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Move structure comments from the top block down to the line entries for

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this file to match all the other files, and to be clearer.
This commit is contained in:
Bruce Momjian
2001-01-17 06:41:31 +00:00
parent 4c4f305b15
commit 26e0321191
2 changed files with 121 additions and 171 deletions
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2
src/backend/optimizer/README
View File

@@ -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.

288
src/include/nodes/primnodes.h
View File

@@ -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;
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;