]> granicus.if.org Git - postgresql/commitdiff
Allow GIN's extractQuery method to signal that nothing can satisfy the query.
authorTeodor Sigaev <teodor@sigaev.ru>
Wed, 31 Jan 2007 15:09:45 +0000 (15:09 +0000)
committerTeodor Sigaev <teodor@sigaev.ru>
Wed, 31 Jan 2007 15:09:45 +0000 (15:09 +0000)
In this case extractQuery should returns -1 as nentries. This changes
prototype of extractQuery method to use int32* instead of uint32* for
nentries argument.
Based on that gincostestimate may see two corner cases: nothing will be found
or seqscan should be used.

Per proposal at http://archives.postgresql.org/pgsql-hackers/2007-01/msg01581.php

PS tsearch_core patch should be sightly modified to support changes, but I'm
waiting a verdict about reviewing of tsearch_core patch.

contrib/intarray/_int_gin.c
contrib/tsearch2/ginidx.c
doc/src/sgml/gin.sgml
src/backend/access/gin/ginarrayproc.c
src/backend/access/gin/ginbulk.c
src/backend/access/gin/ginget.c
src/backend/access/gin/gininsert.c
src/backend/access/gin/ginscan.c
src/backend/access/gin/ginutil.c
src/backend/utils/adt/selfuncs.c
src/include/access/gin.h

index 7bb9599b3350b176a3550b9ea3faff7843fb81d2..22484287862d26619d75c1aa3668d8cd98fc6351 100644 (file)
@@ -6,7 +6,7 @@ Datum           ginint4_queryextract(PG_FUNCTION_ARGS);
 Datum
 ginint4_queryextract(PG_FUNCTION_ARGS)
 {
-       uint32     *nentries = (uint32 *) PG_GETARG_POINTER(1);
+       int32      *nentries = (int32 *) PG_GETARG_POINTER(1);
        StrategyNumber strategy = PG_GETARG_UINT16(2);
        Datum      *res = NULL;
 
@@ -57,6 +57,19 @@ ginint4_queryextract(PG_FUNCTION_ARGS)
                }
        }
 
+       if ( nentries == 0 )
+       {
+               switch( strategy )
+               {
+                       case BooleanSearchStrategy:
+                       case RTOverlapStrategyNumber:
+                                       *nentries = -1; /* nobody can be found */
+                                       break;
+                       default:   /* require fullscan: GIN can't find void arrays */
+                       break;
+               }
+       }
+
        PG_RETURN_POINTER(res);
 }
 
index c1bb173e1ce37b03e8d7edd9df06ae1ecb829581..01766923c1ce74ec42538d5af904a14580ac0181 100644 (file)
@@ -21,7 +21,7 @@ Datum
 gin_extract_tsvector(PG_FUNCTION_ARGS)
 {
        tsvector   *vector = (tsvector *) PG_DETOAST_DATUM(PG_GETARG_DATUM(0));
-       uint32     *nentries = (uint32 *) PG_GETARG_POINTER(1);
+       int32      *nentries = (int32 *) PG_GETARG_POINTER(1);
        Datum      *entries = NULL;
 
        *nentries = 0;
@@ -30,7 +30,7 @@ gin_extract_tsvector(PG_FUNCTION_ARGS)
                int                     i;
                WordEntry  *we = ARRPTR(vector);
 
-               *nentries = (uint32) vector->size;
+               *nentries = (int32) vector->size;
                entries = (Datum *) palloc(sizeof(Datum) * vector->size);
 
                for (i = 0; i < vector->size; i++)
@@ -58,7 +58,7 @@ Datum
 gin_extract_tsquery(PG_FUNCTION_ARGS)
 {
        QUERYTYPE  *query = (QUERYTYPE *) PG_DETOAST_DATUM(PG_GETARG_DATUM(0));
-       uint32     *nentries = (uint32 *) PG_GETARG_POINTER(1);
+       int32      *nentries = (int32 *) PG_GETARG_POINTER(1);
        StrategyNumber strategy = DatumGetUInt16(PG_GETARG_DATUM(2));
        Datum      *entries = NULL;
 
