add plantuner.fix_empty_table GUC variable

[plantuner.git] / plantuner.c

diff --git a/plantuner.c b/plantuner.c
index bf3c511..96d679a 100644 (file)
--- a/plantuner.c
+++ b/plantuner.c
@@ -30,19 +30,23 @@
 #include <postgres.h>
 
 #include <fmgr.h>
+#include <access/heapam.h>
 #include <catalog/namespace.h>
 #include <catalog/pg_class.h>
 #include <nodes/pg_list.h>
 #include <optimizer/plancat.h>
+#include <storage/bufmgr.h>
 #include <utils/builtins.h>
 #include <utils/guc.h>
 #include <utils/lsyscache.h>
+#include <utils/rel.h>
 
 PG_MODULE_MAGIC;
 
 static int     nIndexesOut = 0;
 static Oid     *indexesOut = NULL;
 get_relation_info_hook_type    prevHook = NULL;
+static bool    fix_empty_table = false;
 
 static char *indexesOutStr = "";
 
@@ -66,7 +70,7 @@ indexesOutAssign(const char * newval, bool doit, GucSource source)
                nOids = list_length(namelist);
                newOids = malloc(sizeof(Oid) * (nOids+1));
                if (!newOids)
-                       elog(ERROR,"could not allocate %d bytes", sizeof(Oid) * (nOids+1));
+                       elog(ERROR,"could not allocate %d bytes", (int)(sizeof(Oid) * (nOids+1)));
        }
 
        foreach(l, namelist)
@@ -76,12 +80,18 @@ indexesOutAssign(const char * newval, bool doit, GucSource source)
 
                if (indexOid == InvalidOid)
                {
-                       elog(WARNING,"'%s' does not exist", curname);
+#if PG_VERSION_NUM >= 90100
+                       if (doit == false)
+#endif
+                               elog(WARNING,"'%s' does not exist", curname);
                        continue;
                }
                else if ( get_rel_relkind(indexOid) != RELKIND_INDEX )
                {
-                       elog(WARNING,"'%s' is not an index", curname);
+#if PG_VERSION_NUM >= 90100
+                       if (doit == false)
+#endif
+                               elog(WARNING,"'%s' is not an index", curname);
                        continue;
                }
                else if (doit)
@@ -109,6 +119,30 @@ cleanup:
        return NULL;
 }
 
+#if PG_VERSION_NUM >= 90100
+
+static bool
+indexesOutCheck(char **newval, void **extra, GucSource source)
+{
+       char *val;
+
+       val = (char*)indexesOutAssign(*newval, false, source);
+
+       if (val)
+       {
+               *newval = val;
+               return true;
+       }
+
+       return false;
+}
+static void
+indexesOutAssignNew(const char *newval, void *extra)
+{
+       indexesOutAssign(newval, true, PGC_S_USER /* doesn't matter */);
+}
+
+#endif
 
 static void
 indexFilter(PlannerInfo *root, Oid relationObjectId, bool inhparent, RelOptInfo *rel) {
@@ -130,6 +164,35 @@ indexFilter(PlannerInfo *root, Oid relationObjectId, bool inhparent, RelOptInfo
                }
        }
 
+       if (fix_empty_table && rel)
+       {
+               
+
+       }
+
+}
+
+static void
+execPlantuner(PlannerInfo *root, Oid relationObjectId, bool inhparent, RelOptInfo *rel) {
+       Relation        relation;
+
+       relation = heap_open(relationObjectId, NoLock);
+       if (relation->rd_rel->relkind == RELKIND_RELATION)
+       {
+               if (fix_empty_table && RelationGetNumberOfBlocks(relation) == 0)
+               {
+                       /*
+                        * estimate_rel_size() could be too pessimistic for particular
+                        * workload
+                        */
+                       rel->pages = 0.0;
+                       rel->tuples = 0.0;
+               }
+
+               indexFilter(root, relationObjectId, inhparent, rel);
+       }
+       heap_close(relation, NoLock);
+
        /*
         * Call next hook if it exists 
         */
@@ -178,13 +241,37 @@ _PG_init(void)
                "",
                PGC_USERSET,
                0,
+#if PG_VERSION_NUM >= 90100
+               indexesOutCheck,
+               indexesOutAssignNew,
+#else
                indexesOutAssign,
+#endif
                IndexFilterShow
        );
 
-       if (get_relation_info_hook != indexFilter )
+    DefineCustomBoolVariable(
+               "plantuner.fix_empty_table",
+               "Sets to zero estimations for empty tables",
+               "Sets to zero estimations for empty or newly created tables",
+               &fix_empty_table,
+#if PG_VERSION_NUM >= 80400
+               fix_empty_table,
+#endif
+               PGC_USERSET,
+#if PG_VERSION_NUM >= 80400
+               GUC_NOT_IN_SAMPLE,
+#if PG_VERSION_NUM >= 90100
+               NULL,
+#endif
+#endif
+               NULL,
+               NULL
+       );
+
+       if (get_relation_info_hook != execPlantuner )
        {
                prevHook = get_relation_info_hook;
-               get_relation_info_hook = indexFilter;
+               get_relation_info_hook = execPlantuner;
        }
 }