>Setting the mmap_size will normally help read performance a lot. >However, if you are reading from a ZIPVFS database, the extra layer of >decryption and decompression that sits in between the disk and your >application will render the mmap_size mote - it won't matter.
Thanks very much. What you said is very improtant for me. Because I am reading from a ZIPVFS database. What do you mean of "render the mmap_size mote "? best regards wqg At 2015-12-23 12:05:19, "Richard Hipp" <drh at sqlite.org> wrote: >On 12/22/15, ??? <2004wqg2008 at 163.com> wrote: >>>> >pragma mmap_size= 512000000; >>>> >Pragma page_size = 8192; >>>> >Vacuum; >>>> >Pragma cache_size = N; >> The above code has nothing to do with the speed of retrieving records, >> especially the beginning retrieve records from database. >> Is this the right? >> > >Setting the mmap_size will normally help read performance a lot. >However, if you are reading from a ZIPVFS database, the extra layer of >decryption and decompression that sits in between the disk and your >application will render the mmap_size mote - it won't matter. >-- >D. Richard Hipp >drh at sqlite.org >_______________________________________________ >sqlite-users mailing list >sqlite-users at mailinglists.sqlite.org >http://mailinglists.sqlite.org/cgi-bin/mailman/listinfo/sqlite-users
