Improve performance of String literals in statements
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Key: DERBY-909
URL: http://issues.apache.org/jira/browse/DERBY-909
Project: Derby
Type: Improvement
Components: Newcomer, SQL
Reporter: Daniel John Debrunner
Priority: Minor
String literals (constants) go through this process currently
Create String object from within parser
Serialized String into generated class file as UTF-8 (taking up two constant
pool entries)
Unserialize and intern String from generated class at class load time
The serialize into the class file and un-serialize can be avoided by saving
the String in the saved object pool (see CompilerContext)
This would benefit the common pattern we see in SQL scripts that load data like:
insert into customer values (1, 'Fred', 'Flintstone');
insert into customer values (2, 'Wilma'', 'Flintstone');
etc.
etc.
Note these are poor performing in Derby compared to other databases.
It would also be a step on the way to having a single compiled plan for such
statements that don't use parameter markers.
Most likely the performance benefit with inserts will be small until DERBY-888
is fixed, because with inserts the sync of the allocated pages dominates the
cost.
Possible newcomer task with guideance.
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