[Geotools-devel] [JIRA] (GEOT-5186) Add support for DB2 selectivity clause

[Chrstian Mueller (JIRA)]

Title: Message Title

Chrstian Mueller created an issue   GeoTools / GEOT-5186 Add support for DB2 selectivity clause Issue Type: Improvement Affects Versions: 14-M1, 13.2 Assignee: Chrstian Mueller Components: jdbc-db2 plugin Created: 08/Aug/15 12:38 PM Fix Versions: 14-beta, 13.3 Priority: High Reporter: Chrstian Mueller DB2 uses a cost based query optimizer based on distribution statistics of the actual data. Unfortunately there is no distribution statistics for geometry attributes. As a consequence, the optimizer is not able to deal with spatial indices correctly. The full description is here: http://www.ibm.com/developerworks/data/library/techarticle/dm-0510stolze/ It is possible to give a hint to the optimizer. SELECT ... FROM <user_table> WHERE ST_Intersects(<indexed_shape_column>, ...) = 1 should be SELECT ... FROM <user_table> WHERE ST_Intersects(<indexed_shape_column>, ...) = 1 SELECTIVITY 0.000001 The idea is to add a param USESELECTIVITY to the class DB2NGDataStoreFactory which defaults to FALSE. If the param is TRUE, the selectivity clause will be used. Add Comment   This message was sent by Atlassian JIRA (v6.5-OD-08-001#65007-sha1:1fc9846)

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