@@ -99,6 +99,8 @@ gin_extract_tsquery(PG_FUNCTION_ARGS)
                        }
 
        }
+       else
+               *nentries = -1; /* nothing can be found */
 
        PG_FREE_IF_COPY(query, 0);
        PG_RETURN_POINTER(entries);
index c2bbad42bfaa2ba7960e91643503981b5fbce0c9..32919e58711dd396b4d37cd9173dc0ff06ac8833 100644 (file)
@@ -1,4 +1,4 @@
-<!-- $PostgreSQL: pgsql/doc/src/sgml/gin.sgml,v 2.7 2006/12/01 23:46:46 tgl Exp $ -->
+<!-- $PostgreSQL: pgsql/doc/src/sgml/gin.sgml,v 2.8 2007/01/31 15:09:45 teodor Exp $ -->
 
 <chapter id="GIN">
 <title>GIN Indexes</title>
@@ -77,7 +77,7 @@
     </varlistentry>
 
     <varlistentry>
-     <term>Datum* extractValue(Datum inputValue, uint32 *nkeys)</term>
+     <term>Datum* extractValue(Datum inputValue, int32 *nkeys)</term>
      <listitem>
       <para>
        Returns an array of keys given a value to be indexed.  The
@@ -87,7 +87,7 @@
     </varlistentry>
 
     <varlistentry>
-     <term>Datum* extractQuery(Datum query, uint32 *nkeys,
+     <term>Datum* extractQuery(Datum query, int32 *nkeys,
         StrategyNumber n)</term>
      <listitem>
       <para>
        to consult <literal>n</> to determine the data type of
        <literal>query</> and the key values that need to be extracted.
        The number of returned keys must be stored into <literal>*nkeys</>.
+          If number of keys is equal to zero then <function>extractQuery</> 
+          should store 0 or -1 into <literal>*nkeys</>. 0 means that any 
+          row matches the <literal>query</> and sequence scan should be 
+          produced. -1 means nothing can satisfy <literal>query</>. 
+          Choice of value should be based on semantics meaning of operation with 
+          given strategy number.
       </para>
      </listitem>
     </varlistentry>
index fd505333bc5b8971049b024b605c47812b7aee1e..a46def63c501a7483b11a0a8c357d7f843bb5b43 100644 (file)
@@ -8,7 +8,7 @@
  * Portions Copyright (c) 1994, Regents of the University of California
  *
  * IDENTIFICATION
- *       $PostgreSQL: pgsql/src/backend/access/gin/ginarrayproc.c,v 1.8 2007/01/05 22:19:21 momjian Exp $
+ *       $PostgreSQL: pgsql/src/backend/access/gin/ginarrayproc.c,v 1.9 2007/01/31 15:09:45 teodor Exp $
  *-------------------------------------------------------------------------
  */
 #include "postgres.h"
@@ -38,7 +38,7 @@ Datum
 ginarrayextract(PG_FUNCTION_ARGS)
 {
        ArrayType  *array;
-       uint32     *nentries = (uint32 *) PG_GETARG_POINTER(1);
+       int32      *nentries = (int32 *) PG_GETARG_POINTER(1);
        Datum      *entries = NULL;
        int16           elmlen;
        bool            elmbyval;
@@ -60,6 +60,21 @@ ginarrayextract(PG_FUNCTION_ARGS)
                                          elmlen, elmbyval, elmalign,
                                          &entries, NULL, (int *) nentries);
 
