[ https://issues.apache.org/jira/browse/DERBY-1699?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]
Mamta A. Satoor updated DERBY-1699: ----------------------------------- Urgency: Normal Labels: derby_triage10_11 (was: ) > Save optimizer costs in saved obejcts rather than as compiled byte code, > reduces memory usage and generated class size. > ----------------------------------------------------------------------------------------------------------------------- > > Key: DERBY-1699 > URL: https://issues.apache.org/jira/browse/DERBY-1699 > Project: Derby > Issue Type: Improvement > Components: SQL > Reporter: Daniel John Debrunner > Labels: derby_triage10_11 > > A UNION node will generate byte code to call this method: > NoPutResultSet getUnionResultSet(NoPutResultSet source1, > NoPutResultSet source2, > Activation activation, > int resultSetNumber, > double optimizerEstimatedRowCount, > double optimizerEstimatedCost, > GeneratedMethod closeCleanup) > The optimizer costs being passed in are rarely used, in some cases they are > used as estimates for sizing items. > They are also used if the plan is displayed, to show the costs. > It's possible that the cost estimates could be saved in the saved objects > structure of the plan and be available by > result set number. E.g. .store a Hashtable in the saved objects with a key of > "costEstimates", the hashtable would have a key of resultSetNumber and value > of a StoreCostResult. This would also be a one time storage at compile time, > rather than the current code which incurs a both a cpu and memory cost at > runtime for each ResultSet and hence each active query. > This would apply to any node that takes an optimizer cost. > This has been split out from DERBY-766 -- 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