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Sqlite vacuum update#
Sqlite vacuum manual#

If you aren't using explicit BEGIN/ COMMIT, you're still creating transactions, one per SQL statement. It takes an unfinalized transaction to do that. It's unnecessary because VACUUM will still run if there's simply an idle connection to the DB. If you literally mean that you sqlite3_close() the conn after each query, it's both unnecessary from the point of view of this question and it'll also slow SQLite down considerably. even though I try to close all readers right away. Once a month or once a year might suffice.

Sqlite vacuum manual#

In such cases, you'd schedule the VACUUM for manual downtime, such as during upgrades.įrequent VACUUM isn't super useful in a lot of apps anyway. You might not be allowed to lock the whole system up for arbitrarily long times. If you can never predict a time when the DB will be idle, you might not want to VACUUM automatically at all, since it can take a long time, and such always-in-use apps generally have tight service levels. in an always-running app serving a single regional organization App startup time, before any of these other threads start.

App shutdown time, just before the last conn is closed.

VACUUM is best run at a time when you can predict that the DB will be idle. I continuously get an error when I run VACUUM that some statements are still running. So main question is: Is it safe to do VACUUM in a new connection, and will the DB end up properly defraged? What will happen with the other running statements? Will they fail? They seem to finish fine as far as I can tell. I understand that the other open transactions are gone. I decided to open a new connection, and run just the VACUUM command on that. VACUUM (but not VACUUM INTO) is a write operation and so if another database connection is holding a lock that prevents writes, then the VACUUM will fail." Unfinalized SQL statements typically hold a read transaction open, so the VACUUM might fail if there are unfinalized SQL statements on the same connection. "A VACUUM will fail if there is an open transaction on the database connection that is attempting to run the VACUUM. I have no way of telling which statements those are, app is multi-threaded, even though I try to close all readers right away.

Sqlite vacuum update#

UPDATE 1) is not relevant - looks like I'm facing some cascade delete problems (I've described them in this topic).I continuously get an error when I run VACUUM that some statements are still running. Shouldn't it be real number of affected rows? That is not what I expected? Shouldn't it be ~23.6 mb as the original database was? !NOT RELEVANT FOR NOW!Ģ) For some reason rowsAffected equals 0 even if I use two cmd.ExecuteNonQuery() one after another - first one slightly shrinks database from 47.3 mb to 45.7 mb, second one leaves it's size unchanged).

After VACUUM command second database becomes 45.7 mb. Var rowsAffected = cmd.ExecuteNonQuery() ġ) I have sample.db (23.6 mb) and sample_big.db (47.3 mb) which contains the same data (second database is a copy of first database where all objects were deleted and added again). Using (SQLiteCommand cmd = conn.CreateCommand()) Code: Select all using (SQLiteConnection conn = new SQLiteConnection(mySQLiteConnectionStringBuilder.ToString()))