Re: Transaction commit speed

Sam Dave wrote:

Hi,

Are transaction commits always fast (almost instantaneous) operations compared to the read or write operations within it? Is it possible for say an mdb_cursor_get or mdb_put to be faster than a subsequent mdb_txn_commit, and if so under what circumstances can that happen?

This is relevant info for UI applications showing a progress indicator. If an mdb_txn_commit is always fast, we can rely on the _get/_put count to calculate the percentage.

Generally no, a txn_commit should take time proportional to the number of pages that were dirtied in the transaction. And that number depends on the number of puts/dels that were performed in the transaction.

gets don't dirty any pages, so they are irrelevant for commit speed.