Re: Status of the table access method work

2019-06-11 Thread Robert Haas
On Tue, Jun 11, 2019 at 12:32 PM Andres Freund wrote: > Yea, I think there's plenty reasons to want to do something different > than what we're doing. But I'd like to see a concrete proposal before > building API for it... I wasn't intending to propose that you should. We're just in the

Re: Status of the table access method work

2019-06-11 Thread Andres Freund
Hi, On 2019-06-11 11:59:36 -0400, Robert Haas wrote: > On Tue, Jun 11, 2019 at 11:47 AM Alvaro Herrera > wrote: > > On 2019-Apr-10, Alexander Korotkov wrote: > > > Alternative idea is to have MVCC-aware indexes. This approach looks > > > more attractive for me. In this approach you basically

Re: Status of the table access method work

2019-06-11 Thread Peter Geoghegan
On Tue, Jun 11, 2019 at 8:59 AM Robert Haas wrote: > I don't think that including visibility information in indexes is a > bad idea; we've thought about making zheap do this someday. But I > think that we need to use some more sophisticated approach involving, > maybe, undo pointers, or some

Re: Status of the table access method work

2019-06-11 Thread Robert Haas
On Tue, Jun 11, 2019 at 11:47 AM Alvaro Herrera wrote: > On 2019-Apr-10, Alexander Korotkov wrote: > > Alternative idea is to have MVCC-aware indexes. This approach looks > > more attractive for me. In this approach you basically need xmin, > > xmax fields in index tuples. > > "We liked

Re: Status of the table access method work

2019-06-11 Thread Alvaro Herrera
On 2019-Apr-10, Alexander Korotkov wrote: > Alternative idea is to have MVCC-aware indexes. This approach looks > more attractive for me. In this approach you basically need xmin, > xmax fields in index tuples. "We liked freezing xmin so much that we had to introduce freezing for xmax" --

Re: Status of the table access method work

2019-04-18 Thread Simon Riggs
On Wed, 10 Apr 2019 at 18:14, Alexander Korotkov wrote: > Alternative idea is to have MVCC-aware indexes. This approach looks > more attractive for me. In this approach you basically need xmin, > xmax fields in index tuples. On insertion of index tuple you fill > it's xmin. On update,

Re: Status of the table access method work

2019-04-17 Thread Dmitry Dolgov
> On Wed, Apr 17, 2019 at 10:25 PM Andres Freund wrote: > > I assume you're aware, but it's probably not going to be applied for 12... Sure, the patch was mostly to express more clearly what I was thinking about :) > I think most of the read-only stuff just needs to be non-optional, and most >

Re: Status of the table access method work

2019-04-17 Thread Andres Freund
Hi! On 2019-04-17 22:02:24 +0200, Dmitry Dolgov wrote: > > On Fri, Apr 5, 2019 at 10:25 PM Andres Freund wrote: > > > > A second set of limitations is around making more of tableam > > optional. Right now it e.g. is not possible to have an AM that doesn't > > implement insert/update/delete.

Re: Status of the table access method work

2019-04-17 Thread Dmitry Dolgov
> On Fri, Apr 5, 2019 at 10:25 PM Andres Freund wrote: > > A second set of limitations is around making more of tableam > optional. Right now it e.g. is not possible to have an AM that doesn't > implement insert/update/delete. Obviously an AM can just throw an error > in the relevant callbacks,

Re: Status of the table access method work

2019-04-14 Thread Alexander Korotkov
On Wed, Apr 10, 2019 at 8:32 PM Andres Freund wrote: > On 2019-04-10 20:14:17 +0300, Alexander Korotkov wrote: > > Your explanation of existing limitations looks very good and > > convincing. But I think there is one you didn't mention. We require > > new table AMs to basically save old

