Re: [HACKERS] Implementation of global temporary tables?

On Wed, Jul 15, 2015 at 11:52 AM, Simon Riggs wrote: > On 15 July 2015 at 16:44, Andres Freund wrote: >> On 2015-07-15 16:36:12 +0100, Simon Riggs wrote: >> > On 15 July 2015 at 16:28, Andres Freund wrote: >> > > I think that's generally a fair point. But here we're discussing to >> > > add >> >

Re: [HACKERS] Implementation of global temporary tables?

> > Just to be clear, the idea of a global temp table is that the table def > is available to all users, but the data is private to each session? The table def is visible to all sessions and persistent, but the data is private to each session and temporary. Thanks, Zhaomo

Re: [HACKERS] Implementation of global temporary tables?

2015-07-20 11:07 GMT+02:00 Alvaro Herrera : > Pavel Stehule wrote: > > 2015-07-20 5:33 GMT+02:00 Gavin Flower : > > > > > Would it be difficult to add the ability for one user to share the > > > contents with a list of named other users (roles)? > > > > Probably it is possible, but not for tempora

Re: [HACKERS] Implementation of global temporary tables?

On 2015-07-20 15:33:32 +1200, Gavin Flower wrote: > Would it be difficult to add the ability for one user to share the contents > with a list of named other users (roles)? No need. That feature is called unlogged tables and grants. Doing this for temporary tables would be horrible. They live in p

Re: [HACKERS] Implementation of global temporary tables?

Pavel Stehule wrote: > 2015-07-20 5:33 GMT+02:00 Gavin Flower : > > > Would it be difficult to add the ability for one user to share the > > contents with a list of named other users (roles)? > > Probably it is possible, but not for temporary data - short data are in > process memory, so it are n

Re: [HACKERS] Implementation of global temporary tables?

2015-07-20 5:33 GMT+02:00 Gavin Flower : > On 20/07/15 15:00, Pavel Stehule wrote: > >> >> >> 2015-07-19 21:39 GMT+02:00 Josh Berkus > j...@agliodbs.com>>: >> >> Pavel, All: >> >> Just to be clear, the idea of a global temp table is that the >> table def >> is available to all user

Re: [HACKERS] Implementation of global temporary tables?

On 20/07/15 15:00, Pavel Stehule wrote: 2015-07-19 21:39 GMT+02:00 Josh Berkus >: Pavel, All: Just to be clear, the idea of a global temp table is that the table def is available to all users, but the data is private to each session? yes. Pavel

Re: [HACKERS] Implementation of global temporary tables?

2015-07-19 21:39 GMT+02:00 Josh Berkus : > Pavel, All: > > Just to be clear, the idea of a global temp table is that the table def > is available to all users, but the data is private to each session? > yes. Pavel > > -- > Josh Berkus > PostgreSQL Experts Inc. > http://pgexperts.com >

Re: [HACKERS] Implementation of global temporary tables?

Pavel, All: Just to be clear, the idea of a global temp table is that the table def is available to all users, but the data is private to each session? -- Josh Berkus PostgreSQL Experts Inc. http://pgexperts.com -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make cha

Re: [HACKERS] Implementation of global temporary tables?

On 15 July 2015 at 16:44, Andres Freund wrote: > On 2015-07-15 16:36:12 +0100, Simon Riggs wrote: > > On 15 July 2015 at 16:28, Andres Freund wrote: > > > I think that's generally a fair point. But here we're discussing to add > > > a fair amount of wrinkles with the copy approach. The fact alon

Re: [HACKERS] Implementation of global temporary tables?

On 2015-07-15 16:36:12 +0100, Simon Riggs wrote: > On 15 July 2015 at 16:28, Andres Freund wrote: > > I think that's generally a fair point. But here we're discussing to add > > a fair amount of wrinkles with the copy approach. The fact alone that > > the oid is different will have some ugly conse

Re: [HACKERS] Implementation of global temporary tables?

Simon Riggs writes: > On 15 July 2015 at 16:28, Andres Freund wrote: >> I think that's generally a fair point. But here we're discussing to add >> a fair amount of wrinkles with the copy approach. The fact alone that >> the oid is different will have some ugly consequences. > Why? We are creatin

Re: [HACKERS] Implementation of global temporary tables?

Andres Freund writes: > On 2015-07-15 16:24:52 +0100, Simon Riggs wrote: >> It may be possible to do this, though I'm sure there's a wrinkle somewhere. >> But there doesn't seem to be a need to overload the main feature request >> with additional requirements. Doing that is just scope creep that p

Re: [HACKERS] Implementation of global temporary tables?

On 15 July 2015 at 16:28, Andres Freund wrote: > On 2015-07-15 16:24:52 +0100, Simon Riggs wrote: > > It may be possible to do this, though I'm sure there's a wrinkle > somewhere. > > But there doesn't seem to be a need to overload the main feature request > > with additional requirements. Doing

Re: [HACKERS] Implementation of global temporary tables?

