Re: [PERFORM] PostgreSQL publishes first real benchmark

2007-07-10 Thread Heiko W.Rupp
Hi, I think this result will be useful for performance discussions of postgresql against other databases. http://www.spec.org/jAppServer2004/results/res2007q3/ More on Josh Berkus's blog: http://blogs.ittoolbox.com/database/soup/archives/postgresql- publishes-first-real-benchmark-17470

Re: [PERFORM] Filesystem Direct I/O and WAL sync option

2007-07-10 Thread Dimitri
Yes, I tried all WAL sync methods, but there was no difference... However, there was a huge difference when I run the same tests under Solaris10 - 'fdatasync' option gave the best performance level. On the same time direct I/O did not make difference on Solaris 10 :) So the main rule - there is n

[PERFORM] Query Analyser

2007-07-10 Thread Gauri Kanekar
Hi List, Is there anyway so as to indicate the Query Analyser not to use the plan which it is using regularly, and use a new plan ? From where do the Query Analyser gets the all info to prepare a plan? Is it only from the pg_statistics table or are there anyother tables which have this info. s

[PERFORM] tuning a function to insert/retrieve values from a reference table

2007-07-10 Thread Marc Mamin
Hello, I have a simple table id/value, and a function that returns the id of a given value, inserting the later if not yet present. The probability that a value already exist within the reference table is very high. Different db users may have their own reference table with different content, bu

Re: [PERFORM] tuning a function to insert/retrieve values from a reference table

2007-07-10 Thread Tom Lane
"Marc Mamin" <[EMAIL PROTECTED]> writes: > Can I optimize this function with: > a) remove the EXCEPTION clause (Is there an underlying lock that prevent > concurrent inserts ?) No. > b) declare the function being IMMUTABLE ? Certainly not --- it's got side-effects. rega

[PERFORM] Equivalent queries produce different plans

2007-07-10 Thread Craig James
The two queries below produce different plans. select r.version_id, r.row_num, m.molkeys from my_rownum r join my_molkeys m on (r.version_id = m.version_id) where r.version_id >= 320 and r.version_id < 330 order by r.version_id; select r.version_id, r.row_num, m.molkeys from my_rownu

Re: [PERFORM] Equivalent queries produce different plans

2007-07-10 Thread Craig James
Sorry, I forgot to mention: This is 8.1.4, with a fairly ordinary configuration on a 4 GB system. Craig Craig James wrote: The two queries below produce different plans. select r.version_id, r.row_num, m.molkeys from my_rownum r join my_molkeys m on (r.version_id = m.version_id) where r.vers

Re: [PERFORM] Equivalent queries produce different plans

2007-07-10 Thread Tom Lane
Craig James <[EMAIL PROTECTED]> writes: > The two queries below produce different plans. > select r.version_id, r.row_num, m.molkeys from my_rownum r > join my_molkeys m on (r.version_id = m.version_id) > where r.version_id >= 320 > and r.version_id < 330 > order by r.version_id; > sel