Hi everyone,
I have an interesting locking problem that I'm wondering if someone can help
with some insight.
I have a master database with some metadata, and several sub-databases to store
logging events. I have one reader object and one writer object that attach to
the sub-databases and encapsulate the read/write operations respectively.
I've found a very unexpected locking behavior with the attached databases and
exclusive transactions. One of my unit tests does the following:
Begin EXCLUSIVE TRANSACTION;
insert several rows of data;
Commit transaction;
Prepare query statement;
Iterate through one or more rows;
Reset statement;
Attempt to begin transaction; <--- SQLITE_BUSY!!!!
Would like to write more here, but can't unless I close/open the connection;
I can't seem to figure out any reason why I can't create a new exclusive
transaction here, and I feel it must have to do with the fact that I have
attached to sub-databases (possibly the same sub-database) with my
reader/writer objects. This is single threaded and only database connection
(with attach/detach logic).
I have verified that all statements prepared by the connection are properly
reset - this is handled by my C++ wrappers, and any errors will throw an
exception. I even iterated through all of the current statements with the
following code immediately before my transaction failure, with no results:
sqlite3_stmt *stmt = NULL;
while ((stmt = sqlite3_next_stmt(db, stmt)) != NULL)
{
if (sqlite3_stmt_busy(stmt))
{
const char* sql = sqlite3_sql(stmt);
std::cout << sql << "\r\n";
}
}
Can anyone think of a reason why attached databases would prevent entering a
second transaction? BTW, it doesn't seem to work with immediate transactions
either. If I remove the query, everything works fine.
Thanks!
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