Thankyou, spot on the mark :) Now we've got it blazing fast, time to move backwards towards a reasonable mix of safety and speed.
[EMAIL PROTECTED] wrote: > Bill KING <[EMAIL PROTECTED]> wrote: > >> Okay, i've got PRAGMA synchronous = OFF and PRAGMA temp_store = memory >> but i'm still seeing the system locking up and waiting for write when >> writing to sd-cards >> > > PRAGMA synchronous=OFF prevents SQLite from calling fsync() > and fdatasync(). On most filesystems, that means all write() > requests are queued by the OS and the data is not actually > written out to the device until some time after the write() > call returns - sometimes much later. But on some filesystems, > calls to write() are synchronous. That is to say, write() > does not return until the information has reached hard media. > > On Linux, whether or not a write() is synchronous is controled > (in at least one way) by the "sync" option to the mount command > when the filesystem is mounted. > > It is not uncommon for write() to be synchronous on removable > media. I know that on my SuSE Linux laptop (on which I am typing > this message) if I plug in a USB thumb drive, it automounts > synchronous and write performance is abysmal. I have to go > root, unmount the thumb drive, then remount it for asynchronous > writes. Then it is blazing fast. You just have to be careful > to unmount it before pulling it out of the USB slot.... > -- > D. Richard Hipp <[EMAIL PROTECTED]> > > > ----------------------------------------------------------------------------- > To unsubscribe, send email to [EMAIL PROTECTED] > ----------------------------------------------------------------------------- > > > -- Bill King, Software Engineer Trolltech, Brisbane Technology Park 26 Brandl St, Eight Mile Plains, QLD, Australia, 4113 Tel + 61 7 3219 9906 (x137) Fax + 61 7 3219 9938 mobile: 0423 532 733 ----------------------------------------------------------------------------- To unsubscribe, send email to [EMAIL PROTECTED] -----------------------------------------------------------------------------
