On 11/14/18, Aubrey Barnard <barn...@cs.wisc.edu> wrote: > > $ ~/opt/bin/sqlite3 -pagecache 4096 1234 :memory: "pragma cache_size" > "pragma cache_size = -1000" "pragma cache_size" > Expected output: > -4936 > -1000 > Actual output: > -2000 > -1000
The PRAGMA cache_size=N sets a soft upper bound on the number of cache buffers that will be used. The -pagecache option uses sqlite3_config(SQLITE_CONFIG_PAGECACHE) to use a separate memory allocation as the initial memory pull from which to draw cache buffers. These are different things, and so one does not necessarily change the other. The PRAGMA cache_size=N is used to limit memory usage. The SQLITE_CONFIG_PAGECACHE option is designed to reduce memory fragmentation. See https://www.sqlite.org/malloc.html#_page_cache_memory for further information on what that means and why it is important for some systems. (Hint: Unless you are working on a safety-critical embedded system, this probably is not important to you.) -- D. Richard Hipp d...@sqlite.org _______________________________________________ sqlite-users mailing list sqlite-users@mailinglists.sqlite.org http://mailinglists.sqlite.org/cgi-bin/mailman/listinfo/sqlite-users
