Обсуждение: Presentation
The boss cleared my de-company info-ified pg presentation. It deals with PG features, crude comparison to other dbs, install, admin, and most importantly - optimization & quirks. Its avail in powerpoint and (ugg) powerpoint exported html. Let me know if there are blatant errors, etc in there. Maybe even slightly more subtle blatant errors :) The people here thought it was good. http://postgres.jefftrout.com/ -- Jeff Trout <jeff@jefftrout.com> http://www.jefftrout.com/ http://www.stuarthamm.net/
Jeff wrote: > Let me know if there are blatant errors, etc in there. > Maybe even slightly more subtle blatant errors :) Some minor nitpicks, * Slide 5, postgresql already features 64 bit port. The sentence is slightly confusing * Same slide. IIRC postgresql always compresses bytea/varchar. Not too much sure about which but there is something that is compressed by default..:-) * Tablespaces has a patch floating somewhere. IIRC Gavin Sherry is the one who is most ahead of it. For all goodness, they will feature in 7.5 and design is done. There aren't much issues there. * Mysql transaction breaks down if tables from different table types are involved. * Mysql transactions do not feature constant time commit/rollback like postgresql. The time to rollback depends upon size of transaction * Mysql does not split large files in segments the way postgresql do. Try storing 60GB of data in single mysql table. * Slide on informix. It would be better if you mention what database you were using on your pentium. Assuming postgresql is fine, but being specific helps. * Slide on caching. Postgresql can use 7000MB of caching. Important part is it does not lock that memory in it's own process space. OS can move around buffer cache but not memory space of an application. * Installation slide. We can do without 'yada' for being formal, right..:-) (Sorry if thats too nitpicky but couldn't help it..:-)) * initdb could be coupled with configure/make install but again, it's a matter of choice. * Slide on configuration. 'Reliable DB corruption' is a confusing term. 'DB corruption for sure' or something on that line would be more appropriate especially if presentation is read in documentation form and not explained in a live session. but you decide. * I doubt pg_autovacuum will be in core source but predicting that long is always risky..:-) * Using trigger for maintening a row count would generate as much dead rows as you wanted to avoid in first place..:-) All of them are really minor. It's a very well done presentation but 45 slides could be bit too much at a time. I suggest splitting the presentation in 3. Intro and comparison, features, administration, programming and tuning. Wow.. they are 5..:-) Can you rip out informix migration? It could be a good guide by itself. Thanks again for documentation. After you decide what license you want to release it under, the team can put it on techdocs.postgresql.org.. Again, thanks for a good presentation.. Shridhar
> * Same slide. IIRC postgresql always compresses bytea/varchar. Not too much sure > about which but there is something that is compressed by default..:-) I'm not sure about that. Even toasted values are not always compressed, though they certainly can be and usually are.
Вложения
Jeff, > Its avail in powerpoint and (ugg) powerpoint exported html. I can probably convert it to OpenOffice.org and Flash. OK? -- Josh Berkus Aglio Database Solutions San Francisco
On Wed, 8 Oct 2003, Shridhar Daithankar wrote: Thanks for the nitpicks :) I've taken some into consideration. I also signed onto the advocacy list so I can be in on discussions there. Feel free to convert to whatever format you'd like. I originally started working on it in OpenOffice, but I got mad at it. So I switched to powerpoint and got mad at that too :) -- Jeff Trout <jeff@jefftrout.com> http://www.jefftrout.com/ http://www.stuarthamm.net/
On Wed, 8 Oct 2003, Shridhar Daithankar wrote: > * Same slide. IIRC postgresql always compresses bytea/varchar. Not too much sure > about which but there is something that is compressed by default..:-) > * Tablespaces has a patch floating somewhere. IIRC Gavin Sherry is the one who > is most ahead of it. For all goodness, they will feature in 7.5 and design is For the sake of things, I didn't include any features a patch provides. I did include things that may appear in contrib/. > * Mysql transaction breaks down if tables from different table types are involved. > * Mysql transactions do not feature constant time commit/rollback like > postgresql. The time to rollback depends upon size of transaction > * Mysql does not split large files in segments the way postgresql do. Try > storing 60GB of data in single mysql table. I didn't add these ones. The user can figure this one out. Perhaps when we/me expands this into multiple documents we can expand on this. > * Slide on caching. Postgresql can use 7000MB of caching. Important part is it > does not lock that memory in it's own process space. OS can move around buffer > cache but not memory space of an application. I'm guilty of this myself - when I first started pg I was looking for a way to make it use a zillion megs of memory like we have informix do - Perhaps I'll reword that segment.. the point was to show PG relies on the OS to do a lot of caching and that it doesn't do it itself. > * Using trigger for maintening a row count would generate as much dead rows as > you wanted to avoid in first place..:-) We all know this.. but it is a way to get a fast select count(*) from table > All of them are really minor. It's a very well done presentation but 45 slides > could be bit too much at a time. I suggest splitting the presentation in 3. > Intro and comparison, features, administration, programming and tuning. Wow.. > they are 5..:-) > Yeah. What I'd really love to do is de-powerpointify it and make it a nice set of "real" web pages. > Can you rip out informix migration? It could be a good guide by itself. > I agree. It would be good to rip out. I think we have the oracle guide somewhere.. I've put this updated on up on hte postgres.jefftrout.com site along with openoffice version. -- Jeff Trout <jeff@jefftrout.com> http://www.jefftrout.com/ http://www.stuarthamm.net/
On Wed, 2003-10-08 at 11:02, Jeff wrote: > The boss cleared my de-company info-ified pg presentation. Slide 37: as far as I know, reordering of outer joins is not implemented in 7.4 -Neil
On Wed, 8 Oct 2003, Neil Conway wrote: > On Wed, 2003-10-08 at 11:02, Jeff wrote: > > The boss cleared my de-company info-ified pg presentation. > > Slide 37: as far as I know, reordering of outer joins is not implemented > in 7.4 > Huh. I could have sworn Tom did something like that. Perhaps I am thinking of something else. You had to enable some magic GUC. Maybe he did a test and it never made it in. -- Jeff Trout <jeff@jefftrout.com> http://www.jefftrout.com/ http://www.stuarthamm.net/
On Wed, 2003-10-08 at 15:38, Jeff wrote: > Huh. I could have sworn Tom did something like that. > Perhaps I am thinking of something else. > You had to enable some magic GUC. Perhaps you're thinking of the new GUC var join_collapse_limit, which is related, but doesn't effect the reordering of outer joins. -Neil
Jeff <threshar@torgo.978.org> writes:
> On Wed, 8 Oct 2003, Neil Conway wrote:
>> Slide 37: as far as I know, reordering of outer joins is not implemented
>> in 7.4
> Huh. I could have sworn Tom did something like that.
Not yet. 7.4 can reorder *inner* joins that happen to be written
with JOIN syntax.
regards, tom lane