1 /*-------------------------------------------------------------------------
4 * routines to handle BitmapAnd nodes.
6 * Portions Copyright (c) 1996-2019, PostgreSQL Global Development Group
7 * Portions Copyright (c) 1994, Regents of the University of California
11 * src/backend/executor/nodeBitmapAnd.c
13 *-------------------------------------------------------------------------
16 * ExecInitBitmapAnd - initialize the BitmapAnd node
17 * MultiExecBitmapAnd - retrieve the result bitmap from the node
18 * ExecEndBitmapAnd - shut down the BitmapAnd node
19 * ExecReScanBitmapAnd - rescan the BitmapAnd node
22 * BitmapAnd nodes don't make use of their left and right
23 * subtrees, rather they maintain a list of subplans,
24 * much like Append nodes. The logic is much simpler than
25 * Append, however, since we needn't cope with forward/backward
31 #include "executor/execdebug.h"
32 #include "executor/nodeBitmapAnd.h"
35 /* ----------------------------------------------------------------
38 * stub for pro forma compliance
39 * ----------------------------------------------------------------
41 static TupleTableSlot *
42 ExecBitmapAnd(PlanState *pstate)
44 elog(ERROR, "BitmapAnd node does not support ExecProcNode call convention");
48 /* ----------------------------------------------------------------
51 * Begin all of the subscans of the BitmapAnd node.
52 * ----------------------------------------------------------------
55 ExecInitBitmapAnd(BitmapAnd *node, EState *estate, int eflags)
57 BitmapAndState *bitmapandstate = makeNode(BitmapAndState);
58 PlanState **bitmapplanstates;
64 /* check for unsupported flags */
65 Assert(!(eflags & (EXEC_FLAG_BACKWARD | EXEC_FLAG_MARK)));
68 * Set up empty vector of subplan states
70 nplans = list_length(node->bitmapplans);
72 bitmapplanstates = (PlanState **) palloc0(nplans * sizeof(PlanState *));
75 * create new BitmapAndState for our BitmapAnd node
77 bitmapandstate->ps.plan = (Plan *) node;
78 bitmapandstate->ps.state = estate;
79 bitmapandstate->ps.ExecProcNode = ExecBitmapAnd;
80 bitmapandstate->bitmapplans = bitmapplanstates;
81 bitmapandstate->nplans = nplans;
84 * call ExecInitNode on each of the plans to be executed and save the
85 * results into the array "bitmapplanstates".
88 foreach(l, node->bitmapplans)
90 initNode = (Plan *) lfirst(l);
91 bitmapplanstates[i] = ExecInitNode(initNode, estate, eflags);
96 * Miscellaneous initialization
98 * BitmapAnd plans don't have expression contexts because they never call
99 * ExecQual or ExecProject. They don't need any tuple slots either.
102 return bitmapandstate;
105 /* ----------------------------------------------------------------
107 * ----------------------------------------------------------------
110 MultiExecBitmapAnd(BitmapAndState *node)
112 PlanState **bitmapplans;
115 TIDBitmap *result = NULL;
117 /* must provide our own instrumentation support */
118 if (node->ps.instrument)
119 InstrStartNode(node->ps.instrument);
122 * get information from the node
124 bitmapplans = node->bitmapplans;
125 nplans = node->nplans;
128 * Scan all the subplans and AND their result bitmaps
130 for (i = 0; i < nplans; i++)
132 PlanState *subnode = bitmapplans[i];
133 TIDBitmap *subresult;
135 subresult = (TIDBitmap *) MultiExecProcNode(subnode);
137 if (!subresult || !IsA(subresult, TIDBitmap))
138 elog(ERROR, "unrecognized result from subplan");
141 result = subresult; /* first subplan */
144 tbm_intersect(result, subresult);
149 * If at any stage we have a completely empty bitmap, we can fall out
150 * without evaluating the remaining subplans, since ANDing them can no
151 * longer change the result. (Note: the fact that indxpath.c orders
152 * the subplans by selectivity should make this case more likely to
155 if (tbm_is_empty(result))
160 elog(ERROR, "BitmapAnd doesn't support zero inputs");
162 /* must provide our own instrumentation support */
163 if (node->ps.instrument)
164 InstrStopNode(node->ps.instrument, 0 /* XXX */ );
166 return (Node *) result;
169 /* ----------------------------------------------------------------
172 * Shuts down the subscans of the BitmapAnd node.
174 * Returns nothing of interest.
175 * ----------------------------------------------------------------
178 ExecEndBitmapAnd(BitmapAndState *node)
180 PlanState **bitmapplans;
185 * get information from the node
187 bitmapplans = node->bitmapplans;
188 nplans = node->nplans;
191 * shut down each of the subscans (that we've initialized)
193 for (i = 0; i < nplans; i++)
196 ExecEndNode(bitmapplans[i]);
201 ExecReScanBitmapAnd(BitmapAndState *node)
205 for (i = 0; i < node->nplans; i++)
207 PlanState *subnode = node->bitmapplans[i];
210 * ExecReScan doesn't know about my subplans, so I have to do
211 * changed-parameter signaling myself.
213 if (node->ps.chgParam != NULL)
214 UpdateChangedParamSet(subnode, node->ps.chgParam);
217 * If chgParam of subnode is not null then plan will be re-scanned by
218 * first ExecProcNode.
220 if (subnode->chgParam == NULL)