On Mon, Mar 18, 2002 at 11:39:09AM -0500, Gabriel Ricard wrote: > Greetings, > > We're running MySQL 3.23.47 on MacOS X 10.1.2. We've got a rather large > table ( 200,000+ records, 120+ columns) and some simple queries on that > table have pretty inconsistent performance. Due to licensing issues I > can't give an actual example of the table, but here is an equivalent > example: > > Field1 and Field2 are both unsigned integers > IndexField1 is an unsigned integer and is the primary key > > select Field1,Field2 from table1 where IndexField1 = 345232; > > We ran this query will different values for IndexField1, sometimes it > would return in around 0.01 seconds, other times it would take as long > as 9 seconds. There was no other load on the database when this was > occurring, and it was specific to certain records (one IndexField1 would > always return around 8 seconds, others would always return around 0.01 > seconds). > > Is there any kind of reasonable explanation for this behavior? Is it > perhaps because of where the records are situated on the hard disk (seek > times)? Is it maybe a caching issue?
How large is the index file? And how large is you key buffer? If your key buffer is too small, you could see variable performance on index-based lookups. Jeremy -- Jeremy D. Zawodny, <[EMAIL PROTECTED]> Technical Yahoo - Yahoo Finance Desk: (408) 349-7878 Fax: (408) 349-5454 Cell: (408) 685-5936 MySQL 3.23.47-max: up 39 days, processed 1,156,755,233 queries (341/sec. avg) --------------------------------------------------------------------- Before posting, please check: http://www.mysql.com/manual.php (the manual) http://lists.mysql.com/ (the list archive) To request this thread, e-mail <[EMAIL PROTECTED]> To unsubscribe, e-mail <[EMAIL PROTECTED]> Trouble unsubscribing? Try: http://lists.mysql.com/php/unsubscribe.php
