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Adjust creation/destruction of TupleDesc data structure to reduce the

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number of palloc calls.  This has a salutory impact on plpgsql operations
with record variables (which create and destroy tupdescs constantly)
and probably helps a bit in some other cases too.
This commit is contained in:
Tom Lane
2005-03-07 04:42:17 +00:00
parent e3d7de6b99
commit a52b4fb131
4 changed files with 82 additions and 104 deletions
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20
src/include/access/tupdesc.h
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@@ -7,7 +7,7 @@
* Portions Copyright (c) 1996-2005, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
* $PostgreSQL: pgsql/src/include/access/tupdesc.h,v 1.46 2004/12/31 22:03:21 pgsql Exp $
* $PostgreSQL: pgsql/src/include/access/tupdesc.h,v 1.47 2005/03/07 04:42:17 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@@ -42,13 +42,17 @@ typedef struct tupleConstr
} TupleConstr;
/*
* This structure contains all information (i.e. from Classes
* pg_attribute, pg_attrdef, pg_constraint) for the structure of a tuple.
* This struct is passed around within the backend to describe the structure
* of tuples. For tuples coming from on-disk relations, the information is
* collected from the pg_attribute, pg_attrdef, and pg_constraint catalogs.
* Transient row types (such as the result of a join query) have anonymous
* TupleDesc structs that generally omit any constraint info; therefore the
* structure is designed to let the constraints be omitted efficiently.
*
* Note that only user attributes, not system attributes, are mentioned in
* TupleDesc; with the exception that tdhasoid indicates if OID is present.
*
* If the tuple is known to correspond to a named rowtype (such as a table's
* If the tupdesc is known to correspond to a named rowtype (such as a table's
* rowtype) then tdtypeid identifies that type and tdtypmod is -1. Otherwise
* tdtypeid is RECORDOID, and tdtypmod can be either -1 for a fully anonymous
* row type, or a value >= 0 to allow the rowtype to be looked up in the
@@ -56,13 +60,13 @@ typedef struct tupleConstr
*/
typedef struct tupleDesc
{
int natts; /* Number of attributes in the tuple */
int natts; /* number of attributes in the tuple */
Form_pg_attribute *attrs;
/* attrs[N] is a pointer to the description of Attribute Number N+1. */
TupleConstr *constr;
/* attrs[N] is a pointer to the description of Attribute Number N+1 */
TupleConstr *constr; /* constraints, or NULL if none */
Oid tdtypeid; /* composite type ID for tuple type */
int32 tdtypmod; /* typmod for tuple type */
bool tdhasoid; /* Tuple has oid attribute in its header */
bool tdhasoid; /* tuple has oid attribute in its header */
} *TupleDesc;