Re: [sqlite] Does wal-file support MMAP？

2017-11-19 Thread Simon Slavin
On 19 Nov 2017, at 6:15am, Howard Kapustein wrote: > On 10 Nov 2017, at 8:49am, advancenOO wrote: > >> hAve you optimised your column orders ? > What is optimal? SQLite reads only up to the last column it needs to execute the

Re: [sqlite] Does wal-file support MMAP？

2017-11-18 Thread Howard Kapustein
On 10 Nov 2017, at 8:49am, advancenOO wrote: >hAve you optimised your column orders ? What is optimal? - Howard ___ sqlite-users mailing list sqlite-users@mailinglists.sqlite.org

Re: [sqlite] Does wal-file support MMAP？

2017-11-10 Thread Simon Slavin
On 10 Nov 2017, at 8:49am, advancenOO wrote: > Purely for speed :) > I hope to improve the performance inside sqlite in order to optimize the > performance of the upper applications. As there are so many different scenes > in APPs. hAve you optimised your column

Re: [sqlite] Does wal-file support MMAP？

2017-11-10 Thread advancenOO
Purely for speed :) I hope to improve the performance inside sqlite in order to optimize the performance of the upper applications. As there are so many different scenes in APPs. -- Sent from: http://sqlite.1065341.n5.nabble.com/ ___ sqlite-users

Re: [sqlite] Does wal-file support MMAP？

2017-11-09 Thread Simon Slavin
On 10 Nov 2017, at 5:35am, advancenOO wrote: > In multi-thread scenario, I guess that threads may not use MMAP correctly > after one thread truncates wal-file. And that is the reason MMAP can not be > used together with WAL mode. Are the threads using the same

Re: [sqlite] Does wal-file support MMAP？

2017-11-09 Thread advancenOO
In multi-thread scenario, I guess that threads may not use MMAP correctly after one thread truncates wal-file. And that is the reason MMAP can not be used together with WAL mode. So, I am wondering if I can simply make the size of Wal-file a fixed size to support MMAP for wal-file. -- Sent

Re: [sqlite] Does wal-file support MMAP？

2017-11-08 Thread Dan Kennedy
On 11/09/2017 08:59 AM, advancenOO wrote: I am trying to understand how SQLITE_DEFAULT_MMAP_SIZE works and I think db files can use MMAP by using this compilation option, as Sqlite3PagerGet() mapped to getPageMMap(). And I know "/the current VFS implementations use a mmapped file for the