On 3/27/2013 12:16 PM, Bergquist, Brett wrote:
Some background.I have a customer that is using an earlier release of our system that has Derby 10.8.2.1 installed. Because of issues like https://issues.apache.org/jira/browse/DERBY-5680, it has been running with the indexStat daemon disabled. We are going to have a new release soon and it will be installing Derby 10.9.1.0 with the indexStat daemon enabled. I recently got a copy of the customer's database (132Gb) and ran into a very long query. I manually ran SYS_UTIL.SYSCS_UPDATE_STATISTICS on all of the tables in the query to ensure that the statistics are up to date. ...
when I look at bad query plans i usually look for estimated row counts vs actual to see where the optimizer made some bad assumptions. The plan you posted has a bunch of 0's. So maybe you aren't gathering the
plan with all options enabled? If optimizer actually thinks there are 0 rows in your 62 million row table that would be a problem.
