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https://issues.apache.org/jira/browse/DERBY-4327?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13758991#comment-13758991
] Dag H. Wanvik edited comment on DERBY-4327 at 9/5/13 11:28 AM: --------------------------------------------------------------- Some links: https://www.simple-talk.com/sql/performance/join-reordering-and-bushy-plans/ http://www.google.co.uk/url?sa=t&rct=j&q=&esrc=s&source=web&cd=1&ved=0CDwQFjAA&url=http%3A%2F%2Fciteseerx.ist.psu.edu%2Fviewdoc%2Fdownload%3Fdoi%3D10.1.1.56.6379%26rep%3Drep1%26type%3Dpdf&ei=3GUoUtbTN8uQ0QWh0oDYAw&usg=AFQjCNFme8BiQI59ZnxP68M6cnY0Pzr_cA&bvm=bv.51773540,d.d2k&cad=rja was (Author: dagw): http://www.google.co.uk/url?sa=t&rct=j&q=&esrc=s&source=web&cd=1&ved=0CDwQFjAA&url=http%3A%2F%2Fciteseerx.ist.psu.edu%2Fviewdoc%2Fdownload%3Fdoi%3D10.1.1.56.6379%26rep%3Drep1%26type%3Dpdf&ei=3GUoUtbTN8uQ0QWh0oDYAw&usg=AFQjCNFme8BiQI59ZnxP68M6cnY0Pzr_cA&bvm=bv.51773540,d.d2k&cad=rja > Implement optimizer support for bushy trees. > -------------------------------------------- > > Key: DERBY-4327 > URL: https://issues.apache.org/jira/browse/DERBY-4327 > Project: Derby > Issue Type: Improvement > Components: SQL > Reporter: Rick Hillegas > Labels: derby_triage10_10 > > Currently, the optimizer only considers left-deep trees. For queries > involving many tables, the best plan may be bushy. In this email thread, a > user notes poor performance by Derby on queries involving 5 or more tables: > http://www.nabble.com/Slow-performance-on-5-or-more-joins-in-a-star-schema-tt24708686.html -- This message is automatically generated by JIRA. If you think it was sent incorrectly, please contact your JIRA administrators For more information on JIRA, see: http://www.atlassian.com/software/jira