On 2015-07-15 16:24:52 +0100, Simon Riggs wrote: > It may be possible to do this, though I'm sure there's a wrinkle somewhere. > But there doesn't seem to be a need to overload the main feature request > with additional requirements. Doing that is just scope creep that prevents > us getting feature

Re: [HACKERS] Implementation of global temporary tables?

On 15 July 2015 at 15:57, Andres Freund wrote: > On 2015-07-15 16:52:49 +0200, Andres Freund wrote: > > Why do we need to create that copy? We can just use the relfilenode in > > all backends by having the backendid in the filename? Yes, there's a > > some amount of additional code needed, but it

Re: [HACKERS] Implementation of global temporary tables?

> Sounds fine in general. I'm a bit curious to know what are the locking implications of > vivifying the table on access. The locking implications depend on how we interpret the existing commands in the context of global temp tables and I think we should discuss and agree on the behaviors of the c

Re: [HACKERS] Implementation of global temporary tables?

> there is other question - what is effect of ALTER TABLE of global temp table on > instances of this table in active sessions? As I said, we need to first agree on the behaviors of the existing commands. I can think of two options now for ALTER TABLE: 1) only allow ALTER TABLE when there is no

Re: [HACKERS] Implementation of global temporary tables?

On 2015-07-15 16:52:49 +0200, Andres Freund wrote: > Why do we need to create that copy? We can just use the relfilenode in > all backends by having the backendid in the filename? Yes, there's a > some amount of additional code needed, but it's not that much? I > actually think it might end up bei

Re: [HACKERS] Implementation of global temporary tables?

On 2015-07-15 12:58:51 +0100, Simon Riggs wrote: > On 14 July 2015 at 23:20, Jim Nasby wrote: > Pavel's original description of how to do this seem valid, and from the > link Tom agreed in 2009. > > For me the design summary is this > > * CREATE GLOBAL TEMP TABLE creates catalog entries like a n

Re: [HACKERS] Implementation of global temporary tables?

2015-07-15 15:53 GMT+02:00 Zhaomo Yang : > > there is other question - what is effect of ALTER TABLE of global temp > table on > > instances of this table in active sessions? > > As I said, we need to first agree on the behaviors of the existing > commands. I can think of two options now for ALT

Re: [HACKERS] Implementation of global temporary tables?

On 15 July 2015 at 13:26, Andrew Dunstan wrote: > > On 07/15/2015 07:58 AM, Simon Riggs wrote: > > >> For me the design summary is this >> >> * CREATE GLOBAL TEMP TABLE creates catalog entries like a normal table >> but with different relkind >> * When we see a request to INSERT, DEL, UPD, SEL fr

Re: [HACKERS] Implementation of global temporary tables?

2015-07-15 15:21 GMT+02:00 Zhaomo Yang : > > Sounds fine in general. I'm a bit curious to know what are the locking > implications of > vivifying the table on access. > > The locking implications depend on how we interpret the existing commands > in the context of global temp tables and I think we

Re: [HACKERS] Implementation of global temporary tables?

2015-07-15 13:58 GMT+02:00 Simon Riggs : > On 14 July 2015 at 23:20, Jim Nasby wrote: > >> On 7/9/15 12:45 AM, Pavel Stehule wrote: >> >>> >>> 2015-07-09 7:32 GMT+02:00 Zhaomo Yang >> >: >>> >>> > I am not sure, if it is not useless work. >>> >>> I don't unders

Re: [HACKERS] Implementation of global temporary tables?

On 07/15/2015 07:58 AM, Simon Riggs wrote: For me the design summary is this * CREATE GLOBAL TEMP TABLE creates catalog entries like a normal table but with different relkind * When we see a request to INSERT, DEL, UPD, SEL from the temp table, if it does not exist we create it as a TEMP ta

Re: [HACKERS] Implementation of global temporary tables?

On 14 July 2015 at 23:20, Jim Nasby wrote: > On 7/9/15 12:45 AM, Pavel Stehule wrote: > >> >> 2015-07-09 7:32 GMT+02:00 Zhaomo Yang > >: >> >> > I am not sure, if it is not useless work. >> >> I don't understand why an implementation taking approach 2.a would >

Re: [HACKERS] Implementation of global temporary tables?

On 7/9/15 12:45 AM, Pavel Stehule wrote: 2015-07-09 7:32 GMT+02:00 Zhaomo Yang mailto:zhy...@cs.ucsd.edu>>: > I am not sure, if it is not useless work. I don't understand why an implementation taking approach 2.a would be useless. As I said, its performance will be no worse than c

Re: [HACKERS] Implementation of global temporary tables?

> I am not sure, if it is not useless work. I don't understand why an implementation taking approach 2.a would be useless. As I said, its performance will be no worse than current temp tables and it will provide a lot of convenience to users who need to create temp tables in every session. Thank

Re: [HACKERS] Implementation of global temporary tables?

