It's here: https://developer.mozilla.org/en/Storage:Performance
On Thu, Dec 31, 2009 at 6:04 PM, Shawn Wilsher <comrade...@gmail.com> wrote: > Where did you see this? It's inaccurate, and if I can, I'll remove it. If > you want to use a proper asynchronous statement execution which wraps your > statement[s] in a transaction, you want to use this: > https://developer.mozilla.org/En/Storage#Asynchronously > > Cheers, > > Shawn Wilsher > Mozilla Developer > > On Thu, Dec 31, 2009 at 8:53 AM, Bert Nelsen <bert.nel...@googlemail.com > >wrote: > > > 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 > > > _______________________________________________ > sqlite-users mailing list > sqlite-users@sqlite.org > http://sqlite.org:8080/cgi-bin/mailman/listinfo/sqlite-users > -- Regards, Bert _______________________________________________ sqlite-users mailing list sqlite-users@sqlite.org http://sqlite.org:8080/cgi-bin/mailman/listinfo/sqlite-users
