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Shuxiong Ye commented on PHOENIX-1987: -------------------------------------- Hi [~jamestaylor], Patch [1] adds tests in QueryCompilerTest to check optimization about ORDER BY. Please help me to review it. I have a question in my previous comment. Please give me some hints about it. : ) [1] 0001-PHOENIX-1987-fixing-getKeyFormationTraversalIndex-in-SIGN-function.patch > SIGN built-in function should be order preserving > ------------------------------------------------- > > Key: PHOENIX-1987 > URL: https://issues.apache.org/jira/browse/PHOENIX-1987 > Project: Phoenix > Issue Type: Sub-task > Reporter: James Taylor > Assignee: Shuxiong Ye > Fix For: 5.0.0, 4.5.0, 4.4.1 > > Attachments: > 0001-PHOENIX-1987-SIGN-built-in-function-should-be-order_v2.patch, > 0001-PHOENIX-1987-fixing-getKeyFormationTraversalIndex-in-SIGN-function.patch > > > The SIGN built-in function preserves the order of its input. This needs to be > explicitly implemented in SignFunction by implementing the following method: > {code} > public OrderPreserving preservesOrder() { > return OrderPreserving.YES; > } > {code} > This will allow certain optimizations reducing the amount of memory and/or > buffering that is required if SIGN is used in a GROUP BY or ORDER BY clause. -- This message was sent by Atlassian JIRA (v6.3.4#6332)