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Diffstat (limited to 'src/backend/executor/nodeUnique.c')
| -rw-r--r-- | src/backend/executor/nodeUnique.c | 237 |
1 files changed, 0 insertions, 237 deletions
diff --git a/src/backend/executor/nodeUnique.c b/src/backend/executor/nodeUnique.c deleted file mode 100644 index b71403de0b8..00000000000 --- a/src/backend/executor/nodeUnique.c +++ /dev/null @@ -1,237 +0,0 @@ -/*------------------------------------------------------------------------- - * - * nodeUnique.c - * Routines to handle unique'ing of queries where appropriate - * - * Portions Copyright (c) 1996-2002, PostgreSQL Global Development Group - * Portions Copyright (c) 1994, Regents of the University of California - * - * - * IDENTIFICATION - * $Header: /cvsroot/pgsql/src/backend/executor/nodeUnique.c,v 1.34 2002/06/20 20:29:28 momjian Exp $ - * - *------------------------------------------------------------------------- - */ -/* - * INTERFACE ROUTINES - * ExecUnique - generate a unique'd temporary relation - * ExecInitUnique - initialize node and subnodes.. - * ExecEndUnique - shutdown node and subnodes - * - * NOTES - * Assumes tuples returned from subplan arrive in - * sorted order. - * - */ - -#include "postgres.h" - -#include "access/heapam.h" -#include "executor/executor.h" -#include "executor/nodeGroup.h" -#include "executor/nodeUnique.h" - -/* ---------------------------------------------------------------- - * ExecUnique - * - * This is a very simple node which filters out duplicate - * tuples from a stream of sorted tuples from a subplan. - * ---------------------------------------------------------------- - */ -TupleTableSlot * /* return: a tuple or NULL */ -ExecUnique(Unique *node) -{ - UniqueState *uniquestate; - TupleTableSlot *resultTupleSlot; - TupleTableSlot *slot; - Plan *outerPlan; - TupleDesc tupDesc; - - /* - * get information from the node - */ - uniquestate = node->uniquestate; - outerPlan = outerPlan((Plan *) node); - resultTupleSlot = uniquestate->cstate.cs_ResultTupleSlot; - tupDesc = ExecGetResultType(&uniquestate->cstate); - - /* - * now loop, returning only non-duplicate tuples. We assume that the - * tuples arrive in sorted order so we can detect duplicates easily. - */ - for (;;) - { - /* - * fetch a tuple from the outer subplan - */ - slot = ExecProcNode(outerPlan, (Plan *) node); - if (TupIsNull(slot)) - return NULL; - - /* - * Always return the first tuple from the subplan. - */ - if (uniquestate->priorTuple == NULL) - break; - - /* - * Else test if the new tuple and the previously returned tuple - * match. If so then we loop back and fetch another new tuple - * from the subplan. - */ - if (!execTuplesMatch(slot->val, uniquestate->priorTuple, - tupDesc, - node->numCols, node->uniqColIdx, - uniquestate->eqfunctions, - uniquestate->tempContext)) - break; - } - - /* - * We have a new tuple different from the previous saved tuple (if - * any). Save it and return it. We must copy it because the source - * subplan won't guarantee that this source tuple is still accessible - * after fetching the next source tuple. - * - * Note that we manage the copy ourselves. We can't rely on the result - * tuple slot to maintain the tuple reference because our caller may - * replace the slot contents with a different tuple (see junk filter - * handling in execMain.c). We assume that the caller will no longer - * be interested in the current tuple after he next calls us. - */ - if (uniquestate->priorTuple != NULL) - heap_freetuple(uniquestate->priorTuple); - uniquestate->priorTuple = heap_copytuple(slot->val); - - ExecStoreTuple(uniquestate->priorTuple, - resultTupleSlot, - InvalidBuffer, - false); /* tuple does not belong to slot */ - - return resultTupleSlot; -} - -/* ---------------------------------------------------------------- - * ExecInitUnique - * - * This initializes the unique node state structures and - * the node's subplan. - * ---------------------------------------------------------------- - */ -bool /* return: initialization status */ -ExecInitUnique(Unique *node, EState *estate, Plan *parent) -{ - UniqueState *uniquestate; - Plan *outerPlan; - - /* - * assign execution state to node - */ - node->plan.state = estate; - - /* - * create new UniqueState for node - */ - uniquestate = makeNode(UniqueState); - node->uniquestate = uniquestate; - uniquestate->priorTuple = NULL; - - /* - * Miscellaneous initialization - * - * Unique nodes have no ExprContext initialization because they never - * call ExecQual or ExecProject. But they do need a per-tuple memory - * context anyway for calling execTuplesMatch. - */ - uniquestate->tempContext = - AllocSetContextCreate(CurrentMemoryContext, - "Unique", - ALLOCSET_DEFAULT_MINSIZE, - ALLOCSET_DEFAULT_INITSIZE, - ALLOCSET_DEFAULT_MAXSIZE); - -#define UNIQUE_NSLOTS 1 - - /* - * Tuple table initialization - */ - ExecInitResultTupleSlot(estate, &uniquestate->cstate); - - /* - * then initialize outer plan - */ - outerPlan = outerPlan((Plan *) node); - ExecInitNode(outerPlan, estate, (Plan *) node); - - /* - * unique nodes do no projections, so initialize projection info for - * this node appropriately - */ - ExecAssignResultTypeFromOuterPlan((Plan *) node, &uniquestate->cstate); - uniquestate->cstate.cs_ProjInfo = NULL; - - /* - * Precompute fmgr lookup data for inner loop - */ - uniquestate->eqfunctions = - execTuplesMatchPrepare(ExecGetResultType(&uniquestate->cstate), - node->numCols, - node->uniqColIdx); - - return TRUE; -} - -int -ExecCountSlotsUnique(Unique *node) -{ - return ExecCountSlotsNode(outerPlan(node)) + - ExecCountSlotsNode(innerPlan(node)) + - UNIQUE_NSLOTS; -} - -/* ---------------------------------------------------------------- - * ExecEndUnique - * - * This shuts down the subplan and frees resources allocated - * to this node. - * ---------------------------------------------------------------- - */ -void -ExecEndUnique(Unique *node) -{ - UniqueState *uniquestate = node->uniquestate; - - ExecEndNode(outerPlan((Plan *) node), (Plan *) node); - - MemoryContextDelete(uniquestate->tempContext); - - /* clean up tuple table */ - ExecClearTuple(uniquestate->cstate.cs_ResultTupleSlot); - if (uniquestate->priorTuple != NULL) - { - heap_freetuple(uniquestate->priorTuple); - uniquestate->priorTuple = NULL; - } -} - - -void -ExecReScanUnique(Unique *node, ExprContext *exprCtxt, Plan *parent) -{ - UniqueState *uniquestate = node->uniquestate; - - ExecClearTuple(uniquestate->cstate.cs_ResultTupleSlot); - if (uniquestate->priorTuple != NULL) - { - heap_freetuple(uniquestate->priorTuple); - uniquestate->priorTuple = NULL; - } - - /* - * if chgParam of subnode is not null then plan will be re-scanned by - * first ExecProcNode. - */ - if (((Plan *) node)->lefttree->chgParam == NULL) - ExecReScan(((Plan *) node)->lefttree, exprCtxt, (Plan *) node); - -} |