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Re: SQLite Clarification

On Monday 31 July 2006 16:05, Clif Flynt wrote:
> > The database file is only locked for the duration
> > of the write operation - not while the database is open.  A write
> > normally takes a few milliseconds, then the lock goes away.

The issue here is that you may need write to have priority since there is 
potentially a backlog building in the kernel. If the backlog gets too big you 
will get a panic. The write operation has to be fast.

But suppose there are readers. Does the write block or fail? More of a 
curiosity to me.

> > Why is 256 bytes of data for each 1MiB of database a problem?
> > Is memory so short and databases so large that this might cause
> > a problem?

Database could be huge. A paranoid admin could easily get gigabytes of data in 
a short time. Or maybe someone that wrote a rule that captures too much data 
could run into a problem.

> > If it is, then increase the page size from the default 1K.
> > The actually usage is 2 bits per page of data.  So if pages
> > are 32KiB bytes instead of 1KiB, a 1MiB database only needs
> > 8 bytes of storage for the bitmap.

This is good to know. That would probably help.


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