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Key: CORE-4183
Type: Improvement Improvement
Status: Open Open
Priority: Major Major
Assignee: Unassigned
Reporter: Pavel Zotov
Votes: 0
Watchers: 1
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Firebird Core

Provide ability to log via TRACE usage of preliminarily selected indexes in queries

Created: 19/Aug/13 05:54 PM   Updated: 20/Aug/13 03:00 AM
Component/s: TRACEMGR
Affects Version/s: 3.0 Alpha 1
Fix Version/s: None


 Description  « Hide
Currently we can not be sure whether some index (say, MY_INDEX_A) is ever in use or not.
All indexes decrease performance (more or less) of inserts and updates and also they all will be handled by GC that can take significant time.
So the rule of thumb is simple: do not create index "just in case". But in real prod systems this rule often is violated and one can hard to find where some index 'X' is used.

It will be useful if trace config will contain something like 'INDEX_FILTER <my_index_name1 | my_index_name2 | %my_pattern%>' for such logging.

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Sean Leyne added a comment - 19/Aug/13 08:26 PM
Why did you add the word "preliminary" to the case description?

In what context do you mean "preliminary"?

Pavel Zotov added a comment - 20/Aug/13 03:00 AM
When there is a doubt about whether some index is ever selected by FB optimizer or not - it will be good idea to add it's name to trace config list of arguments for special (new) parameter.

PS. Sorry, my english is bad. If this word - 'preliminary' - isn`t properly used please remove it from the header of ticked.