2015-07-09 7:32 GMT+02:00 Zhaomo Yang : > > I am not sure, if it is not useless work. > > I don't understand why an implementation taking approach 2.a would be > useless. As I said, its performance will be no worse than current temp > tables and it will provide a lot of convenience to users who n

Re: [HACKERS] Implementation of global temporary tables?

> more global temp tables are little bit comfortable for developers, I'd like to emphasize this point. This feature does much more than saving a developer from issuing a CREATE TEMP TABLE statement in every session. Here are two common use cases and I'm sure there are more. (1) Imagine in a web a

Re: [HACKERS] Implementation of global temporary tables?

Hi 2015-07-08 9:08 GMT+02:00 Zhaomo Yang : > > more global temp tables are little bit comfortable for developers, > I'd like to emphasize this point. This feature does much more than saving > a developer from issuing a CREATE TEMP TABLE statement in every session. > Here are two common use case

Re: [HACKERS] Implementation of global temporary tables?

On Mon, Feb 2, 2015 at 6:34 PM, Pavel Stehule wrote: > > > 2015-02-02 13:36 GMT+01:00 Atri Sharma : > >> >>> > 1. Main catalogue will be stable. >>> > 2. There is not necessary to implement new storage and it can helps >>> with >>> > transaction support. >>> >>> The amount of complexity that'd be

Re: [HACKERS] Implementation of global temporary tables?

2015-02-02 13:36 GMT+01:00 Atri Sharma : > >> > 1. Main catalogue will be stable. >> > 2. There is not necessary to implement new storage and it can helps with >> > transaction support. >> >> The amount of complexity that'd be involved to store catalog data in a >> separate relation around the cac

Re: [HACKERS] Implementation of global temporary tables?

2015-02-02 13:15 GMT+01:00 Andres Freund : > On 2015-02-02 12:24:44 +0100, Pavel Stehule wrote: > > 2015-02-02 12:04 GMT+01:00 Andres Freund : > > > > 2.b - using unlogged tables for holding statistics, relfilenode, and > all > > > > necessary data > > > > > > I can't follow why that'd achieve any

Re: [HACKERS] Implementation of global temporary tables?

> > > > 1. Main catalogue will be stable. > > 2. There is not necessary to implement new storage and it can helps with > > transaction support. > > The amount of complexity that'd be involved to store catalog data in a > separate relation around the caches and accesses would be significant. I > don

Re: [HACKERS] Implementation of global temporary tables?

On 2015-02-02 12:24:44 +0100, Pavel Stehule wrote: > 2015-02-02 12:04 GMT+01:00 Andres Freund : > > > 2.b - using unlogged tables for holding statistics, relfilenode, and all > > > necessary data > > > > I can't follow why that'd achieve anything? > > > > 1. Main catalogue will be stable. > 2. The

Re: [HACKERS] Implementation of global temporary tables?

2015-02-02 12:04 GMT+01:00 Andres Freund : > Hi, > > On 2015-02-02 11:15:22 +0100, Pavel Stehule wrote: > > Six years ago we did discuss about global temporary tables - persistent > > schema, ephemeral data. > > > > http://postgresql.nabble.com/idea-global-temp-tables-td2007217.html > > > > I am t

Re: [HACKERS] Implementation of global temporary tables?

Hi, On 2015-02-02 11:15:22 +0100, Pavel Stehule wrote: > Six years ago we did discuss about global temporary tables - persistent > schema, ephemeral data. > > http://postgresql.nabble.com/idea-global-temp-tables-td2007217.html > > I am thinking so some reasons why implement this feature are vali

Re: [HACKERS] Implementation of global temporary tables?

2015-02-02 11:51 GMT+01:00 Atri Sharma : > > Some was changed from 2009: >> >> * We have updatable CTE >> >> * We have unlogged tables >> >> Opened questions: >> >> 1. Name and conformance with standard of this feature - because we >> doesn't support modules, a mapping ANSI -> PG should not be tri

Re: [HACKERS] Implementation of global temporary tables?

> Some was changed from 2009: > > * We have updatable CTE > > * We have unlogged tables > > Opened questions: > > 1. Name and conformance with standard of this feature - because we doesn't > support modules, a mapping ANSI -> PG should not be trivial > > 2. Implementation > > I see three possible w

Re: [HACKERS] Implementation of global temporary tables?

2015-02-02 11:15 GMT+01:00 Pavel Stehule : > Hello > > Six years ago we did discuss about global temporary tables - persistent > schema, ephemeral data. > > http://postgresql.nabble.com/idea-global-temp-tables-td2007217.html > > I am thinking so some reasons why implement this feature are valid: >

[HACKERS] Implementation of global temporary tables?

Hello Six years ago we did discuss about global temporary tables - persistent schema, ephemeral data. http://postgresql.nabble.com/idea-global-temp-tables-td2007217.html I am thinking so some reasons why implement this feature are valid: * we can get some performance benefit against current tem