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Key: CORE-1381
Type: New Feature New Feature
Status: Closed Closed
Resolution: Fixed
Priority: Major Major
Assignee: Vlad Khorsun
Reporter: Vlad Khorsun
Votes: 0
Watchers: 1

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Firebird Core

Allow Firebird to bypass filesystem cache for database files (on Windows)

Created: 25/Jul/07 01:57 PM   Updated: 26/Sep/07 03:13 AM
Component/s: Engine
Affects Version/s: None
Fix Version/s: 2.1 Beta 2

Issue Links:

 Description  « Hide
Firebird may be configured to use large own page buffers cache. In such case filesystem cache will duplicate Firebird's one and give no or small benefit on file reads wasting memory for double caching. It still helps on file writes but only if Forced Writes setting is OFF which is not recommended in most cases.

Proposition is to allow Firebird to not use filesystem cache to free more memory for another operations such as sorting and\or caching of another database etc

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Sean Leyne added a comment - 25/Jul/07 02:15 PM
Aren't we trying to get too smart.

Afterall, if the OS wants to cache the file (for read accesses) why would we care. The OS will release the file cache as required, when processes request the memory.

Vlad Khorsun added a comment - 25/Jul/07 02:27 PM
Sean, this was discussed in fb-devel half year ago.
If you want to continue discussion, please, do it in fb-devel to not lose already pointed arguments

Dmitry Yemanov added a comment - 25/Jul/07 02:28 PM
Often, when Windows tries to cache a big file, it moves the FB page cache to the swap, thus causing *a lot* of unnecessary paging. In my practice, if the FB page cache size is set to more than 80% of the available RAM, you're getting big troubles. Of course, I speak about SuperServer only (the OS file cache is *a must* for Classic).

Pavel Cisar added a comment - 09/Aug/07 05:23 AM
This feature was implemented for Windows only. We'll open another related ticket if we'll implement it for other platforms as well.

Vlad Khorsun added a comment - 26/Sep/07 03:13 AM
CORE-1480 is for Posix platforms implementation