plantuner.c

   1 /*
   2  * Copyright (c) 2009 Teodor Sigaev <teodor@sigaev.ru>
   3  * All rights reserved.
   4  *
   5  * Redistribution and use in source and binary forms, with or without
   6  * modification, are permitted provided that the following conditions
   7  * are met:
   8  * 1. Redistributions of source code must retain the above copyright
   9  *        notice, this list of conditions and the following disclaimer.
  10  * 2. Redistributions in binary form must reproduce the above copyright
  11  *        notice, this list of conditions and the following disclaimer in the
  12  *        documentation and/or other materials provided with the distribution.
  13  * 3. Neither the name of the author nor the names of any co-contributors
  14  *        may be used to endorse or promote products derived from this software
  15  *        without specific prior written permission.
  16  *
  17  * THIS SOFTWARE IS PROVIDED BY CONTRIBUTORS ``AS IS'' AND ANY EXPRESS
  18  * OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
  19  * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  20  * ARE DISCLAIMED. IN NO EVENT SHALL CONTRIBUTORS BE LIABLE FOR ANY
  21  * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  22  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE
  23  * GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
  24  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER
  25  * IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
  26  * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN
  27  * IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  28  */
  29
  30 #include <postgres.h>
  31
  32 #include <fmgr.h>
  33 #include <catalog/namespace.h>
  34 #include <catalog/pg_class.h>
  35 #include <nodes/pg_list.h>
  36 #include <optimizer/plancat.h>
  37 #include <utils/builtins.h>
  38 #include <utils/guc.h>
  39 #include <utils/lsyscache.h>
  40
  41 PG_MODULE_MAGIC;
  42
  43 static int      nIndexesOut = 0;
  44 static Oid      *indexesOut = NULL;
  45 get_relation_info_hook_type     prevHook = NULL;
  46
  47 static char *indexesOutStr = "";
  48
  49 static const char *
  50 indexesOutAssign(const char * newval, bool doit, GucSource source)
  51 {
  52         char       *rawname;
  53         List       *namelist;
  54         ListCell   *l;
  55         Oid                     *newOids = NULL;
  56         int                     nOids = 0,
  57                                 i = 0;
  58
  59         rawname = pstrdup(newval);
  60
  61         if (!SplitIdentifierString(rawname, ',', &namelist))
  62                 goto cleanup;
  63
  64         if (doit)
  65         {
  66                 nOids = list_length(namelist);
  67                 newOids = malloc(sizeof(Oid) * (nOids+1));
  68                 if (!newOids)
  69                         elog(ERROR,"could not allocate %d bytes", sizeof(Oid) * (nOids+1));
  70         }
  71
  72         foreach(l, namelist)
  73         {
  74                 char            *curname = (char *) lfirst(l);
  75                 Oid                     indexOid = RangeVarGetRelid(makeRangeVarFromNameList(stringToQualifiedNameList(curname)), true);
  76
  77                 if (indexOid == InvalidOid)
  78                 {
  79                         elog(WARNING,"'%s' does not exist", curname);
  80                         continue;
  81                 }
  82                 else if ( get_rel_relkind(indexOid) != RELKIND_INDEX )
  83                 {
  84                         elog(WARNING,"'%s' is not an index", curname);
  85                         continue;
  86                 }
  87                 else if (doit)
  88                 {
  89                         newOids[i++] = indexOid;
  90                 }
  91         }
  92
  93         if (doit)
  94         {
  95                 nIndexesOut = nOids;
  96                 indexesOut = newOids;
  97         }
  98
  99         pfree(rawname);
 100         list_free(namelist);
 101
 102         return newval;
 103
 104 cleanup:
 105         if (newOids)
 106                 free(newOids);
 107         pfree(rawname);
 108         list_free(namelist);
 109         return NULL;
 110 }
 111
 112
 113 static void
 114 indexFilter(PlannerInfo *root, Oid relationObjectId, bool inhparent, RelOptInfo *rel) {
 115         int i;
 116
 117         for(i=0;i<nIndexesOut;i++)
 118         {
 119                 ListCell   *l;
 120
 121                 foreach(l, rel->indexlist)
 122                 {
 123                         IndexOptInfo    *info = (IndexOptInfo*)lfirst(l);
 124
 125                         if (indexesOut[i] == info->indexoid)
 126                         {
 127                                 rel->indexlist = list_delete_ptr(rel->indexlist, info);
 128                                 break;
 129                         }
 130                 }
 131         }
 132
 133         /*
 134          * Call next hook if it exists
 135          */
 136         if (prevHook)
 137                 prevHook(root, relationObjectId, inhparent, rel);
 138 }
 139
 140 static const char*
 141 IndexFilterShow(void)
 142 {
 143         char    *val, *ptr;
 144         int     i,
 145                         len;
 146
 147         len = 1 /* \0 */ + nIndexesOut * (2 * NAMEDATALEN + 2 /* ', ' */ + 1 /* . */);
 148         ptr = val = palloc(len);
 149
 150         *ptr ='\0';
 151         for(i=0; i<nIndexesOut; i++)
 152         {
 153                 char    *relname = get_rel_name(indexesOut[i]);
 154                 Oid     nspOid = get_rel_namespace(indexesOut[i]);
 155                 char    *nspname = get_namespace_name(nspOid);
 156
 157                 if ( relname == NULL || nspOid == InvalidOid || nspname == NULL )
 158                         continue;
 159
 160                 ptr += snprintf(ptr, len - (ptr - val), "%s%s.%s",
 161                                                                                                 (i==0) ? "" : ", ",
 162                                                                                                 nspname,
 163                                                                                                 relname);
 164         }
 165
 166         return val;
 167 }
 168
 169 void _PG_init(void);
 170 void
 171 _PG_init(void)
 172 {
 173     DefineCustomStringVariable(
 174                 "plantuner.forbid_index",
 175                 "List of forbidden indexes",
 176                 "Listed indexes will not be used in queries",
 177                 &indexesOutStr,
 178                 "",
 179                 PGC_USERSET,
 180                 0,
 181                 indexesOutAssign,
 182                 IndexFilterShow
 183         );
 184
 185         if (get_relation_info_hook != indexFilter )
 186         {
 187                 prevHook = get_relation_info_hook;
 188                 get_relation_info_hook = indexFilter;
 189         }
 190 }