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SQLite Clarification



On Mon, Jul 31, 2006 at 01:54:30PM -0400, Steve Grubb wrote:
> On Monday 31 July 2006 13:14, Clif Flynt wrote:
>
> >   My current report generator builds an SQLite database on the fly from
> > the flat ASCII logs.
> 
> Seems like this would be ideal to marry to the realtime audit event interface. 
> You would set log_format = nolog, dispatcher = /sbin/your-dispatcher, and 
> disp_qos = lossless to keep the audit system from writing to disk, send 
> events to a program, and use blocking comminucation to do it.
> 
> >   I'm using SQLite instead of mySQL or Postgres because it it's fast,
> > mature and robust and doesn't  require any database server (or dbadmin)
> > to run it.
> 
> I've been looking at using it too. I read some issues that made me wonder if 
> it was really suitable:
> 
> http://www.sqlite.org/whentouse.html
> 
> At the bottom it mentions that if something has the database open for read, 
> then writing is blocked. And the issue about the journal using 256 bytes for 
> event MB of data made me wonder also.

  My other reason for using SQLite is that I'm working with the
developer.  I forwarded your concerns to Richard Hipp, and received
this response:

> 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.
> 
> 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?
> 
> 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.
> 
> --
> D. Richard Hipp   <drh hwaci com>

  Clif

-- 
.... Clif Flynt ... http://www.cflynt.com ... clif cflynt com ...
.. Tcl/Tk: A Developer's Guide (2nd edition) - Morgan Kauffman ..
..13th Annual Tcl/Tk Conference:  Oct 9-13, 2006,  Chicago, IL ..
.............  http://www.tcl.tk/community/tcl2006/  ............



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