Can you keep your database in-memory and just copy it to your flash periodically? That would give you the most control and minimize the # of writes as much as you want. It's good you recognize that you'll burn your flash out quickly with what you're doing now. There's also the -DSQLITE_TEMP_STORE option which keeps temporary files in-memory. You probably want SQLITE_TEMP_STORE=3 during compilation. ** This function returns true if main-memory should be used instead of ** a temporary file for transient pager files and statement journals. ** The value returned depends on the value of db->temp_store (runtime ** parameter) and the compile time value of SQLITE_TEMP_STORE. The ** following table describes the relationship between these two values ** and this functions return value. ** ** SQLITE_TEMP_STORE db->temp_store Location of temporary database ** ----------------- -------------- ------------------------------ ** 0 any file (return 0) ** 1 1 file (return 0) ** 1 2 memory (return 1) ** 1 0 file (return 0) ** 2 1 file (return 0) ** 2 2 memory (return 1) ** 2 0 memory (return 1) ** 3 any memory (return 1)
Michael D. Black Senior Scientist Advanced Analytics Directorate Northrop Grumman Information Systems ________________________________ From: sqlite-users-boun...@sqlite.org on behalf of Pankaj Chawla Sent: Mon 8/30/2010 5:29 AM To: sqlite-users@sqlite.org Subject: EXTERNAL:[sqlite] Sqlite on NAND flash devices... Hi I have a Sqlite db on an embedded device on which there are inserts happening at a rate of 1 insert every 3 seconds. That being the case if Sqlite does file close/sync every 3 seconds it is going to wear off the NAND in no time. I tried to instead put 2 mins worth of inserts inside a transaction/commit block so that now data only gets committed every 2 mins. What I observe though is that now a journal file gets created during the time transaction/commit block is active and I would assume now all my 3 second updates are going into the journal file. If that is true it means I am still writing to the NAND every 3 seconds through the journal file even though the main DB is only getting synced with the journal every 2 mins. Is this understanding correct? If yes, is there a way to actually reduce the number of writes happening to the NAND flash such that I can save it from quick wear out? If no, how is the writes to the main DB different from the writes to the journal? Thanks Pankaj _______________________________________________ sqlite-users mailing list sqlite-users@sqlite.org http://sqlite.org:8080/cgi-bin/mailman/listinfo/sqlite-users
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