| Subject | Re: [firebird-support] database page size? |
|---|---|
| Author | Ann Harrison |
| Post date | 2011-06-16T18:21:36Z |
On Thu, Jun 16, 2011 at 2:09 PM, heineferreira <heineferreira@...> wrote:
lots of rows or large blobs. Obviously, if you've got blobs that are
larger than a page, you're going to read two or more pages per blob.
Less obviously, larger index pages lead to shallower indexes. Each
page at an upper level can point to a number of lower level pages that
is determined by a combination of the length of the key and the size
of the page. Shallow indexes are more efficient.
On the other hand, if you use a large page size and realize that lots
of pages are partially filled, you're wasting both disk and cache
space.
Generally, 4Kb is a pretty good size. If you notice that you have an
index with more than three levels, increase the page size by backing
up and restoring the database with gbak.
Good luck,
Ann
>Larger page sizes are important when you're dealing with tables with
> I was experimenting with FlameRobin and Firebird 2.5 and saw that there are a wide variety of page sizes. I see Flamerobin defaults to 4k page size. How do I know what page size to select when creating a new database?
lots of rows or large blobs. Obviously, if you've got blobs that are
larger than a page, you're going to read two or more pages per blob.
Less obviously, larger index pages lead to shallower indexes. Each
page at an upper level can point to a number of lower level pages that
is determined by a combination of the length of the key and the size
of the page. Shallow indexes are more efficient.
On the other hand, if you use a large page size and realize that lots
of pages are partially filled, you're wasting both disk and cache
space.
Generally, 4Kb is a pretty good size. If you notice that you have an
index with more than three levels, increase the page size by backing
up and restoring the database with gbak.
Good luck,
Ann