On Feb 11, 2008 1:53 PM, Dennis Cote <[EMAIL PROTECTED]> wrote: > > Stephen Oberholtzer wrote: > > I should note that there's a gross inefficiency when using triggers to > > handle updates or deletes against views; SQLite does the equivalent of > > this: > > > > For UPDATE <view> ... WHERE <condition>, SQLite copies the entire > > source view into the temp table. > > > > SELECT * INTO <temptable> FROM <view> > > > > Then, it iterates over <temptable>, looking for rows that match > > <condition>, and *then* runs the trigger on them. This means that if > > your source view is large, this will run slowly. > > > > I submitted a patch a long while ago to optimize this by turning the > > initial temp-table population into "SELECT * INTO <temptable> FROM > > <view> WHERE <condition>", which worked much faster, but I don't think > > anything came of it. > > > > (my original msg to this list: > > http://readlist.com/lists/sqlite.org/sqlite-users/2/11029.html ) > > > > > > > > Stephen, > > This does seem like a good idea. > > The SQLite mailing list doesn't pass files attached to submissions, so > no one saw your patch. I would suggest creating at ticket at > http://www.sqlite.org/cvstrac/captcha?nxp=/cvstrac/tktnew and posting > your message, or a link to it, along with your patch. > > I suspect the patch itself will probably have to be modified, since > SQLite recently underwent significant changes to its code generation > routines. > > As with all patches, it will be reviewed and accepted much faster if it > passes the test suite. > > > HTH > Dennis Cote
If only you'd been around when I'd posted my message! Nobody said *anything*, so I figured nobody else cared about it. I have reposted my mailing list message, with attachments, here: http://www.sqlite.org/cvstrac/tktview?tn=2938 I have not updated the patch, however. It *should* be pretty straightforward -- looking at it again, it doesn't actually seem to do any VDBE code itself, so who knows? -- -- Stevie-O Real programmers use COPY CON PROGRAM.EXE _______________________________________________ sqlite-users mailing list sqlite-users@sqlite.org http://sqlite.org:8080/cgi-bin/mailman/listinfo/sqlite-users
