>All I was able to determine was that setting temp_store = 2 (MEMORY) >did speed up the queries but I've no idea if using that setting is risky >on a lower spec pc.
I "tested" this and setting temp_store to MEMORY is the same as placing the database itself in :memory:. That is, the page_cache and temp_page_cache size (as approriate) has zero effect. That is, the size and memory consumption of both temp objects and objects in the database are limited by the ability of system to allocate virtual storage and once that is used up, an "OutOfMemory" error occurs with whatever consequences may ensure from that thus ensue. If however the database is a file, or the temp_store is a file, then the applicable page cache size specifications provide a best effort limitation (note that it is best effort, not a guarantee) on the amount of memory consumed in the page_cache for each object type (database or temp). So yes, if you run with temp_store = 2 on a computer with 4K of RAM you will have a limitation of being able to use a maximum of 4K of RAM. On the other hand, if you run on a computer that has RAM in excess of the supported process virtual size, then you will keep consuming RAM until the process has allocated all the arena that it is allowed by the OS to allocate before that process gets an out of memory error. Whether or not the "process" memory allocator runs out of allocable arena before the OS runs out of storage is defined by the OS (and the amount of virtual storage actually installed in the computer). So "risky" is a questionable concept. Everything is "risky". I believe what you are trying to express is the probability of an out of memory condition, and that is an entirely different thing. If your application is controlling a life-and-death process then it is quite likely that your CONSEQUENCE of failure is HIGH (immediate death of one of more persons). IF you have the temp_store on disk, then the probability of running out of memory is equal to the probability of running out of disk space, which is a separate question. On the other hand, if you have temp_store in memory and only have 4K of virtual storage, then the probability that you will experience out-of-memory is high. Alternatively, if you are using a computer than has 4 Petabytes of RAM and you have temp_store in memory AND your software is written and running such that it can use all that RAM, then the probability of running out of RAM is remote. Of course, these probabilities do not take into account the probability of "slow lingering death of one or more persons" because, since you cannot afford actual RAM, you instead use spinning-rust backed "Virtual Storage" which introduces "random latency" into your systems. --- 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
