Doug Hanks wrote:
Can someone please explain to me, in laymen's terms, what
sqlite3_busy_timeout() is used for?
This routine sets a busy handler that sleeps for a while when a
table is locked. The handler will sleep multiple times until at
least "ms" milliseconds of sleeping have been done. After "ms"
milliseconds of sleeping, the handler returns 0 which causes
sqlite3_exec() to return SQLITE_BUSY.
Perhaps an example with an explaination is in order?
Suppose you are trying to perform a select, but there's an update
currently in progress. Without sqlite3_busy_timeout or explicit busy
handler, your operation will fail immediately with SQLITE_BUSY. But if
you set up sqlite3_busy_timeout, SQLite will automatically retry your
operation several times before erroring out. Hopefully the writing
transaction completes before the timeout has expired, and your select is
allowed to proceed.
Igor Tandetnik
