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Thanks for reply Tom, [postgres@db-server ~]$ psql -c"show all" | grep parallel
force_parallel_mode | off | Forces use of parallel query facilities.
max_parallel_workers | 192 | Sets the maximum number of parallel workers than can be active at one time.
max_parallel_workers_per_gather | 96 | Sets the maximum number of parallel processes per executor node.
min_parallel_index_scan_size | 512kB | Sets the minimum amount of index data for a parallel scan.
min_parallel_table_scan_size | 8MB | Sets the minimum amount of table data for a parallel scan.
parallel_setup_cost | 1000 | Sets the planner's estimate of the cost of starting up worker processes for parallel query.
parallel_tuple_cost | 0.1 | Sets the planner's estimate of the cost of passing each tuple (row) from worker to master backend.
Gönderen: Tom Lane <tgl@xxxxxxxxxxxxx>
Gönderildi: 19 Ekim 2018 Cuma 16:52:04 Kime: Yavuz Selim Sertoglu Bilgi: pgsql-performance@xxxxxxxxxxxxxxxxxxxx Konu: Re: Gained %20 performance after disabling bitmapscan Yavuz Selim Sertoglu <yavuzselim.sertoglu@xxxxxxxxxxxxxxxx> writes:
> I have a problem with my query. Query always using parallel bitmap heap scan. Have you messed with the parallel cost parameters? It seems a bit surprising that this query wants to use parallelism at all. > Index Cond: (((mukellef_id)::text = '0123456789'::text) AND (kayit_tarihi >= '2018-01-01 00:00:00'::timestamp without time zone) AND (sube_no = '-13'::integer) AND ((defter)::text = 'sm'::text)) If that's your normal query pattern, then this isn't a very good index design: > Column | Type | Definition > --------------+-----------------------------+-------------- > mukellef_id | character varying(12) | mukellef_id > kayit_tarihi | timestamp without time zone | kayit_tarihi > sube_no | integer | sube_no > defter | character varying(4) | defter > id | bigint | id The column order should be mukellef_id, sube_no, defter, kayit_tarihi, id so that the index entries you want are adjacent in the index. Of course, if you have other queries using this index, you might need to leave it as-is --- but this is the query you're complaining about... regards, tom lane YASAL UYARI:
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