Hello, I would like to make writes to my SQLite db faster.
I was thinking about the Async method, but I think I remember reading somewhere that it may cause database corruption. Now I read something on the Mozilla pages, and I don't understand what exactely they are doing. Do they bundle everything in transactions only or do they in fact use the Async method? It is not clear to me by reading through their articles. It would be nice if somebody could clear me up on this issue. Here is the article: Lazy writing Mozilla has relaxed the ACID requirements in order to speed up commits. In particular, we have dropped durability. This means that when a commit returns, you are not guaranteed that the commit has gone through. If the power goes out right away, that commit may (or may not) be lost. However, we still support the other (ACI) requirements. This means that the database will not get corrupted. If the power goes out immediately after a commit, the transaction will be like it was rolled back: the database will still be in a consistent state. Higher commit performance is achieved by writing to the database from a separate thread (see storage/src/mozStorageAsyncIO.cpp<http://mxr.mozilla.org/mozilla-central/source/storage/src/mozStorageAsyncIO.cpp> which is associated with the storage service in storage/src/mozStorageService.cpp<http://mxr.mozilla.org/mozilla-central/source/storage/src/mozStorageService.cpp> ). The main database thread does everything exactly as it did before. However, we have overridden the file operations and everything comes through the AsnycIO module. This file is based on test_async.c<http://www.sqlite.org/cvstrac/rlog?f=sqlite/src/test_async.c>from the sqlite distribution. The AsyncIO module packages writes up in messages and puts them on the write thread's message queue. This write thread waits for messages and processes them as fast as it can. This means that writes, locking, and most importantly, disk syncs, only block the AsyncIO thread. Reads are done synchronously, taking into account unwritten data still in the buffer. _______________________________________________ sqlite-users mailing list sqlite-users@sqlite.org http://sqlite.org:8080/cgi-bin/mailman/listinfo/sqlite-users