+       if ( *nentries == 0 && PG_NARGS() == 3 )
+       {
+               switch( PG_GETARG_UINT16(2) )
+               {
+                       case GinOverlapStrategy:
+                                       *nentries = -1; /* nobody can be found */
+                                       break;
+                       case GinContainsStrategy:
+                       case GinContainedStrategy:
+                       case GinEqualStrategy:
+                       default:        /* require fullscan: GIN can't find void arrays */
+                               break;
+               }
+       }
+
        /* we should not free array, entries[i] points into it */
        PG_RETURN_POINTER(entries);
 }
index f45d5b63958f013079f20a31e8a9dadf84f6d8ed..d3b6f0bceb1ca3333f87dea95c34de579685e2eb 100644 (file)
@@ -8,7 +8,7 @@
  * Portions Copyright (c) 1994, Regents of the University of California
  *
  * IDENTIFICATION
- *                     $PostgreSQL: pgsql/src/backend/access/gin/ginbulk.c,v 1.7 2007/01/05 22:19:21 momjian Exp $
+ *                     $PostgreSQL: pgsql/src/backend/access/gin/ginbulk.c,v 1.8 2007/01/31 15:09:45 teodor Exp $
  *-------------------------------------------------------------------------
  */
 
@@ -191,13 +191,13 @@ ginChooseElem(BuildAccumulator *accum, ItemPointer heapptr, Datum *entries, uint
  * next middle on left part and middle of right part.
  */
 void
-ginInsertRecordBA(BuildAccumulator *accum, ItemPointer heapptr, Datum *entries, uint32 nentry)
+ginInsertRecordBA(BuildAccumulator *accum, ItemPointer heapptr, Datum *entries, int32 nentry)
 {
        uint32          i,
                                nbit = 0,
                                offset;
 
-       if (nentry == 0)
+       if (nentry <= 0)
                return;
 
        i = nentry - 1;
index 11f034bb213db1141d7031d19e48ed77b8bffb01..2366f3f727e0d41c0727ce48aa0257fc64951868 100644 (file)
@@ -8,7 +8,7 @@
  * Portions Copyright (c) 1994, Regents of the University of California
  *
  * IDENTIFICATION
- *                     $PostgreSQL: pgsql/src/backend/access/gin/ginget.c,v 1.5 2007/01/05 22:19:21 momjian Exp $
+ *                     $PostgreSQL: pgsql/src/backend/access/gin/ginget.c,v 1.6 2007/01/31 15:09:45 teodor Exp $
  *-------------------------------------------------------------------------
  */
 
@@ -420,6 +420,7 @@ scanGetItem(IndexScanDesc scan, ItemPointerData *item)
 }
 
 #define GinIsNewKey(s)         ( ((GinScanOpaque) scan->opaque)->keys == NULL )
+#define GinIsVoidRes(s)                ( ((GinScanOpaque) scan->opaque)->isVoidRes == true )
 
 Datum
 gingetmulti(PG_FUNCTION_ARGS)
@@ -432,10 +433,13 @@ gingetmulti(PG_FUNCTION_ARGS)
        if (GinIsNewKey(scan))
                newScanKey(scan);
 
-       startScan(scan);
-
        *returned_tids = 0;
 
+       if (GinIsVoidRes(scan))
+               PG_RETURN_BOOL(false);
+
+       startScan(scan);
+
        do
        {
                if (scanGetItem(scan, tids + *returned_tids))
@@ -462,6 +466,9 @@ gingettuple(PG_FUNCTION_ARGS)
        if (GinIsNewKey(scan))
                newScanKey(scan);
 
+       if (GinIsVoidRes(scan))
+               PG_RETURN_BOOL(false);
+
        startScan(scan);
        res = scanGetItem(scan, &scan->xs_ctup.t_self);
        stopScan(scan);
index a7ded0c47f7cea74df9ae79a1a77eb0a71079b8a..3a17233ba879f0d2fb59d2b94566ea5038778dc9 100644 (file)
@@ -8,7 +8,7 @@
  * Portions Copyright (c) 1994, Regents of the University of California
  *
  * IDENTIFICATION
- *                     $PostgreSQL: pgsql/src/backend/access/gin/gininsert.c,v 1.6 2007/01/05 22:19:21 momjian Exp $
+ *                     $PostgreSQL: pgsql/src/backend/access/gin/gininsert.c,v 1.7 2007/01/31 15:09:45 teodor Exp $
  *-------------------------------------------------------------------------
  */
 
