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Divide functions into three volatility classes (immutable, stable, and

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volatile), rather than the old cachable/noncachable distinction.  This
allows indexscan optimizations in many places where we formerly didn't.
Also, add a pronamespace column to pg_proc (it doesn't do anything yet,
however).
This commit is contained in:
Tom Lane
2002-04-05 00:31:36 +00:00
parent 0e11aea246
commit 4bdb4be62e
26 changed files with 1668 additions and 1542 deletions
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38
src/backend/commands/define.c
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@@ -10,7 +10,7 @@
*
*
* IDENTIFICATION
* $Header: /cvsroot/pgsql/src/backend/commands/define.c,v 1.72 2002/03/29 19:06:06 tgl Exp $
* $Header: /cvsroot/pgsql/src/backend/commands/define.c,v 1.73 2002/04/05 00:31:25 tgl Exp $
*
* DESCRIPTION
* The "DefineFoo" routines take the parse tree and pick out the
@@ -145,7 +145,7 @@ static void
compute_full_attributes(List *parameters,
int32 *byte_pct_p, int32 *perbyte_cpu_p,
int32 *percall_cpu_p, int32 *outin_ratio_p,
bool *canCache_p, bool *isStrict_p)
bool *isStrict_p, char *volatility_p)
{
/*-------------
* Interpret the parameters *parameters and return their contents as
@@ -156,18 +156,15 @@ compute_full_attributes(List *parameters,
*
* Note: currently, only two of these parameters actually do anything:
*
* * canCache means the optimizer's constant-folder is allowed to
* pre-evaluate the function when all its inputs are constants.
*
* * isStrict means the function should not be called when any NULL
* inputs are present; instead a NULL result value should be assumed.
*
* * volatility tells the optimizer whether the function's result can
* be assumed to be repeatable over multiple evaluations.
*
* The other four parameters are not used anywhere. They used to be
* used in the "expensive functions" optimizer, but that's been dead code
* for a long time.
*
* Since canCache and isStrict are useful for any function, we now allow
* attributes to be supplied for all functions regardless of language.
*------------
*/
List *pl;
@@ -177,17 +174,26 @@ compute_full_attributes(List *parameters,
*perbyte_cpu_p = PERBYTE_CPU;
*percall_cpu_p = PERCALL_CPU;
*outin_ratio_p = OUTIN_RATIO;
*canCache_p = false;
*isStrict_p = false;
*volatility_p = PROVOLATILE_VOLATILE;
foreach(pl, parameters)
{
DefElem *param = (DefElem *) lfirst(pl);
if (strcasecmp(param->defname, "iscachable") == 0)
*canCache_p = true;
else if (strcasecmp(param->defname, "isstrict") == 0)
if (strcasecmp(param->defname, "isstrict") == 0)
*isStrict_p = true;
else if (strcasecmp(param->defname, "isimmutable") == 0)
*volatility_p = PROVOLATILE_IMMUTABLE;
else if (strcasecmp(param->defname, "isstable") == 0)
*volatility_p = PROVOLATILE_STABLE;
else if (strcasecmp(param->defname, "isvolatile") == 0)
*volatility_p = PROVOLATILE_VOLATILE;
else if (strcasecmp(param->defname, "iscachable") == 0)
{
/* obsolete spelling of isImmutable */
*volatility_p = PROVOLATILE_IMMUTABLE;
}
else if (strcasecmp(param->defname, "trusted") == 0)
{
/*
@@ -273,8 +279,8 @@ CreateFunction(ProcedureStmt *stmt)
perbyte_cpu,
percall_cpu,
outin_ratio;
bool canCache,
isStrict;
bool isStrict;
char volatility;
HeapTuple languageTuple;
Form_pg_language languageStruct;
@@ -311,7 +317,7 @@ CreateFunction(ProcedureStmt *stmt)
compute_full_attributes(stmt->withClause,
&byte_pct, &perbyte_cpu, &percall_cpu,
&outin_ratio, &canCache, &isStrict);
&outin_ratio, &isStrict, &volatility);
interpret_AS_clause(languageOid, languageName, stmt->as,
&prosrc_str, &probin_str);
@@ -329,8 +335,8 @@ CreateFunction(ProcedureStmt *stmt)
prosrc_str, /* converted to text later */
probin_str, /* converted to text later */
true, /* (obsolete "trusted") */
canCache,
isStrict,
volatility,
byte_pct,
perbyte_cpu,
percall_cpu,