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bkempner/gist:1650406

Created January 21, 2012 00:20
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  1. Ben Kempner revised this gist Jan 21, 2012. 1 changed file with 41 additions and 1 deletion.
    42 changes: 41 additions & 1 deletion gistfile1.txt
    View file
    Original file line number Diff line number Diff line change
    @@ -23,4 +23,44 @@ de2nq092qkqfxll=> explain select count(*) from units where city_name = 'San Fran
    Recheck Cond: ((city_name)::text = 'San Francisco'::text)
    Filter: is_deleted
    -> Bitmap Index Scan on ben_test_partial_2 (cost=0.00..8.80 rows=331 width=0)
    Index Cond: (((city_name)::text = 'San Francisco'::text) AND (is_deleted = true))
    Index Cond: (((city_name)::text = 'San Francisco'::text) AND (is_deleted = true))



    USING EXPLAIN ANALYZE


    de2nq092qkqfxll=> explain analyze select count(*) from units where city_name = 'San Francisco' and is_deleted = true;
    QUERY PLAN
    -------------------------------------------------------------------------------------------------------------------------------------
    Aggregate (cost=1249.61..1249.61 rows=1 width=0) (actual time=1.964..1.965 rows=1 loops=1)
    -> Bitmap Heap Scan on units (cost=8.82..1249.44 rows=331 width=0) (actual time=0.321..1.410 rows=847 loops=1)
    Recheck Cond: ((city_name)::text = 'San Francisco'::text)
    Filter: is_deleted
    -> Bitmap Index Scan on ben_test_partial_2 (cost=0.00..8.80 rows=331 width=0) (actual time=0.291..0.291 rows=847 loops=1)
    Index Cond: (((city_name)::text = 'San Francisco'::text) AND (is_deleted = true))
    Total runtime: 2.037 ms
    (7 rows)

    de2nq092qkqfxll=>
    de2nq092qkqfxll=>
    de2nq092qkqfxll=> drop index ben_test_partial_2;
    DROP INDEX
    de2nq092qkqfxll=> create index ben_test_partial on (city_name) where is_deleted = true;
    ERROR: syntax error at or near "("
    LINE 1: create index ben_test_partial on (city_name) where is_delete...
    ^
    de2nq092qkqfxll=> create index ben_test_partial on units (city_name) where is_deleted = true;
    CREATE INDEX
    de2nq092qkqfxll=>
    de2nq092qkqfxll=>
    de2nq092qkqfxll=> explain analyze select count(*) from units where city_name = 'San Francisco' and is_deleted = true;
    QUERY PLAN
    ------------------------------------------------------------------------------------------------------------------------------------
    Aggregate (cost=1276.17..1276.17 rows=1 width=0) (actual time=1.592..1.593 rows=1 loops=1)
    -> Bitmap Heap Scan on units (cost=35.38..1276.00 rows=331 width=0) (actual time=0.215..1.039 rows=847 loops=1)
    Recheck Cond: (((city_name)::text = 'San Francisco'::text) AND is_deleted)
    -> Bitmap Index Scan on ben_test_partial (cost=0.00..35.37 rows=331 width=0) (actual time=0.190..0.190 rows=847 loops=1)
    Index Cond: ((city_name)::text = 'San Francisco'::text)
    Total runtime: 1.661 ms
    (6 rows)
  2. Ben Kempner revised this gist Jan 21, 2012. 1 changed file with 16 additions and 1 deletion.
    17 changes: 16 additions & 1 deletion gistfile1.txt
    View file
    Original file line number Diff line number Diff line change
    @@ -8,4 +8,19 @@ de2nq092qkqfxll=> explain select count(*) from units where city_name = 'San Fran
    Recheck Cond: (((city_name)::text = 'San Francisco'::text) AND is_deleted)
    -> Bitmap Index Scan on ben_test_partial (cost=0.00..35.37 rows=331 width=0)
    Index Cond: ((city_name)::text = 'San Francisco'::text)
    (5 rows)
    (5 rows)


    de2nq092qkqfxll=> drop index ben_test_partial;
    DROP INDEX
    de2nq092qkqfxll=> create index ben_test_partial_2 on units (city_name, is_deleted);
    CREATE INDEX
    de2nq092qkqfxll=> explain select count(*) from units where city_name = 'San Francisco' and is_deleted = true;
    QUERY PLAN
    -------------------------------------------------------------------------------------------------
    Aggregate (cost=1249.61..1249.61 rows=1 width=0)
    -> Bitmap Heap Scan on units (cost=8.82..1249.44 rows=331 width=0)
    Recheck Cond: ((city_name)::text = 'San Francisco'::text)
    Filter: is_deleted
    -> Bitmap Index Scan on ben_test_partial_2 (cost=0.00..8.80 rows=331 width=0)
    Index Cond: (((city_name)::text = 'San Francisco'::text) AND (is_deleted = true))
  3. Ben Kempner created this gist Jan 21, 2012.
    11 changes: 11 additions & 0 deletions gistfile1.txt
    View file
    Original file line number Diff line number Diff line change
    @@ -0,0 +1,11 @@
    de2nq092qkqfxll=> create index ben_test_partial on units (city_name) where is_deleted = true;
    CREATE INDEX
    de2nq092qkqfxll=> explain select count(*) from units where city_name = 'San Francisco' and is_deleted = true;
    QUERY PLAN
    ----------------------------------------------------------------------------------------
    Aggregate (cost=1276.17..1276.17 rows=1 width=0)
    -> Bitmap Heap Scan on units (cost=35.38..1276.00 rows=331 width=0)
    Recheck Cond: (((city_name)::text = 'San Francisco'::text) AND is_deleted)
    -> Bitmap Index Scan on ben_test_partial (cost=0.00..35.37 rows=331 width=0)
    Index Cond: ((city_name)::text = 'San Francisco'::text)
    (5 rows)