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Key: CORE-1598
Type: Improvement Improvement
Status: Closed Closed
Resolution: Fixed
Priority: Minor Minor
Assignee: Dmitry Yemanov
Reporter: Dmitry Yemanov
Votes: 0
Watchers: 0
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Firebird Core

Optimize data retrieval for tables when no fields are accessed

Created: 16/Nov/07 01:31 AM   Updated: 12/Nov/09 03:56 PM
Component/s: Engine
Affects Version/s: None
Fix Version/s: 2.5 Alpha 1

Time Tracking:
Not Specified

Target: 2.5.0


 Description  « Hide
There are some queries (e.g. select count(*) from <tab>) that don't access any table fields (explicitly or implicitly). In this case, only the record header could be processed and the record data decompression could be avoided. Simple tests against the prototype implementation show about 50-80% of performance improvement (when appropriate data pages are cached).

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