Replace BackendIds with 0-based ProcNumbers Marina Polyakova <m.polyakova@postgrespro.ru>

[plantuner.git] / README.plantuner

diff --git a/README.plantuner b/README.plantuner
index 2d01f8e..17c8ba0 100644 (file)
--- a/README.plantuner
+++ b/README.plantuner
@@ -23,11 +23,28 @@ Motivation
    specific index(es), without dropping them, or to instruct planner to
    use specific index.
 
+   Next, for some workload PostgreSQL could be too pessimistic for
+   newly created tables and assumes much more rows in table than
+   it actually has. If plantuner.fix_empty_table GUC variable is set
+   to true then module will set to zero number of pages/tuples of
+   table which hasn't blocks in file.
+
 Installation
 
      * Get latest source of plantuner from CVS Repository
      * gmake && gmake install && gmake installcheck
 
+Syntax
+       plantuner.forbid_index (deprecated)
+       plantuner.disable_index
+               List of indexes invisible to planner
+       plantuner.enable_index
+               List of indexes visible to planner even they are hided
+               by plantuner.disable_index. 
+       plantuner.only_index
+               List of explicitly enabled indexes (overload plantuner.disable_index
+               and plantuner.enable_index), so, only indexes in this list are allowed.
+
 Usage
 
    To enable the module you can either load shared library 'plantuner' in
@@ -54,7 +71,7 @@ Indexes:
          Index Cond: (id = 1)
 (4 rows)
 =# set enable_seqscan=off;
-=# set plantuner.forbid_index='id_idx2';
+=# set plantuner.disable_index='id_idx2';
 =# explain select id from test where id=1;
                               QUERY PLAN
 ----------------------------------------------------------------------
@@ -63,10 +80,20 @@ Indexes:
    ->  Bitmap Index Scan on id_idx  (cost=0.00..4.34 rows=12 width=0)
          Index Cond: (id = 1)
 (4 rows)
-=# set plantuner.forbid_index='id_idx2,id_idx';
+=# set plantuner.disable_index='id_idx2,id_idx';
 =# explain select id from test where id=1;
                                QUERY PLAN
 -------------------------------------------------------------------------
  Seq Scan on test  (cost=10000000000.00..10000000040.00 rows=12 width=4)
    Filter: (id = 1)
 (2 rows)
+=# set plantuner.enable_index='id_idx';
+=# explain select id from test where id=1;
+                              QUERY PLAN
+-----------------------------------------------------------------------
+ Bitmap Heap Scan on test  (cost=4.34..15.03 rows=12 width=4)
+   Recheck Cond: (id = 1)
+   ->  Bitmap Index Scan on id_idx  (cost=0.00..4.34 rows=12 width=0)
+         Index Cond: (id = 1)
+(4 rows)
+