@@ -203,7 +203,7 @@ static uint32
 ginHeapTupleBulkInsert(GinBuildState *buildstate, Datum value, ItemPointer heapptr)
 {
        Datum      *entries;
-       uint32          nentries;
+       int32           nentries;
        MemoryContext oldCtx;
 
        oldCtx = MemoryContextSwitchTo(buildstate->funcCtx);
@@ -356,7 +356,7 @@ static uint32
 ginHeapTupleInsert(Relation index, GinState *ginstate, Datum value, ItemPointer item)
 {
        Datum      *entries;
-       uint32          i,
+       int32           i,
                                nentries;
 
        entries = extractEntriesSU(ginstate, value, &nentries);
index bc8c5595f992ea7e014434d402ec327c8c2d5374..22896bc5d77d06fd77c08e551137ed05156f6e4f 100644 (file)
@@ -8,7 +8,7 @@
  * Portions Copyright (c) 1994, Regents of the University of California
  *
  * IDENTIFICATION
- *                     $PostgreSQL: pgsql/src/backend/access/gin/ginscan.c,v 1.8 2007/01/05 22:19:21 momjian Exp $
+ *                     $PostgreSQL: pgsql/src/backend/access/gin/ginscan.c,v 1.9 2007/01/31 15:09:45 teodor Exp $
  *-------------------------------------------------------------------------
  */
 
@@ -145,10 +145,12 @@ newScanKey(IndexScanDesc scan)
                                (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
                                 errmsg("GIN indexes do not support whole-index scans")));
 
+       so->isVoidRes = false;
+
        for (i = 0; i < scan->numberOfKeys; i++)
        {
                Datum      *entryValues;
-               uint32          nEntryValues;
+               int32           nEntryValues;
 
                if (scankey[i].sk_flags & SK_ISNULL)
                        elog(ERROR, "Gin doesn't support NULL as scan key");
@@ -162,6 +164,15 @@ newScanKey(IndexScanDesc scan)
                                                                           UInt16GetDatum(scankey[i].sk_strategy)
                                                                                                                          )
                        );
+               if ( nEntryValues < 0 )
+               {
+                       /*
+                        * extractQueryFn signals that nothing will be found,
+                        * so we can just set isVoidRes flag...
+                        */
+                       so->isVoidRes = true;   
+                       break;
+               }
                if (entryValues == NULL || nEntryValues == 0)
                        /* full scan... */
                        continue;
@@ -173,7 +184,7 @@ newScanKey(IndexScanDesc scan)
 
        so->nkeys = nkeys;
 
-       if (so->nkeys == 0)
+       if (so->nkeys == 0 && !so->isVoidRes)
                ereport(ERROR,
                                (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
                                 errmsg("GIN index does not support search with void query")));
index a14900e56c6101d1084602a2bec6b6ef73c76437..e704e8051ebc4367b4bec99aef910e239056fa47 100644 (file)
@@ -8,7 +8,7 @@
  * Portions Copyright (c) 1994, Regents of the University of California
  *
  * IDENTIFICATION
- *                     $PostgreSQL: pgsql/src/backend/access/gin/ginutil.c,v 1.9 2007/01/05 22:19:21 momjian Exp $
+ *                     $PostgreSQL: pgsql/src/backend/access/gin/ginutil.c,v 1.10 2007/01/31 15:09:45 teodor Exp $
  *-------------------------------------------------------------------------
  */
 
@@ -148,7 +148,7 @@ cmpEntries(const Datum *a, const Datum *b, cmpEntriesData *arg)
 }
 
