Subject Re: [ib-support] Re: Mixing DB page sizes
Author Helen Borrie
At 11:58 AM 20-12-01 +1100, you wrote:
>Further question ....
>Why would you want to ?
>I was under the impression that the page size should match the OS memory
>page size ?
>And therefore should be the same on the same box ?

Nope. Page size is determined by the needs of the data and your performance requirements. Here are some notes extracted from a forthcoming manual:

Changing the page size can improve performance in the following conditions:

q Storing and retrieving blob data is most efficient when the entire blob fits on a single database page. If an application stores many Blobs exceeding 4KB, a larger page size reduces the time for accessing blob data.
q Firebird performs better if rows do not span pages. Consider increasing the page size if a database contains any tables with long rows of data.
q If a database contains any large indexes, a larger database page size reduces the number of levels in the index tree. The smaller the depth of indexes, the faster they can be traversed. Consider increasing the page size if index depth is greater than three on any frequently used index.
q Reducing the page size may be appropriate if most transactions involve only a few rows of data, because the volume of data needing to be passed back and forth is lower and less memory is used by the disk cache.


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