plantuner.c

   1 /*
   2  * Copyright (c) 2009 Teodor Sigaev <teodor@sigaev.ru>
   3  */
   4
   5 #include <postgres.h>
   6
   7 #include <fmgr.h>
   8 #include <catalog/namespace.h>
   9 #include <catalog/pg_class.h>
  10 #include <nodes/pg_list.h>
  11 #include <optimizer/plancat.h>
  12 #include <utils/builtins.h>
  13 #include <utils/guc.h>
  14 #include <utils/lsyscache.h>
  15
  16 PG_MODULE_MAGIC;
  17
  18 static int      nIndexesOut = 0;
  19 static Oid      *indexesOut = NULL;
  20 get_relation_info_hook_type     prevHook = NULL;
  21
  22 static char *indexesOutStr = "";
  23
  24 static const char *
  25 indexesOutAssign(const char * newval, bool doit, GucSource source)
  26 {
  27         char       *rawname;
  28         List       *namelist;
  29         ListCell   *l;
  30         Oid                     *newOids = NULL;
  31         int                     nOids = 0,
  32                                 i = 0;
  33
  34         rawname = pstrdup(newval);
  35
  36         if (!SplitIdentifierString(rawname, ',', &namelist))
  37                 goto cleanup;
  38
  39         if (doit)
  40         {
  41                 nOids = list_length(namelist);
  42                 newOids = malloc(sizeof(Oid) * (nOids+1));
  43                 if (!newOids)
  44                         elog(ERROR,"could not allocate %d bytes", sizeof(Oid) * (nOids+1));
  45         }
  46
  47         foreach(l, namelist)
  48         {
  49                 char            *curname = (char *) lfirst(l);
  50                 Oid                     indexOid = RangeVarGetRelid(makeRangeVarFromNameList(stringToQualifiedNameList(curname)), true);
  51
  52                 if (indexOid == InvalidOid)
  53                 {
  54                         elog(WARNING,"'%s' does not exist", curname);
  55                         continue;
  56                 }
  57                 else if ( get_rel_relkind(indexOid) != RELKIND_INDEX )
  58                 {
  59                         elog(WARNING,"'%s' is not an index", curname);
  60                         continue;
  61                 }
  62                 else if (doit)
  63                 {
  64                         newOids[i++] = indexOid;
  65                 }
  66         }
  67
  68         if (doit)
  69         {
  70                 nIndexesOut = nOids;
  71                 indexesOut = newOids;
  72         }
  73
  74         pfree(rawname);
  75         list_free(namelist);
  76
  77         return newval;
  78
  79 cleanup:
  80         if (newOids)
  81                 free(newOids);
  82         pfree(rawname);
  83         list_free(namelist);
  84         return NULL;
  85 }
  86
  87
  88 static void
  89 indexFilter(PlannerInfo *root, Oid relationObjectId, bool inhparent, RelOptInfo *rel) {
  90         int i;
  91
  92         for(i=0;i<nIndexesOut;i++)
  93         {
  94                 ListCell   *l;
  95
  96                 foreach(l, rel->indexlist)
  97                 {
  98                         IndexOptInfo    *info = (IndexOptInfo*)lfirst(l);
  99
 100                         if (indexesOut[i] == info->indexoid)
 101                         {
 102                                 rel->indexlist = list_delete_ptr(rel->indexlist, info);
 103                                 break;
 104                         }
 105                 }
 106         }
 107
 108         /*
 109          * Call next hook if it exists
 110          */
 111         if (prevHook)
 112                 prevHook(root, relationObjectId, inhparent, rel);
 113 }
 114
 115 static const char*
 116 IndexFilterShow(void)
 117 {
 118         char    *val, *ptr;
 119         int     i,
 120                         len;
 121
 122         len = 1 /* \0 */ + nIndexesOut * (2 * NAMEDATALEN + 2 /* ', ' */ + 1 /* . */);
 123         ptr = val = palloc(len);
 124
 125         *ptr ='\0';
 126         for(i=0; i<nIndexesOut; i++)
 127         {
 128                 char    *relname = get_rel_name(indexesOut[i]);
 129                 Oid     nspOid = get_rel_namespace(indexesOut[i]);
 130                 char    *nspname = get_namespace_name(nspOid);
 131
 132                 if ( relname == NULL || nspOid == InvalidOid || nspname == NULL )
 133                         continue;
 134
 135                 ptr += snprintf(ptr, len - (ptr - val), "%s%s.%s",
 136                                                                                                 (i==0) ? "" : ", ",
 137                                                                                                 nspname,
 138                                                                                                 relname);
 139         }
 140
 141         return val;
 142 }
 143
 144 void _PG_init(void);
 145 void
 146 _PG_init(void)
 147 {
 148     DefineCustomStringVariable(
 149                 "plantuner.forbid_index",
 150                 "List of forbidden indexes",
 151                 "Listed indexes will not be used in queries",
 152                 &indexesOutStr,
 153                 "",
 154                 PGC_USERSET,
 155                 0,
 156                 indexesOutAssign,
 157                 IndexFilterShow
 158         );
 159
 160         if (get_relation_info_hook != indexFilter )
 161         {
 162                 prevHook = get_relation_info_hook;
 163                 get_relation_info_hook = indexFilter;
 164         }
 165 }