Re: Status of the table access method work

2019-04-10 Thread Alexander Korotkov
On Wed, Apr 10, 2019 at 8:32 PM Andres Freund wrote: > On 2019-04-10 20:14:17 +0300, Alexander Korotkov wrote: > > Your explanation of existing limitations looks very good and > > convincing. But I think there is one you didn't mention. We require > > new table AMs to basically save old

Re: Status of the table access method work

2019-04-10 Thread Andres Freund
Hi, On 2019-04-10 20:14:17 +0300, Alexander Korotkov wrote: > Your explanation of existing limitations looks very good and > convincing. But I think there is one you didn't mention. We require > new table AMs to basically save old "contract" between heap and > indexes. We have "all or nothing"

Re: Status of the table access method work

2019-04-10 Thread Alexander Korotkov
On Fri, Apr 5, 2019 at 11:25 PM Andres Freund wrote: > I want to thank Haribabu, Alvaro, Alexander, David, Dmitry and all the > others that collaborated on making tableam happen. It was/is a huge > project. Thank you so much for bringing this project to commit! Excellent work! Your explanation

Re: Status of the table access method work

2019-04-09 Thread Andres Freund
Hi, On 2019-04-09 11:17:29 +0200, Dmitry Dolgov wrote: > I'm also curious about that. As far as I can see the main objection against > that was that in this case the recovery process will depend on an extension, > which could violate reliability. I don't think that's a primary concern - although

Re: Status of the table access method work

2019-04-09 Thread Thomas Munro
On Tue, Apr 9, 2019 at 2:12 PM Haribabu Kommi wrote: > I got the same doubt when i looked into some of the UNDO patches > where it tries to modify the core code to add UNDO specific WAL types. > Different AM's may need different set of operations to be WAL logged, > so it may be better for the

Re: Status of the table access method work

2019-04-09 Thread Dmitry Dolgov
> On Tue, Apr 9, 2019 at 4:12 AM Haribabu Kommi > wrote: > > On Sat, Apr 6, 2019 at 7:25 AM Andres Freund wrote: >> >> With regards to storing the rows themselves, the second biggest >> limitation is a limitation that is not actually a part of tableam >> itself: WAL. Many tableam's would want

Re: Status of the table access method work

2019-04-09 Thread Heikki Linnakangas
On 08/04/2019 19:38, Andres Freund wrote: On 2019-04-08 14:53:53 +0300, Heikki Linnakangas wrote: On 05/04/2019 23:25, Andres Freund wrote: - the (optional) bitmap heap scan API - that's fairly intrinsically block based. An AM could just internally subdivide TIDs in a different way,

Re: Status of the table access method work

2019-04-08 Thread Haribabu Kommi
On Sat, Apr 6, 2019 at 7:25 AM Andres Freund wrote: > Hi, > > In this email I want to give a brief status update of the table access > method work - I assume that most of you sensibly haven't followed it > into all nooks and crannies. > > I want to thank Haribabu, Alv

Re: Status of the table access method work

2019-04-08 Thread Andres Freund
Hi On 2019-04-08 14:53:53 +0300, Heikki Linnakangas wrote: > On 05/04/2019 23:25, Andres Freund wrote: > > - the (optional) bitmap heap scan API - that's fairly intrinsically > >block based. An AM could just internally subdivide TIDs in a different > >way, but I don't think a bitmap scan

Re: Status of the table access method work

2019-04-08 Thread Heikki Linnakangas
On 05/04/2019 23:25, Andres Freund wrote: I think what's in v12 - I don't know of any non-cleanup / bugfix work pending for 12 - is a pretty reasonable initial set of features. Hooray! - the (optional) bitmap heap scan API - that's fairly intrinsically block based. An AM could just

Status of the table access method work

2019-04-05 Thread Andres Freund
Hi, In this email I want to give a brief status update of the table access method work - I assume that most of you sensibly haven't followed it into all nooks and crannies. I want to thank Haribabu, Alvaro, Alexander, David, Dmitry and all the others that collaborated on making tableam happen