 Datum *
-extractEntriesS(GinState *ginstate, Datum value, uint32 *nentries,
+extractEntriesS(GinState *ginstate, Datum value, int32 *nentries,
                                bool *needUnique)
 {
        Datum      *entries;
@@ -178,7 +178,7 @@ extractEntriesS(GinState *ginstate, Datum value, uint32 *nentries,
 
 
 Datum *
-extractEntriesSU(GinState *ginstate, Datum value, uint32 *nentries)
+extractEntriesSU(GinState *ginstate, Datum value, int32 *nentries)
 {
        bool            needUnique;
        Datum      *entries = extractEntriesS(ginstate, value, nentries,
index 0780e52a89683323beab881efb3895e9569c9452..e035557ff2c3c985a2edaef0f656327fa2665c37 100644 (file)
@@ -15,7 +15,7 @@
  *
  *
  * IDENTIFICATION
- *       $PostgreSQL: pgsql/src/backend/utils/adt/selfuncs.c,v 1.223 2007/01/28 02:53:34 tgl Exp $
+ *       $PostgreSQL: pgsql/src/backend/utils/adt/selfuncs.c,v 1.224 2007/01/31 15:09:45 teodor Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -76,6 +76,7 @@
 #include <ctype.h>
 #include <math.h>
 
+#include "access/gin.h"
 #include "catalog/pg_opfamily.h"
 #include "catalog/pg_statistic.h"
 #include "catalog/pg_type.h"
@@ -5286,7 +5287,120 @@ gincostestimate(PG_FUNCTION_ARGS)
        Cost       *indexTotalCost = (Cost *) PG_GETARG_POINTER(5);
        Selectivity *indexSelectivity = (Selectivity *) PG_GETARG_POINTER(6);
        double     *indexCorrelation = (double *) PG_GETARG_POINTER(7);
+       ListCell   *l;
+       int32           nfullscan = 0;
+
+       /*
+        * GIN doesn't support full index scan.
+        * If quals require full index scan then we should
+        * return cost big as possible to forbid full index scan.
+        */
+
+       foreach(l, indexQuals)
+       {
+               RestrictInfo *rinfo = (RestrictInfo *) lfirst(l);
+               Expr       *clause;
+               Node       *leftop,
+                                  *rightop,
+                                  *operand;
+               Oid                     extractProcOid;
+               Oid                     clause_op;
+               int                     strategy_op;
+               Oid                     lefttype, 
+                                       righttype;
+               bool        recheck;
+               int32           nentries;
+
+               /*
+                * For each clause it's needed to check operand
+                * for values to search in GIN. So, we should find 
+                * extractQuery method to get values from operand
+                */
+
+               Assert(IsA(rinfo, RestrictInfo));
+               clause = rinfo->clause;
+               Assert( IsA(clause, OpExpr) );
+               leftop = get_leftop(clause);
+               rightop = get_rightop(clause);
+               clause_op = ((OpExpr *) clause)->opno;
+
+               if (match_index_to_operand(leftop, 0 /* GiN has only one column */, index))
+               {
+                       operand = rightop;
+               }
+               else if (match_index_to_operand(rightop, 0, index))
+               {
+                       operand = leftop;
+                       clause_op = get_commutator(clause_op);
+               }
+
+               if ( IsA(operand, RelabelType) )
+                       operand = (Node *) ((RelabelType *) operand)->arg;
+
+               /*
+                * It's impossible to call extractQuery method for not yet
+                * known operand (taken from table, for example). In this
+                * case we can't do anything useful...
+                */
+               if ( !IsA(operand, Const) )
+                       continue;
+
+               if (!op_in_opfamily(clause_op, index->opfamily[0]))
+                       continue;
+
+               /*
+                * lefttype is a type of index column, righttype is a
+                * type of operand (query)
+                */
+               get_op_opfamily_properties(     clause_op, index->opfamily[0],
+                                                                       &strategy_op, &lefttype, &righttype, &recheck);
+
+               /* 
+                * GIN (as GiST) always has lefttype == righttype in pg_amproc
+                * and they are equal to type Oid on which index was created/designed
+                */
+               extractProcOid = get_opfamily_proc( index->opfamily[0],
+                                                                                       lefttype, lefttype, 
+                                                                                       GIN_EXTRACTQUERY_PROC );
+
+               if ( !OidIsValid(extractProcOid) )
+                       continue; /* should not be */
+
+               OidFunctionCall3( extractProcOid,
+                                                       ((Const*)operand)->constvalue,
+                                                       PointerGetDatum(&nentries),
+                                                       UInt16GetDatum(strategy_op));
+
+               if ( nentries == 0 )
+                       nfullscan++;
+               else if ( nentries < 0 )
+               {
+                       /*
+                        * GIN_EXTRACTQUERY_PROC guarantees that nothing will be found
+                        */
+                       *indexStartupCost = 0;
+                       *indexTotalCost = 0;
+                       *indexSelectivity = 0;
+                       *indexCorrelation = 0;
+                       PG_RETURN_VOID();
+               }
+       }
+
+       if ( nfullscan == list_length(indexQuals) )
+       {
+               /*
+                * All quals are void and require full scan. So
+                * set max possible cost to prevent index scan.
+                */
+               *indexStartupCost = disable_cost;
+               *indexTotalCost = disable_cost;
+               *indexSelectivity = 1.0;
+               *indexCorrelation = 0;
+
+               PG_RETURN_VOID();
+       }
 
