Hi, For the past half year we’ve been receiving reports from users who had restored their SQLite-based databases from a Time Machine backup. Afterwards, they would receive "database disk image is malformed” errors. The app also backs up the user’s data “manually” to a ZIP file every week; those backups seem to be working fine. We also haven’t received reports from other backup tools causing issues. I have also suspected a bug in Time Machine, but it is striking that the issues did seem to start occurring after an update to the app (luckily, in fact, with the same update that also introduced the “manual” backups).
Changes that we made to our setup in the update that coincided with the errors occurring: - Upgraded SQLite from 3.21 to 3.24 (we have since reverted to 3.23.1 in another update; no improvement). - Used memory mapping for read accesses via “PRAGMA mmap_size = 1073741824;” (we have since reverted to “PRAGMA mmap_size = 0;” after reading http://sqlite.1065341.n5.nabble.com/Re-Database-corruption-and-PRAGMA-fullfsync-on-macOS-td95366.html <http://sqlite.1065341.n5.nabble.com/Re-Database-corruption-and-PRAGMA-fullfsync-on-macOS-td95366.html>; no improvement). - Using a secondary database via [ATTACH DATABASE](https://www.sqlite.org/lang_attach.html <https://www.sqlite.org/lang_attach.html>) (although this also seems to occur for users without such a database). At this point, I am at a loss, especially given that SQLite should be fairly robust against database corruption. While our app is running in the background all the time, it is not very write-heavy (~ one transaction per minute taking just a few milliseconds). Also, the app had been running fine before the update for a long time without any reports of this issue. I might be doing something wrong or have changed anything else, but I don’t know what; if you have any ideas, let me know. Any suggestions on what could be the culprit or what else I could try besides downgrading all the way to SQLite 3.21 would be appreciated. Thanks, Daniel Alm P.S.: Our database currently uses the following PRAGMAs: PRAGMA mmap_size = 0; PRAGMA page_size = 4096; PRAGMA cache_size = -10240; PRAGMA foreign_keys = ON; PRAGMA journal_size_limit = 8388608; PRAGMA checkpoint_fullfsync = 1; PRAGMA wal_autocheckpoint = 2048; PRAGMA journal_mode = WAL; Happy to provide any more details as needed. _______________________________________________ sqlite-users mailing list sqlite-users@mailinglists.sqlite.org http://mailinglists.sqlite.org/cgi-bin/mailman/listinfo/sqlite-users
