Performance/Avoid SQLite In Your Next Firefox Feature: Difference between revisions

Performance/Avoid SQLite In Your Next Firefox Feature (view source)

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 * Performance can [http://sqlite.1065341.n5.nabble.com/Coping-with-database-growth-fragmentation-td44781.html#a44782 significantly degenerate over time]; scheduling periodic [https://sqlite.org/lang_vacuum.html rebuilds of the DB] is necessary.
 ** Note that this "vacuuming" only deals with internal fragmentation, not the external [filesystem] fragmentation
-* SQLite uses fsync's to guarantee transaction durability and enable recovery from crashes. fsyncs can be very expensive, and happen relatively frequently in the default rollback-journal mode. This performance/reliability trade-off might not be necessary for simple storage needs.
+** VACUUM empties the free pages space of the database file, that means after a vacuum, until there's new free space, inserts will be a little bit more expensive cause they will have to grow the file
+* SQLite uses fsync's to guarantee transaction durability and enable recovery from crashes. fsyncs can be very expensive, and happen relatively frequently in the default rollback-journal mode. This performance/reliability trade-off might not be necessary for simple storage needs, especially if the important data can be rebuilt at any time.
 * JSON files or log files will show better I/O patterns almost every time, especially if they're compressed and read/written in entirety each time