+       
        genericcostestimate(root, index, indexQuals, outer_rel, 0.0,
                                                indexStartupCost, indexTotalCost,
                                                indexSelectivity, indexCorrelation);
index c37b3672781772d62b79fbe65f46fd2d7766815d..80f237499681cdca6c4cbb7592784550992f353f 100644 (file)
@@ -3,7 +3,7 @@
  *       header file for postgres inverted index access method implementation.
  *
  *     Copyright (c) 2006, PostgreSQL Global Development Group
- *     $PostgreSQL: pgsql/src/include/access/gin.h,v 1.9 2006/10/05 17:57:40 tgl Exp $
+ *     $PostgreSQL: pgsql/src/include/access/gin.h,v 1.10 2007/01/31 15:09:45 teodor Exp $
  *--------------------------------------------------------------------------
  */
 
@@ -233,8 +233,8 @@ extern void GinInitBuffer(Buffer b, uint32 f);
 extern void GinInitPage(Page page, uint32 f, Size pageSize);
 extern int     compareEntries(GinState *ginstate, Datum a, Datum b);
 extern Datum *extractEntriesS(GinState *ginstate, Datum value,
-                                                         uint32 *nentries, bool *needUnique);
-extern Datum *extractEntriesSU(GinState *ginstate, Datum value, uint32 *nentries);
+                                                         int32 *nentries, bool *needUnique);
+extern Datum *extractEntriesSU(GinState *ginstate, Datum value, int32 *nentries);
 extern Page GinPageGetCopyPage(Page page);
 
 /* gininsert.c */
@@ -399,6 +399,8 @@ typedef struct GinScanOpaqueData
 
        GinScanKey      keys;
        uint32          nkeys;
+       bool            isVoidRes; /* true if ginstate.extractQueryFn 
+                                                         guarantees that nothing will be found */
 
        GinScanKey      markPos;
 } GinScanOpaqueData;
@@ -458,7 +460,7 @@ typedef struct
 
 extern void ginInitBA(BuildAccumulator *accum);
 extern void ginInsertRecordBA(BuildAccumulator *accum,
-                                 ItemPointer heapptr, Datum *entries, uint32 nentry);
+                                 ItemPointer heapptr, Datum *entries, int32 nentry);
 extern ItemPointerData *ginGetEntry(BuildAccumulator *accum, Datum *entry, uint32 *n);
 
 #endif