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Key: CORE-5965
Type: Bug Bug
Status: Closed Closed
Resolution: Fixed
Priority: Major Major
Assignee: Dmitry Yemanov
Reporter: Haakon Nergaard
Votes: 0
Watchers: 4

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Firebird Core

FB3 Optimiser chooses less efficient plan than FB2.5 optimiser

Created: 16/Nov/18 08:48 PM   Updated: 09/Dec/18 08:59 AM
Component/s: Engine
Affects Version/s: 3.0.4
Fix Version/s: 4.0 Beta 1, 3.0.5

File Attachments: 1. File optimizer_test_setup.sql (2 kB)

Environment: Tested on MacOS and Debian9, both 3.0.4 and 2.5.8
Issue Links:

QA Status: Done successfully

 Description  « Hide
The optimiser in FB3 fails to use an index when there's an extra check in the where clause. The optimiser in FB2.5 can figure it out nicely. Code for creating and populating table in attachment. Example code below:

 * Here's the select. Please test with and without "sysid"
select * from opt_test
--sysid = 1 and
clid = 23 and
cust_type = 1 and
cust_id = 73
order by order_no desc

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