Following is a list of performance enhancements introduced in version 12.0.1 for which there are no user-visible changes other than performance improvement.
Immediate text indexes Performance of immediate text index maintenance has improved. The performance improvement you observe will depend on the workload and on the document and text index content. Text indexes indexing long documents benefit the most from this improvement.
Physical deletes are deferred to the cleaner To improve transaction performance, rows are not physically deleted at commit time. Instead, they are left marked as logically deleted with the actual removal being deferred to the cleaner. To prevent excessive database growth, the cleaning schedule has been made more aggressive. See sa_clean_database system procedure.
Bypassable queries may now have computed columns defined for the table in the FROM clause One of the conditions for a query to be considered for bypassing the optimizer was to have no computed columns defined for the base table referenced in the FROM clause. This restriction has been removed starting with SA 12.0.1. The common subexpression elimination process using computed columns is done for bypassed queries similar to the queries using the SQL Anywhere optimizer.
Bypass queries now possible when base table contains computed columns Previously, a query could not qualify as a bypass query if the base table referenced in the FROM clause had computed columns. This restriction has been removed. See Eligibility to skip query processing phases.
Enhancements to the optimizer's use of indexes Several enhancements have been made to the indexing capabilities of SQL Anywhere, including improvements to optimize queries that use partial index scans and multiple index scans that use the same index.
IS NOT NULL search condition The optimizer can now use an index to evaluate the IS NOT NULL search condition. See Query predicates.
Discuss this page in DocCommentXchange.
|Copyright © 2014, SAP AG or an SAP affiliate company. - SAP Sybase SQL Anywhere 16.0|