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| author | Simon Riggs <simon@2ndQuadrant.com> | 2015-05-15 14:37:10 -0400 |
|---|---|---|
| committer | Simon Riggs <simon@2ndQuadrant.com> | 2015-05-15 14:37:10 -0400 |
| commit | f6d208d6e51810c73f0e02c477984a6b44627f11 (patch) | |
| tree | 99d540d0b7bda73ff60479f15444f554403d4679 /src/backend/nodes/outfuncs.c | |
| parent | 11a83bbedd73800db70f6f2af5a8eb10d15d39d7 (diff) | |
| download | postgresql-f6d208d6e51810c73f0e02c477984a6b44627f11.tar.gz postgresql-f6d208d6e51810c73f0e02c477984a6b44627f11.zip | |
TABLESAMPLE, SQL Standard and extensible
Add a TABLESAMPLE clause to SELECT statements that allows
user to specify random BERNOULLI sampling or block level
SYSTEM sampling. Implementation allows for extensible
sampling functions to be written, using a standard API.
Basic version follows SQLStandard exactly. Usable
concrete use cases for the sampling API follow in later
commits.
Petr Jelinek
Reviewed by Michael Paquier and Simon Riggs
Diffstat (limited to 'src/backend/nodes/outfuncs.c')
| -rw-r--r-- | src/backend/nodes/outfuncs.c | 48 |
1 files changed, 48 insertions, 0 deletions
diff --git a/src/backend/nodes/outfuncs.c b/src/backend/nodes/outfuncs.c index fe868b889d9..7918553da0a 100644 --- a/src/backend/nodes/outfuncs.c +++ b/src/backend/nodes/outfuncs.c @@ -592,6 +592,14 @@ _outCustomScan(StringInfo str, const CustomScan *node) } static void +_outSampleScan(StringInfo str, const SampleScan *node) +{ + WRITE_NODE_TYPE("SAMPLESCAN"); + + _outScanInfo(str, (const Scan *) node); +} + +static void _outJoin(StringInfo str, const Join *node) { WRITE_NODE_TYPE("JOIN"); @@ -2445,6 +2453,36 @@ _outCommonTableExpr(StringInfo str, const CommonTableExpr *node) } static void +_outRangeTableSample(StringInfo str, const RangeTableSample *node) +{ + WRITE_NODE_TYPE("RANGETABLESAMPLE"); + + WRITE_NODE_FIELD(relation); + WRITE_STRING_FIELD(method); + WRITE_NODE_FIELD(repeatable); + WRITE_NODE_FIELD(args); +} + +static void +_outTableSampleClause(StringInfo str, const TableSampleClause *node) +{ + WRITE_NODE_TYPE("TABLESAMPLECLAUSE"); + + WRITE_OID_FIELD(tsmid); + WRITE_BOOL_FIELD(tsmseqscan); + WRITE_BOOL_FIELD(tsmpagemode); + WRITE_OID_FIELD(tsminit); + WRITE_OID_FIELD(tsmnextblock); + WRITE_OID_FIELD(tsmnexttuple); + WRITE_OID_FIELD(tsmexaminetuple); + WRITE_OID_FIELD(tsmend); + WRITE_OID_FIELD(tsmreset); + WRITE_OID_FIELD(tsmcost); + WRITE_NODE_FIELD(repeatable); + WRITE_NODE_FIELD(args); +} + +static void _outSetOperationStmt(StringInfo str, const SetOperationStmt *node) { WRITE_NODE_TYPE("SETOPERATIONSTMT"); @@ -2474,6 +2512,7 @@ _outRangeTblEntry(StringInfo str, const RangeTblEntry *node) case RTE_RELATION: WRITE_OID_FIELD(relid); WRITE_CHAR_FIELD(relkind); + WRITE_NODE_FIELD(tablesample); break; case RTE_SUBQUERY: WRITE_NODE_FIELD(subquery); @@ -2973,6 +3012,9 @@ _outNode(StringInfo str, const void *obj) case T_CustomScan: _outCustomScan(str, obj); break; + case T_SampleScan: + _outSampleScan(str, obj); + break; case T_Join: _outJoin(str, obj); break; @@ -3319,6 +3361,12 @@ _outNode(StringInfo str, const void *obj) case T_CommonTableExpr: _outCommonTableExpr(str, obj); break; + case T_RangeTableSample: + _outRangeTableSample(str, obj); + break; + case T_TableSampleClause: + _outTableSampleClause(str, obj); + break; case T_SetOperationStmt: _outSetOperationStmt(str, obj); break; |