
{
NodeTag type;
- Oid typeOid; /* oid of the type of this expr */
- OpType opType; /* type of the op */
- Node *oper; /* could be Oper or Func or SubPlan */
- List *args; /* list of argument nodes */
+ Oid typeOid; /* oid of the type of this expression */
+ OpType opType; /* type of this expression */
+ Node *oper; /* operator node if needed (Oper, Func, or
+ * SubPlan) */
+ List *args; /* arguments to this expression */
} Expr;
-/* ----------------
+/*
* Var
- * varno - index of this var's relation in the range table
- * (could also be INNER or OUTER)
- * varattno - attribute number of this var, or zero for all
- * vartype - pg_type tuple OID for the type of this var
- * vartypmod - pg_attribute typmod value
- * varlevelsup - for subquery variables referencing outer relations;
- * 0 in a normal var, >0 means N levels up
- * varnoold - original value of varno
- * varoattno - original value of varattno
*
* Note: during parsing/planning, varnoold/varoattno are always just copies
* of varno/varattno. At the tail end of planning, Var nodes appearing in
@@ -160,23 +140,22 @@ typedef struct Expr
typedef struct Var
{
NodeTag type;
- Index varno;
- AttrNumber varattno;
- Oid vartype;
- int32 vartypmod;
+ Index varno; /* index of this var's relation in the range
+ * table (could also be INNER or OUTER) */
+ AttrNumber varattno; /* attribute number of this var, or zero for all */
+ Oid vartype; /* pg_type tuple OID for the type of this var */
+ int32 vartypmod; /* pg_attribute typmod value */
Index varlevelsup;
- Index varnoold; /* mainly for debugging --- see above */
- AttrNumber varoattno;
+ /* for subquery variables referencing outer
+ * relations; 0 in a normal var, >0 means N
+ * levels up */
+ Index varnoold; /* original value of varno, for debugging */
+ AttrNumber varoattno; /* original value of varattno */
} Var;
-/* ----------------
+/*
* Oper
- * opno - PG_OPERATOR OID of the operator
- * opid - PG_PROC OID for the operator's underlying function
- * opresulttype - PG_TYPE OID of the operator's return value
- * op_fcache - runtime state while running the function
*
- * ----
* NOTE: in the good old days 'opno' used to be both (or either, or
* neither) the pg_operator oid, and/or the pg_proc oid depending
* on the postgres module in question (parser->pg_operator,
@@ -190,43 +169,40 @@ typedef struct Var
* Note also that opid is not necessarily filled in immediately on creation
* of the node. The planner makes sure it is valid before passing the node
* tree to the executor, but during parsing/planning opid is typically 0.
- * ----------------
+ *
*/
typedef struct Oper
{
NodeTag type;
- Oid opno;
- Oid opid;
+ Oid opno; /* PG_OPERATOR OID of the operator */
+ Oid opid; /* PG_PROC OID for the operator's underlying
+ * function */
Oid opresulttype;
+ /* PG_TYPE OID of the operator's return value */
FunctionCachePtr op_fcache;
+ /* runtime state while running the function */
} Oper;
-/* ----------------
+/*
* Const
- * consttype - PG_TYPE OID of the constant's value
- * constlen - length in bytes of the constant's value
- * constvalue - the constant's value
- * constisnull - whether the constant is null
- * (if true, the other fields are undefined)
- * constbyval - whether the information in constvalue
- * if passed by value. If true, then all the information
- * is stored in the datum. If false, then the datum
- * contains a pointer to the information.
- * constisset - whether the const represents a set. The const
- * value corresponding will be the query that defines
- * the set.
