getting execution plans with multiple database connections
От | Jenny Zhang |
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Тема | getting execution plans with multiple database connections |
Дата | |
Msg-id | 1060967420.8207.177.camel@ibm-a обсуждение исходный текст |
Ответы |
Re: getting execution plans with multiple database connections
|
Список | pgsql-general |
Hi, I am running OSDL-DBT3 test against PostgreSQL. I found performance difference between the runs even though the data and queries are the same. I tried to study this problem by getting execution plans at the beginning of each test. The following script gets execution plan for 22 queries, except query 15. i=1 while [ $i -le 22 ] do if [ $i -ne 15 ]; then $dbdriver_pgsql_path/explain_single_query.sh $i $run_dir/plan/power_query$i.txt fi let "i=$i+1" done The script 'explain_single_query.sh' takes 2 parameters: query_number and output file name. It works for power test(single database connection). In other words, I can get execution plans for all the 21 queries if there is only one stream connecting to the database. But for the throughput test(multiple database connections), some query execution plan files are blank. It seems to be random, for example, for the run at: http://khack.osdl.org/stp/277495/results/plan/ throughput_stream1_query14.txt, throughput_stream3_query4.txt, throughput_stream3_query5.txt, throughput_stream4_query4.txt, throughput_stream4_query18.txt are of size 0. And if I do the run again, a different set of files are blank. Can anyone give me an explanation? Thanks, -- Jenny Zhang Open Source Development Lab Inc 12725 SW Millikan Way Suite 400 Beaverton, OR 97005 (503)626-2455 ext 31
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