diff options
Diffstat (limited to 'src/backend/executor/execMain.c')
| -rw-r--r-- | src/backend/executor/execMain.c | 144 |
1 files changed, 131 insertions, 13 deletions
diff --git a/src/backend/executor/execMain.c b/src/backend/executor/execMain.c index 5ce90902b4c..e11869ce783 100644 --- a/src/backend/executor/execMain.c +++ b/src/backend/executor/execMain.c @@ -26,7 +26,7 @@ * * * IDENTIFICATION - * $Header: /cvsroot/pgsql/src/backend/executor/execMain.c,v 1.75 1999/02/07 16:17:11 wieck Exp $ + * $Header: /cvsroot/pgsql/src/backend/executor/execMain.c,v 1.76 1999/02/08 14:14:09 wieck Exp $ * *------------------------------------------------------------------------- */ @@ -60,21 +60,27 @@ void ExecCheckPerms(CmdType operation, int resultRelation, List *rangeTable, /* decls for local routines only used within this module */ -static TupleDesc InitPlan(CmdType operation, Query *parseTree, - Plan *plan, EState *estate); -static void EndPlan(Plan *plan, EState *estate); +static TupleDesc InitPlan(CmdType operation, + Query *parseTree, + Plan *plan, + EState *estate); +static void EndPlan(Plan *plan, + EState *estate); static TupleTableSlot *ExecutePlan(EState *estate, Plan *plan, - CmdType operation, int numberTuples, ScanDirection direction, - DestReceiver *destfunc); + CmdType operation, + int offsetTuples, + int numberTuples, + ScanDirection direction, + DestReceiver *destfunc); static void ExecRetrieve(TupleTableSlot *slot, - DestReceiver *destfunc, - EState *estate); + DestReceiver *destfunc, + EState *estate); static void ExecAppend(TupleTableSlot *slot, ItemPointer tupleid, - EState *estate); + EState *estate); static void ExecDelete(TupleTableSlot *slot, ItemPointer tupleid, - EState *estate); + EState *estate); static void ExecReplace(TupleTableSlot *slot, ItemPointer tupleid, - EState *estate); + EState *estate); TupleTableSlot *EvalPlanQual(EState *estate, Index rti, ItemPointer tid); static TupleTableSlot *EvalPlanQualNext(EState *estate); @@ -187,13 +193,16 @@ ExecutorStart(QueryDesc *queryDesc, EState *estate) * ---------------------------------------------------------------- */ TupleTableSlot * -ExecutorRun(QueryDesc *queryDesc, EState *estate, int feature, int count) +ExecutorRun(QueryDesc *queryDesc, EState *estate, int feature, + Node *limoffset, Node *limcount) { CmdType operation; Plan *plan; TupleTableSlot *result; CommandDest dest; DestReceiver *destfunc; + int offset = 0; + int count = 0; /****************** * sanity checks @@ -222,6 +231,96 @@ ExecutorRun(QueryDesc *queryDesc, EState *estate, int feature, int count) */ (*destfunc->setup) (destfunc, (TupleDesc) NULL); + /****************** + * if given get the offset of the LIMIT clause + ****************** + */ + if (limoffset != NULL) + { + Const *coffset; + Param *poffset; + ParamListInfo paramLI; + int i; + + switch (nodeTag(limoffset)) + { + case T_Const: + coffset = (Const *)limoffset; + offset = (int)(coffset->constvalue); + break; + + case T_Param: + poffset = (Param *)limoffset; + paramLI = estate->es_param_list_info; + + if (paramLI == NULL) + elog(ERROR, "parameter for limit offset not in executor state"); + for (i = 0; paramLI[i].kind != PARAM_INVALID; i++) + { + if (paramLI[i].kind == PARAM_NUM && paramLI[i].id == poffset->paramid) + break; + } + if (paramLI[i].kind == PARAM_INVALID) + elog(ERROR, "parameter for limit offset not in executor state"); + if (paramLI[i].isnull) + elog(ERROR, "limit offset cannot be NULL value"); + offset = (int)(paramLI[i].value); + + break; + + default: + elog(ERROR, "unexpected node type %d as limit offset", nodeTag(limoffset)); + } + + if (offset < 0) + elog(ERROR, "limit offset cannot be negative"); + } + + /****************** + * if given get the count of the LIMIT clause + ****************** + */ + if (limcount != NULL) + { + Const *ccount; + Param *pcount; + ParamListInfo paramLI; + int i; + + switch (nodeTag(limcount)) + { + case T_Const: + ccount = (Const *)limcount; + count = (int)(ccount->constvalue); + break; + + case T_Param: + pcount = (Param *)limcount; + paramLI = estate->es_param_list_info; + + if (paramLI == NULL) + elog(ERROR, "parameter for limit count not in executor state"); + for (i = 0; paramLI[i].kind != PARAM_INVALID; i++) + { + if (paramLI[i].kind == PARAM_NUM && paramLI[i].id == pcount->paramid) + break; + } + if (paramLI[i].kind == PARAM_INVALID) + elog(ERROR, "parameter for limit count not in executor state"); + if (paramLI[i].isnull) + elog(ERROR, "limit count cannot be NULL value"); + count = (int)(paramLI[i].value); + + break; + + default: + elog(ERROR, "unexpected node type %d as limit count", nodeTag(limcount)); + } + + if (count < 0) + elog(ERROR, "limit count cannot be negative"); + } + switch (feature) { @@ -229,7 +328,8 @@ ExecutorRun(QueryDesc *queryDesc, EState *estate, int feature, int count) result = ExecutePlan(estate, plan, operation, - ALL_TUPLES, + offset, + count, ForwardScanDirection, destfunc); break; @@ -237,6 +337,7 @@ ExecutorRun(QueryDesc *queryDesc, EState *estate, int feature, int count) result = ExecutePlan(estate, plan, operation, + offset, count, ForwardScanDirection, destfunc); @@ -250,6 +351,7 @@ ExecutorRun(QueryDesc *queryDesc, EState *estate, int feature, int count) result = ExecutePlan(estate, plan, operation, + offset, count, BackwardScanDirection, destfunc); @@ -264,6 +366,7 @@ ExecutorRun(QueryDesc *queryDesc, EState *estate, int feature, int count) result = ExecutePlan(estate, plan, operation, + 0, ONE_TUPLE, ForwardScanDirection, destfunc); @@ -784,6 +887,7 @@ static TupleTableSlot * ExecutePlan(EState *estate, Plan *plan, CmdType operation, + int offsetTuples, int numberTuples, ScanDirection direction, DestReceiver* destfunc) @@ -846,6 +950,20 @@ lnext:; } /****************** + * For now we completely execute the plan and skip + * result tuples if requested by LIMIT offset. + * Finally we should try to do it in deeper levels + * if possible (during index scan) + * - Jan + ****************** + */ + if (offsetTuples > 0) + { + --offsetTuples; + continue; + } + + /****************** * if we have a junk filter, then project a new * tuple with the junk removed. * |