#Sqlite vacuum update#

Very expensive if your database is 100MB+. If you’re too lazy to read all the above, just run this on every database connect: pragma journal_mode = WAL pragma synchronous = normal pragma temp_store = memory pragma mmap_size = 30000000000 More things that must be run manually For writing queries SQLite will always only replace whole pages, so this increases the overhead of write queries. This improved performance and db size a lot for me in one project, but it’s probably only useful if you are storing somewhat large blobs in your database and might not be good for other projects where rows are small. Increase the page size pragma page_size = 32768 Memory mapping can also have implications when there are I/O errors, see the official documentation. If you are on a 32-bit system you can probably only set this to less than 2 3 2 2^ 2 3 2 bytes since the size of the virtual memory space is limited.

If your database is larger than the given mmap_size, the first part of the database will still be memory mapped, the rest will be handled with read() / write() syscalls. Should be much faster, at least on Linux and if you have a fair amount of memory for your SQLite process. The OS will then decide which pages are evicted and which stay in memory based on its usual 'disk caching' logic. Note that it will not use the amount of physical memory, it will just reserve virtual memory. Less syscalls, and pages and caches will be managed by the OS, so the performance of this depends on your operating system. Uses memory mapping instead of read/write calls when the database is < mmap_size in bytes. If your SQLite is creating temporary indices (check with EXPLAIN QUERY PLAN) you should probably create those indexes yourself in any case.Įnable memory mapping pragma mmap_size = 30000000000 sqlite automatically creates temporary indices for some queries. Stores temporary indices / tables in memory. Temporary files location pragma temp_store = memory Off can cause db corruption, though I’ve never had problems. Normal is still completely corruption safe in WAL mode, and means only WAL checkpoints have to wait for FSYNC.

#Sqlite vacuum update#

The default is full, which means every single update has to wait for FSYNC.

Synchronous Commit pragma synchronous = normal This allows multiple concurrent readers even during an open write transaction, and can significantly improve performance. Instead of writing changes directly to the db file, write to a write-ahead-log instead and regularily commit the changes. Some of these are applied permanently, but others are reset on new connection, so it’s recommended to run all of these each time you connect to the database. Run these every time you connect to the DB SQLite is often seen as a toy database only suitable for databases with a few hundred entries and without any performance requirements, but you can scale a SQLite database to multiple GByte in size and many concurrent readers while maintaining high performance by applying the below optimizations. You can still connect to and query the same database concurrently with multiple processes, though only one write operation can happen at the same time. It doesn’t need any server setup or configuration since the SQL logic is run in the host process, and the database consists of only two files you can easily copy or move around. It’s extremely easy to setup, buildable as a single C file with libraries existing for basically all common programming languages. Scaling SQLite databases to many concurrent readers and multiple gigabytes while maintaining 100k SELECTs per second