AFAIK the only way to access single memory database from multiple connections is through shared cache.
2018-05-15 0:27 GMT+02:00, Keith Medcalf <kmedc...@dessus.com>: > >>2018-05-13 12:50 GMT+02:00, Techno Magos : > >>> Hello > >>> I do not have clear examples to post on this but would like to >>> report findings around multi threaded read access (single process) in a >>> large system that uses sqlite. > >>> This may be a known issue/restriction of memory sqlite behaviour, >>> but wanted to check with the list first: > >>> 1. Running 2, 3, ... 6 multi threaded readers of a single *memory >>> *sqlite database (via shared cache mode) on an 8 core cpu shows no >>> throughput gain at all compared to single threaded throughput. >>> In fact, it shows a throughput drop: i.e. if a single thread can >>> do N simple queries/sec, 2 threads .. up to 6 threads do a little >>> less (10% drop) in total. This suggests that access to memory >>> sqlite can only be serialized? > > No one has asked the $10 million dollar question yet ... why are you doing > this? It certainly does not sound like you have a highly constrained > itty-bitty wee boxen for which the "shared cache" was designed (ie, you seem > to have more that 4 cycles per second of CPU and 10 bytes of memory). > > So what was the configuration which you WERE PREVIOUSLY USING which was > deficient and for which you are trying this optimization? > > Everyone knows that when you use "shared cache mode" you are trading off > memory and CPU cycles against performance. Shared Cache Mode is designed so > that if you are *really* so inclined you can run SQLite on your Tandy Pocket > Computer too (https://en.wikipedia.org/wiki/Tandy_Pocket_Computer) > > --- > The fact that there's a Highway to Hell but only a Stairway to Heaven says a > lot about anticipated traffic volume. > > > > > _______________________________________________ > sqlite-users mailing list > sqlite-users@mailinglists.sqlite.org > http://mailinglists.sqlite.org/cgi-bin/mailman/listinfo/sqlite-users > _______________________________________________ sqlite-users mailing list sqlite-users@mailinglists.sqlite.org http://mailinglists.sqlite.org/cgi-bin/mailman/listinfo/sqlite-users
