Re: [HACKERS] pgbench -i order of vacuum
On Fri, Jul 20, 2012 at 12:26 PM, Tom Lane t...@sss.pgh.pa.us wrote: Jeff Janes jeff.ja...@gmail.com writes: On Fri, Jul 20, 2012 at 7:57 AM, Amit Kapila amit.kap...@huawei.com wrote: The command it executes is vacuum analyze .., so it will do analyze also on table which means it will collect stats corresponding to table and index. Are there stats collected on indexes? Only for expression indexes, which there aren't any of in the standard pgbench scenario. I don't see a reason not to change the ordering as you suggest. OK, done. -- Robert Haas EnterpriseDB: http://www.enterprisedb.com The Enterprise PostgreSQL Company -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
Re: [HACKERS] pgbench -i order of vacuum
From: pgsql-hackers-ow...@postgresql.org [mailto:pgsql-hackers-ow...@postgresql.org] On Behalf Of Jeff Janes Sent: Friday, July 20, 2012 5:36 AM Is there a reason to vacuum the pgbench_* tables after the indexes on them are built, rather than before? Since the indexes are on fresh tables, they can't have anything that needs to be cleaned. The command it executes is vacuum analyze .., so it will do analyze also on table which means it will collect stats corresponding to table and index. So if you do it before creation of index pgbench might behave different. In specific, from function do_analyze_rel(), it will not call compute_index_stats() if you execute the command before Creation of index. With Regards, Amit Kapila. -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
Re: [HACKERS] pgbench -i order of vacuum
On Fri, Jul 20, 2012 at 7:57 AM, Amit Kapila amit.kap...@huawei.com wrote: From: pgsql-hackers-ow...@postgresql.org [mailto:pgsql-hackers-ow...@postgresql.org] On Behalf Of Jeff Janes Sent: Friday, July 20, 2012 5:36 AM Is there a reason to vacuum the pgbench_* tables after the indexes on them are built, rather than before? Since the indexes are on fresh tables, they can't have anything that needs to be cleaned. The command it executes is vacuum analyze .., so it will do analyze also on table which means it will collect stats corresponding to table and index. Are there stats collected on indexes? I thought all stats were on tables only, and the only reason to visit the index was to remove all-visible-dead entries. Cheers, Jeff -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
Re: [HACKERS] pgbench -i order of vacuum
Jeff Janes jeff.ja...@gmail.com writes: On Fri, Jul 20, 2012 at 7:57 AM, Amit Kapila amit.kap...@huawei.com wrote: The command it executes is vacuum analyze .., so it will do analyze also on table which means it will collect stats corresponding to table and index. Are there stats collected on indexes? Only for expression indexes, which there aren't any of in the standard pgbench scenario. I don't see a reason not to change the ordering as you suggest. regards, tom lane -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
[HACKERS] pgbench -i order of vacuum
Is there a reason to vacuum the pgbench_* tables after the indexes on them are built, rather than before? Since the indexes are on fresh tables, they can't have anything that needs to be cleaned. I don't think the current order accomplishes anything, except to slow down large initializations by ~25%. The attached patch moves the vacuums up. I also made -n skip the vacuums altogether. Since -n is allowed under -i, it would be nice if it did something, and there is only one intuitive thing for it to do. I don't know what the use case for is, but I think I've heard grumbling about it before. Cheers, Jeff pgbench_vacuum_order_v1.patch Description: Binary data -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers