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| author | Tom Lane <tgl@sss.pgh.pa.us> | 2010-01-01 21:53:49 +0000 |
|---|---|---|
| committer | Tom Lane <tgl@sss.pgh.pa.us> | 2010-01-01 21:53:49 +0000 |
| commit | 29c4ad98293e3c5cb3fcdd413a3f4904efff8762 (patch) | |
| tree | 4e4eeea2655e87eca4d3d0dd97f3e2b7d5f1e032 /src/backend/executor/nodeIndexscan.c | |
| parent | 15faca259651c065bb20e746777f5fb9eb9d50a1 (diff) | |
| download | postgresql-29c4ad98293e3c5cb3fcdd413a3f4904efff8762.tar.gz postgresql-29c4ad98293e3c5cb3fcdd413a3f4904efff8762.zip | |
Support "x IS NOT NULL" clauses as indexscan conditions. This turns out
to be just a minor extension of the previous patch that made "x IS NULL"
indexable, because we can treat the IS NOT NULL condition as if it were
"x < NULL" or "x > NULL" (depending on the index's NULLS FIRST/LAST option),
just like IS NULL is treated like "x = NULL". Aside from any possible
usefulness in its own right, this is an important improvement for
index-optimized MAX/MIN aggregates: it is now reliably possible to get
a column's min or max value cheaply, even when there are a lot of nulls
cluttering the interesting end of the index.
Diffstat (limited to 'src/backend/executor/nodeIndexscan.c')
| -rw-r--r-- | src/backend/executor/nodeIndexscan.c | 29 |
1 files changed, 23 insertions, 6 deletions
diff --git a/src/backend/executor/nodeIndexscan.c b/src/backend/executor/nodeIndexscan.c index b136825dc8f..df877ae191e 100644 --- a/src/backend/executor/nodeIndexscan.c +++ b/src/backend/executor/nodeIndexscan.c @@ -8,7 +8,7 @@ * * * IDENTIFICATION - * $PostgreSQL: pgsql/src/backend/executor/nodeIndexscan.c,v 1.136 2009/10/26 02:26:31 tgl Exp $ + * $PostgreSQL: pgsql/src/backend/executor/nodeIndexscan.c,v 1.137 2010/01/01 21:53:49 tgl Exp $ * *------------------------------------------------------------------------- */ @@ -640,7 +640,8 @@ ExecInitIndexScan(IndexScan *node, EState *estate, int eflags) * (Note that we treat all array-expressions as requiring runtime evaluation, * even if they happen to be constants.) * - * 5. NullTest ("indexkey IS NULL"). We just fill in the ScanKey properly. + * 5. NullTest ("indexkey IS NULL/IS NOT NULL"). We just fill in the + * ScanKey properly. * * Input params are: * @@ -987,13 +988,14 @@ ExecIndexBuildScanKeys(PlanState *planstate, Relation index, Index scanrelid, } else if (IsA(clause, NullTest)) { - /* indexkey IS NULL */ - Assert(((NullTest *) clause)->nulltesttype == IS_NULL); + /* indexkey IS NULL or indexkey IS NOT NULL */ + NullTest *ntest = (NullTest *) clause; + int flags; /* * argument should be the index key Var, possibly relabeled */ - leftop = ((NullTest *) clause)->arg; + leftop = ntest->arg; if (leftop && IsA(leftop, RelabelType)) leftop = ((RelabelType *) leftop)->arg; @@ -1009,8 +1011,23 @@ ExecIndexBuildScanKeys(PlanState *planstate, Relation index, Index scanrelid, /* * initialize the scan key's fields appropriately */ + switch (ntest->nulltesttype) + { + case IS_NULL: + flags = SK_ISNULL | SK_SEARCHNULL; + break; + case IS_NOT_NULL: + flags = SK_ISNULL | SK_SEARCHNOTNULL; + break; + default: + elog(ERROR, "unrecognized nulltesttype: %d", + (int) ntest->nulltesttype); + flags = 0; /* keep compiler quiet */ + break; + } + ScanKeyEntryInitialize(this_scan_key, - SK_ISNULL | SK_SEARCHNULL, + flags, varattno, /* attribute number to scan */ InvalidStrategy, /* no strategy */ InvalidOid, /* no strategy subtype */ |