FB 1.5 için bazı değerler şöyle
Maximum Page Size : 16,384 bytes
(Burda diğer seçenekler 1024 , 2048, 4096 (default) , 8192)
Bunlardan birni seçmek lazım
[Any other numbers will be resolved back to the next lowest number in this range. For example if you specify 3072, FB will create a database with a page size of 2048])
Maximum Cache Buffers: 65,536 pages
Practical limits depend on available ram. The total size
(cache pages * page_size on Superserver;
cache pages * page_size * no. of concurrent users on classic server)
should never be more than half of the available ram.
Consider 10000 pages as a practical limit and tweak backward or forward from there as performance dictates.
The Database Cache
Database cache is a chunk of memory reserved for each db running on the server. Its purpose is to cache all of the database pages (also called buffers) that have been most recently used. ... Default setting, which constitutes a number of blocks of memory, or page buffers, each the size of one db page, is set in the server's conf. file;
The parameter is DefaultDbCachePages in firebird.conf.
The number of cache buffers required is approximate. It needs to be large enough to cater for the page requirements of databases but not so large as to consume memory that is needed for other operationas. Up to a point, the more activity that can be handled in cache, the better the overall performance. The axion "Database servers love RAM" is true for Firebird. But FB uses RAM for other activities that are at least as important as caching. Transaction inventory and index bitmaps are maintained in RAM and, from v1.5, sorting and merging are done in memory, if it is available.
It is important to realize that every system has a critical point where too-large cache configuration will consume more memory resources than the system can "spare". Beyond this point, enlarging the cache will cause performance to degrade
Limits and Default
The min cache size is 50 pages. Ther is no maximum, as long as the allocation in total does not exceed the RAM available.
Default cache allocation is
- Superserver
For each runnig dataabase,2048 pages. All users share this common cache pool.
As an indication of how resources can be consumed, a single database running at the default settings for PAGE_SIZE(4k- 4096b) and defauldDbCachePages(2k) requires 8 mb memory. Two databases running with the same settings require 16 mb, and so on. Default caches usage is calculated:
PAGE_SIZE * defauldDbCachePages * number of databases - Classic Server: Per Client attachment, 75 cache pages. Each attachment is allocated its own cache. The amount of memory required is the total of the cache requirements of all client attachments to each database. Cache usage is calculated by
PAGE_SIZE * defauldDbCachePages * number of attachments
Sort la ilgili açıklamalar şöyle;
Temporary Sort Space
Queries with ORDER BY or GROUP BY clauses " park" the intermediate sets for sorting operations in temporary storage space. It is recommended that you have storage available that is approximately 2,5 times the size of the largest table you will sort. FB 1.5 and higher versions can configure sort space in RAM; all versions needed to have temporary disk space to use for these operations.
Sort Memory
v1.5 and higher set the default block size of sort memory at 1 mb. This is the size of each chunk of RAM that the server will allocate, up to a default max of 64 mb on SuperServer and 8 Mb of Classic Server. Both of these values can be reconfigured by means of the conf. parameters SortMemBlockSize and SortMemUpperLimit,.
Classic server için bunu kastırmamak tavsiye ediliyor.
Sort Space on Disk
TMP or TEMP on Windows.
You can configure sort space in two ways.
1 Set up directory location using the environment variable FIREBIRD_TMP
2 Configure directories in firebird.conf for v1.5 and higher.
