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| author | Tom Lane <tgl@sss.pgh.pa.us> | 2004-03-17 20:48:43 +0000 |
|---|---|---|
| committer | Tom Lane <tgl@sss.pgh.pa.us> | 2004-03-17 20:48:43 +0000 |
| commit | 55f7c3300d164d370d28b127210223d078da524d (patch) | |
| tree | e5c91b7d50eef3b40dd395e3ecce877bb6663636 /src/backend/nodes/readfuncs.c | |
| parent | 8c702ea7ace30026dfff4f2e514027cd4d6d7579 (diff) | |
| download | postgresql-55f7c3300d164d370d28b127210223d078da524d.tar.gz postgresql-55f7c3300d164d370d28b127210223d078da524d.zip | |
Reimplement CASE val WHEN compval1 THEN ... WHEN compval2 THEN ... END
so that the 'val' is computed only once, per recent discussion. The
speedup is not much when 'val' is just a simple variable, but could be
significant for larger expressions. More importantly this avoids issues
with multiple evaluations of a volatile 'val', and it allows the CASE
expression to be reverse-listed in its original form by ruleutils.c.
Diffstat (limited to 'src/backend/nodes/readfuncs.c')
| -rw-r--r-- | src/backend/nodes/readfuncs.c | 18 |
1 files changed, 17 insertions, 1 deletions
diff --git a/src/backend/nodes/readfuncs.c b/src/backend/nodes/readfuncs.c index 93c71fd2247..116345686bf 100644 --- a/src/backend/nodes/readfuncs.c +++ b/src/backend/nodes/readfuncs.c @@ -8,7 +8,7 @@ * * * IDENTIFICATION - * $PostgreSQL: pgsql/src/backend/nodes/readfuncs.c,v 1.165 2004/01/14 23:01:55 tgl Exp $ + * $PostgreSQL: pgsql/src/backend/nodes/readfuncs.c,v 1.166 2004/03/17 20:48:42 tgl Exp $ * * NOTES * Path and Plan nodes do not have any readfuncs support, because we @@ -649,6 +649,20 @@ _readCaseWhen(void) } /* + * _readCaseTestExpr + */ +static CaseTestExpr * +_readCaseTestExpr(void) +{ + READ_LOCALS(CaseTestExpr); + + READ_OID_FIELD(typeId); + READ_INT_FIELD(typeMod); + + READ_DONE(); +} + +/* * _readArrayExpr */ static ArrayExpr * @@ -1010,6 +1024,8 @@ parseNodeString(void) return_value = _readCaseExpr(); else if (MATCH("WHEN", 4)) return_value = _readCaseWhen(); + else if (MATCH("CASETESTEXPR", 12)) + return_value = _readCaseTestExpr(); else if (MATCH("ARRAY", 5)) return_value = _readArrayExpr(); else if (MATCH("COALESCE", 8)) |