As far as I know, SQLite does not support multiple simultaneous writers. I believe you need to be ready to handle SQLITE_BUSY and SQLITE_SCHEMA errors on every call in a multi- threaded application.
SQLITE_BUSY... http://www.sqlite.org/cvstrac/wiki?p=MultiThreading SQLITE_SCHEMA... http://www.sqlite.org/faq.html#q17 The wiki page for multithreaded applications suggests that you use a loop to keep retrying on SQLITE_BUSY but that does not work well, especially since that loop should check for SQLITE_SCHEMA and also have some count to prevent infinite loops. Also backing out of your multiple successful calls to sqlite3_steps() after a single call in a nested loop fails further complicates things, I think. Try use the sqlite3_busy_timeout() or sqlite3_busy_handler() instead. - Kervin RexChan(TP/HK) wrote: > Hi all, > > I meet the problem of multi_thread writing in version 3.2.1. First I create > two threads A and B and each thread has its own db structure. each thread > uses the following SQL commands to do the insert action. > > BEGIN; > . > insert record 200 times > . > . > END; > > Thread A does the insert first and Thread B inserts records during Thread A > is doing the insert action. > > Then the SQLITE_BUSY error is returned to Thread A when doing the "END;" SQL > statement. And Thread B is also returned to SQLITE_BUSY. > And my question is: > > 1. Is it a normal when the error is returned to Thread A when doing the > "END;" SQL statement? > > It seems the Thread A is locking the db although the insert 200 records > action has been done and it wants to do the "END" SQL statement. > > Because I am using ver 2.8.16 and using the same code, it does not happen the > SQLITE_BUSY using its own db structure in each thread. > Do I miss something to do the locking or setting some parameters? thanks! > > Best regards, > Rex >
