Re: [pysqlite] Erratic behavior under high loads, with APSW code sample

On Mon, Jun 30, 2008 at 11:25 AM, Glenn Maynard <[email protected]> wrote:

> On Mon, Jun 30, 2008 at 06:09:11AM -0500, Frank McIngvale wrote:
> > Hi, I'm having a strange problem with APSW & pysqlite that shows up under
> > higher loads. I've attached two files -- running them like this shows the
> > problem (this occurs under both APIs, I just wrote this sample for APSW):
> >
> > $ rm -f test.db; python raw_apsw.py & python raw_apsw.py & python
> > raw_apsw.py
> > $ python r.py
> >
> > This should show "ROWS=90" at the end. Under Windows (both XP and Vista)
> > this is rock-solid. Under Linux however, the results are erratic, and
> almost
> > always significantly less than 90. I've tried this under both Ubuntu 8.04
> > (linux-2.6.24, apsw 3.3.13, sqlite 3.4.2) and RedHat ES 4 (linux 2-6.9,
> apsw
> > 3.5.9-r1, sqlite 3.5.9). As I understand it, SQLite's auto-transaction
> > feature should keep the INSERTs isolated, but I've also tried this same
> > sample using explicit BEGIN EXCLUSIVE/COMMIT/ROLLBACK, with the same
> > results.
>
> Without adding a conn.commit(), this doesn't add any rows for me at all
> (with sqlite3).  I'm not sure why anything would ever be written without
> not committing.


This is vs. APSW, though. It doesn't have a .commit() and it defaults (my
understanding) to the pysqlite equivalent of 'isolation_level=None', so
SQLite is doing an auto-transaction for each INSERT (in my example). I
definitely am getting data written, just not the whole amount (under POSIX;
Windows is fine).

I can post a pysqlite equivalent sample if that would help. I suspect the
problem lies in SQLite itself, but I wanted to see first if anyone here
could run & replicate the issue on a non-Windows box.

frank




>
> --
> Glenn Maynard
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