I have a fairly large DB that I need to only read (not write) as fast as
possible. I open DB with flags
SQLITE_OPEN_READONLY|SQLITE_OPEN_PRIVATECACHE and then run select
queries in 8 threads.
When each thread opens its own connection, DB is read in 8 wallclock
seconds using 23 user seconds.
When DB connection is shared by threads, though, the process reads the
same data in 17 wallclock seconds using 20 user seconds, much slower
overall, killing the parallelism benefit.
Reusing RO connection for some reason makes threads wait for each other
too much. What makes the single connection to slow the process down?
In an attempt to speed it up as much as possible, I was trying to first
copy into :memory: db, so that threads would read only from memory, but
this requires the shared connection and it is slower.
sqlite3-3.12.2
Yuri
_______________________________________________
sqlite-users mailing list
sqlite-users@mailinglists.sqlite.org
http://mailinglists.sqlite.org/cgi-bin/mailman/listinfo/sqlite-users
