If I remove the locking_mode=exclusive, I don't get those errors.
I'd appreciate any advice on how I can get the best performance using multiple
threads in my application, given that:
1. I need maximum performance. That is also why I need multiple threads
2. All threads need to write to the same db
3. No other application needs access to the db
4. I don't care about durability, just fast insert times since reads are much
less frequent.
Ray
________________________________
From: Rizzuto, Raymond
Sent: Wednesday, July 08, 2009 3:27 PM
To: 'sqlite-users@sqlite.org'
Subject: multi-thread access to a db
I have an application where I have 7 threads. Each thread opens its own db
connection object, but the connections are to the same db. I am seeing
sporadic insert failures when a thread attempts to insert into the db.
sqlite3_errmsg returns this message:
database is locked
I am using sqlite3 version 3.6.1. I use the following two pragmas to get the
best insert performance (the db is used exclusively by this application, and I
don't need to have the DB recover after an os crash or power fail):
sqlite3_exec(result->db, "pragma synchronous=off;", 0, 0, &zErrMsg);
sqlite3_exec(result->db, "pragma locking_mode=exclusive;", 0, 0,
&zErrMsg);
I am using threading mode "multi-thread".
Does mode=exclusive mean that the first thread that opens and writes to the db
locks out all other threads?
Ray
________________________________
Ray Rizzuto
raymond.rizz...@sig.com
Susquehanna International Group
(610)747-2336 (W)
(215)776-3780 (C)
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