SQLite databases are protected like a big reader-writer lock: there is no way read while you are writing. "BEGIN IMMEDIATE" simply changes when it takes the write lock, and won't affect this.
On 9/15/06, Liam Healy <[EMAIL PROTECTED]> wrote:
I have a database that has one writer which runs once a day, and potentially many readers running whenever someone wants some information. I am trying to understand concurrency in sqlite3 so that I can have the writer run each day, regardless of whether a reader is already running or a reader starts up after the writer is running. I am referring to the documentation http://www.sqlite.org/lang_transaction.html and http://sqlite.org/lockingv3.html but I can't quite figure out how to do this. I understand from lang_transaction that if the writer starts with BEGIN IMMEDIATE and ends with END then it will be possible for readers to read the database while the writer is updating it: "After a BEGIN IMMEDIATE, you are guaranteed that no other thread or process will be able to write to the database or do a BEGIN IMMEDIATE or BEGIN EXCLUSIVE. Other processes can continue to read from the database, however." Yet when I try to start up the reader and open the database while the writer is running, I get SQLITE_BUSY. Any advice on how to have the reader and writer work without interfering with each other (the reader is only trying to read old data, not what the writer is inserting) would be appreciated. Thank you. Liam ----------------------------------------------------------------------------- To unsubscribe, send email to [EMAIL PROTECTED] -----------------------------------------------------------------------------
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