Discordance between the way select is called.
От | Patrice Drolet |
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Тема | Discordance between the way select is called. |
Дата | |
Msg-id | 42753A5A.6030004@infodata.ca обсуждение исходный текст |
Ответы |
Re: Discordance between the way select is called.
|
Список | pgsql-sql |
Hi, I have a java app that uses hibernate to do queries. One query on a 6.5 millions records takes about 15 seconds while the same one (take from the sql that shows in the consol - I configured hibernate to show_sql) takes about 50 ms when done with pgadmin3. This is a simple select. Here is the log of pgsql: <postgres%patient_record> LOG: 00000: statement: select notevalue0_.id as id, notevalue0_.value_note as value2_3_, notevalue0_.actif as actif3_, notevalue0_.id_note as id4_3_, notevalue0_.id_field_name as id5_3_ from note.note_value notevalue0_ where notevalue0_.id_note=$1 and notevalue0_.actif=1 <postgres%patient_record> LOCATION: pg_parse_query, postgres.c:473 <postgres%patient_record> LOG: 00000: PLANNER STATISTICS <postgres%patient_record> DETAIL: ! system usage stats: ! 0.001171 elapsed 0.000000 user 0.000000 system sec ! [0.050000 user 0.010000 sys total] ! 0/0 [0/0] filesystem blocks in/out ! 0/0 [0/0] page faults/reclaims, 0 [0]swaps ! 0 [0] signals rcvd, 0/0 [8/84] messages rcvd/sent ! 0/0 [7/0] voluntary/involuntary context switches ! buffer usage stats: ! Shared blocks: 2 read, 0 written, buffer hit rate = 95.74% ! Local blocks: 0 read, 0 written, buffer hit rate = 0.00% ! Direct blocks: 0 read, 0 written <postgres%patient_record> LOCATION: ShowUsage, postgres.c:3341 <postgres%patient_record> LOG: 00000: EXECUTOR STATISTICS <postgres%patient_record> DETAIL: ! system usage stats: ! 12.323373 elapsed 10.890000 user 1.140000 system sec ! [10.940000 user 1.150000 sys total] ! 0/0 [0/0] filesystem blocks in/out ! 0/0 [0/0] page faults/reclaims,0 [0] swaps ! 0 [0] signals rcvd, 0/0 [8/87] messages rcvd/sent ! 0/0 [7/0] voluntary/involuntarycontext switches ! buffer usage stats: ! Shared blocks: 44305 read, 0 written,buffer hit rate = 0.00% ! Local blocks: 0 read, 0 written, buffer hit rate = 0.00% ! Direct blocks: 0 read, 0 written The $1 value is a simple integer and is a foreign key for another table. There were 4 rows only meeting this criteria. Can you explain to me the executor statistics? Why does it do 44305 read? This query will be a stopper for us if not faster... :-( Apart from this, we love postgres... Thanks for any help. Patrice Drolet Logiciels INFO-DATA inc.
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