[EMAIL PROTECTED] uttered: > I have 300K ..and the blob .. separate database.. CD > media, the performance .. 2 minutes sometime > to retreive the result
>>>[Is the cdrom noisy at this point? Making intermittent whirring noises? Some cdroms are noisier than others.] * I tried different discs in a few machines, including vmware > > the blob database... within 1.5sec or less from the CD. ... LED on the CD rom blinking only occasionally, not > constantly like when I copy a file. >>>[If the LED only lights when data is being transferred, then what you're seeing is the latency of individual reads. This is not surprising, as cdroms have horrendously slow seek times. When copying regular files, the file itself is likely to be contiguous on the CD, therefore no seeks are required. A SQLite database, on the other hand, has tree structure scattered around the file. Seeks are common and slow. Vacuuming, as DRH suggests, will reduce the seeks as tables will be more contiguous.] * The database is only populated once , I posted search fields into one database which performs badly, and posted the text as blobs which performs well even on CD. I also have a system in place where I can post the blobs as either sqlite or zip or raw files and I am happy with that performance >>>[The OS should shield you from this. One way to possibly increase performance is to the prime the OS cache by reading in the CD file in it's entirety (just read the raw file). Hopefully, the file should fit in the OS's memory cache, and subsequent SQLite reads can be satisfied from the OS cache, though that may be unfeasable with a database of your size.] * The records db is 20MB indexed, and the blob is 140MB. >>>[You might also want to increase the database page size when creating the database in the first place, as you'll have less actual pages and hence less seeks for a given database size.] * I am using a Delphi wrapper, I need to investigate further. [* sorry first time with outlook I have to set it up later properly] -- No virus found in this outgoing message. Checked by AVG Free Edition. Version: 7.1.394 / Virus Database: 268.14.6/535 - Release Date: 15/11/2006 ----------------------------------------------------------------------------- To unsubscribe, send email to [EMAIL PROTECTED] -----------------------------------------------------------------------------
