[jira] Resolved: (DERBY-3136) Cut down on object creations in LIKE clause implementation of territory based characters.

["Mamta A. Satoor (JIRA)" <ji...@apache.org>]

     [ https://issues.apache.org/jira/browse/DERBY-3136?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Mamta A. Satoor resolved DERBY-3136.
------------------------------------

       Resolution: Fixed
    Fix Version/s: 10.4.0.0
                   10.3.1.5

Merged changed from trunk into 10.3 codeline (revision 588148).

> Cut down on object creations in LIKE clause implementation of territory based characters.
> -----------------------------------------------------------------------------------------
>
>                 Key: DERBY-3136
>                 URL: https://issues.apache.org/jira/browse/DERBY-3136
>             Project: Derby
>          Issue Type: Improvement
>          Components: SQL
>    Affects Versions: 10.3.1.5, 10.4.0.0
>            Reporter: Mamta A. Satoor
>            Assignee: Mamta A. Satoor
>             Fix For: 10.3.1.5, 10.4.0.0
>
>
> The LIKE clause for territory based characters was implemented correctly based on SQL standards in DERBY-2967 but the object (String and CollationElementIterator) creations introduced in DERBY-2967 can be cut down by following Knut's simple solution. I am copying that solution from DERBY-2967. We should implement that solution to improve the performance of LIKE for territory based characters.
> **********copied from DERBY-2967**********************************************************
> Another simple way to cut down the string allocations... I think you could express iapi.types.Like:checkEquality() like this: 
>     if (val[vLoc] == pat[pLoc]) { 
>         // same character, so two strings consisting of this 
>         // single character must be equal regardless of territory 
>         return true; 
>     } else if (collator == null) { 
>         // not same character, must be unequal in UCS_BASIC 
>         return false; 
>     } 
>     String s1 = new String(val, vLoc, 1); 
>     String s1 = new String(pat, pLoc, 1); 
>     return collator.compare(s1, s2) == 0; 
> This would only allocate new objects if the characters are not equal. 
> ****************************************************************************************** 

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