- * ----------------
*/
typedef struct Const
{
NodeTag type;
- Oid consttype;
- int constlen;
- Datum constvalue;
- bool constisnull;
- bool constbyval;
- bool constisset;
+ Oid consttype; /* PG_TYPE OID of the constant's value */
+ int constlen; /* length in bytes of the constant's value */
+ Datum constvalue; /* the constant's value */
+ bool constisnull; /* whether the constant is null (if true,
+ * the other fields are undefined) */
+ bool constbyval; /* whether the information in constvalue
+ * if passed by value. If true, then all
+ * the information is stored in the datum.
+ * If false, then the datum contains a pointer
+ * to the information. */
+ bool constisset; /* whether the const represents a set.
+ * The const value corresponding will be the
+ * query that defines the set. */
bool constiscast;
} Const;
@@ -250,38 +226,33 @@ typedef struct Const
*
* PARAM_OLD: Same as PARAM_NEW, but in this case we refer to
* the "OLD" tuple.
- *
- * paramid - numeric identifier for literal-constant parameters ("$1")
- * paramname - attribute name for tuple-substitution parameters ("$.foo")
- * paramtype - PG_TYPE OID of the parameter's value
* ----------------
*/
typedef struct Param
{
NodeTag type;
- int paramkind;
- AttrNumber paramid;
- char *paramname;
- Oid paramtype;
+ int paramkind; /* specifies the kind of parameter. See above */
+ AttrNumber paramid; /* numeric identifier for literal-constant
+ * parameters ("$1") */
+ char *paramname; /* attribute name for tuple-substitution
+ * parameters ("$.foo") */
+ Oid paramtype; /* PG_TYPE OID of the parameter's value */
} Param;
-/* ----------------
+/*
* Func
- * funcid - PG_PROC OID of the function
- * functype - PG_TYPE OID of the function's return value
- * func_fcache - runtime state while running this function. Where
- * we are in the execution of the function if it
- * returns more than one value, etc.
- * See utils/fcache.h
- * ----------------
*/
typedef struct Func
{
NodeTag type;
- Oid funcid;
- Oid functype;
+ Oid funcid; /* PG_PROC OID of the function */
+ Oid functype; /* PG_TYPE OID of the function's return value */
FunctionCachePtr func_fcache;
+ /* runtime state while running this function.
+ * Where we are in the execution of the function
+ * if it returns more than one value, etc.
+ * See utils/fcache.h */
} Func;
/* ----------------
@@ -298,36 +269,24 @@ typedef struct Iter
* checking) */
} Iter;
-/* ----------------
+/*
* Aggref
- * aggname - name of the aggregate
- * basetype - base type Oid of the aggregate (ie, input type)
- * aggtype - type Oid of final result of the aggregate
- * target - attribute or expression we are aggregating on
- * aggstar - TRUE if argument was really '*'
- * aggdistinct - TRUE if it's agg(DISTINCT ...)
- * aggno - workspace for executor (see nodeAgg.c)
- * ----------------
*/
typedef struct Aggref
{
NodeTag type;
- char *aggname;
- Oid basetype;
- Oid aggtype;
- Node *target;
- bool aggstar;
- bool aggdistinct;
- int aggno;
+ char *aggname; /* name of the aggregate */
+ Oid basetype; /* base type Oid of the aggregate
+ * (ie, input type) */
+ Oid aggtype; /* type Oid of final result of the aggregate */
+ Node *target; /* attribute or expression we are aggregating on */
+ bool aggstar; /* TRUE if argument was really '*' */
+ bool aggdistinct;/* TRUE if it's agg(DISTINCT ...) */
+ int aggno; /* workspace for executor (see nodeAgg.c) */
} Aggref;
/* ----------------
* SubLink
- * subLinkType - EXISTS, ALL, ANY, MULTIEXPR, EXPR
- * useor - TRUE to combine column results with "OR" not "AND"
- * lefthand - list of outer-query expressions on the left
- * oper - list of Oper nodes for combining operators
- * subselect - subselect as Query* or parsetree
*
* A SubLink represents a subselect appearing in an expression, and in some
* cases also the combining operator(s) just above it. The subLinkType
@@ -385,11 +344,12 @@ typedef enum SubLinkType
typedef struct SubLink
{
NodeTag type;
- SubLinkType subLinkType;
- bool useor;
- List *lefthand;
- List *oper;
- Node *subselect;
+ SubLinkType subLinkType;/* EXISTS, ALL, ANY, MULTIEXPR, EXPR */
+ bool useor; /* TRUE to combine column results with "OR"
+ * not "AND" */
+ List *lefthand; /* list of outer-query expressions on the left */
+ List *oper; /* list of Oper nodes for combining operators */
+ Node *subselect; /* subselect as Query* or parsetree */
} SubLink;
/* ----------------
@@ -402,15 +362,6 @@ typedef struct SubLink
* appropriate part of the array; the result of the operation is an
* entire new modified array value.
