On Oct 30, 2015, at 5:56 AM, Richard Hipp <drh at sqlite.org> wrote: >> Will SQLite rewrite the whole row if you just change field2 from one float >> to another? > > Yes. Not just the whole row but the whole page on which that row > resides. And even if SQLite did just try to write the 8 bytes that > changes, your OS and disk controller will both end up writing the > entire sector and/or track, so it amounts to about the same I/O either > way.
I knew it would dirty the whole page. I was thinking about the memory work and ignoring that the disk I/O swamps that. Will it at least avoid dirtying continuation pages if the space before the blob doesn't change? Mark
