On Wed, 8 Feb 2017, Hick Gunter wrote:
Having imlemented a memory-based virtual table complete with indices, full table scan and direct access via rowid (which happens to be the memory address of the row) I can do a batch delete of 100.000 rows (in a table with 1 composite index) in about 2 seconds
The case I am interested is pure read performance of a single column element at a time given properly implemented xBestIndex and xFilter support. Rows are not being added/removed using sqlite.
It is possible that native tables can be faster since the implementation is not limited to the rigid set of callback functions provided for virtual tables to use and of course the amalgamation is optimized by the compiler as one source module.
By tracing the callbacks, we do see that our implementation is not invoking the callbacks more times than necessary (which was not the case before xBestIndex and xFilter support was added). Due to the requirements of the implementation, POSIX reader/writer locks are used so there is some low-contention locking overhead.
Bob -- Bob Friesenhahn bfrie...@simple.dallas.tx.us, http://www.simplesystems.org/users/bfriesen/ GraphicsMagick Maintainer, http://www.GraphicsMagick.org/ _______________________________________________ sqlite-users mailing list sqlite-users@mailinglists.sqlite.org http://mailinglists.sqlite.org/cgi-bin/mailman/listinfo/sqlite-users