*
- * refattrlength - typlen of array type
- * refelemtype - type of the result of the ArrayRef operation
- * refelemlength - typlen of the array element type
- * refelembyval - is the element type pass-by-value?
- * refupperindexpr - expressions that evaluate to upper array indexes
- * reflowerindexpr - expressions that evaluate to lower array indexes
- * refexpr - the expression that evaluates to an array value
- * refassgnexpr - expression for the source value, or NULL if fetch
- *
* If reflowerindexpr = NIL, then we are fetching or storing a single array
* element at the subscripts given by refupperindexpr. Otherwise we are
* fetching or storing an array slice, that is a rectangular subarray
@@ -432,22 +383,23 @@ typedef struct SubLink
typedef struct ArrayRef
{
NodeTag type;
- int refattrlength;
- int refelemlength;
- Oid refelemtype;
- bool refelembyval;
- List *refupperindexpr;
- List *reflowerindexpr;
- Node *refexpr;
- Node *refassgnexpr;
+ int refattrlength; /* typlen of array type */
+ int refelemlength; /* typlen of the array element type */
+ Oid refelemtype; /* type of the result of the ArrayRef
+ * operation */
+ bool refelembyval; /* is the element type pass-by-value? */
+ List *refupperindexpr; /* expressions that evaluate to upper
+ * array indexes */
+ List *reflowerindexpr; /* expressions that evaluate to lower
+ * array indexes */
+ Node *refexpr; /* the expression that evaluates to an
+ * array value */
+ Node *refassgnexpr; /* expression for the source value, or NULL
+ * if fetch */
} ArrayRef;
/* ----------------
* FieldSelect
- * arg - input expression
- * fieldnum - attribute number of field to extract
- * resulttype - type of the field (result type of this node)
- * resulttypmod - output typmod (usually -1)
*
* FieldSelect represents the operation of extracting one field from a tuple
* value. At runtime, the input expression is expected to yield a Datum
@@ -459,17 +411,15 @@ typedef struct ArrayRef
typedef struct FieldSelect
{
NodeTag type;
- Node *arg;
- AttrNumber fieldnum;
- Oid resulttype;
- int32 resulttypmod;
+ Node *arg; /* input expression */
+ AttrNumber fieldnum; /* attribute number of field to extract */
+ Oid resulttype; /* type of the field (result type of this
+ * node) */
+ int32 resulttypmod; /* output typmod (usually -1) */
} FieldSelect;
/* ----------------
* RelabelType
- * arg - input expression
- * resulttype - output type of coercion expression
- * resulttypmod - output typmod (usually -1)
*
* RelabelType represents a "dummy" type coercion between two binary-
* compatible datatypes, such as reinterpreting the result of an OID
@@ -484,9 +434,9 @@ typedef struct FieldSelect
typedef struct RelabelType
{
NodeTag type;
- Node *arg;
- Oid resulttype;
- int32 resulttypmod;
+ Node *arg; /* input expression */
+ Oid resulttype; /* output type of coercion expression */
+ int32 resulttypmod; /* output typmod (usually -1) */
} RelabelType;
--
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