Vis Naicker uttered:
[EMAIL PROTECTED] uttered:
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 blobs are most likely largely contiguous.
[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.
So it may be feasible to prime your machine cache with the records db. Not
neccessary for the blob database if it's working fine.
[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.
Execute "PRAGMA page_size=<size>;" to set the page size, BEFORE you put
any data in the database. Try, off the bat, a page size of 16384.
[* sorry first time with outlook I have to set it up later properly]
You have no hope of setting it up properly:)
--
/"\
\ / ASCII RIBBON CAMPAIGN - AGAINST HTML MAIL
X - AGAINST MS ATTACHMENTS
/ \
-----------------------------------------------------------------------------
To unsubscribe, send email to [EMAIL PROTECTED]
-----------------------------------------------------------------------------
