Re: [HACKERS] REFRESH MATERIALIZED VIEW locklevel

2013-03-08 Thread Nicolas Barbier
2013/3/8 Andres Freund and...@anarazel.de: On 2013-03-07 15:21:35 -0800, Josh Berkus wrote: This limitation is in no way crippling for this feature, or even a major detraction. I still intend to promote the heck out of this feature. Thats scaring me. Because the current state of the

Re: [HACKERS] REFRESH MATERIALIZED VIEW locklevel

2013-03-08 Thread Josh Berkus
Andres, Crossing this over to pgsql-advocacy, because this is really an Advocacy discussion. The point is that a) refreshing is the only way to update materialized views. There's no incremental support. b) refreshing will take a long time (otherwise you wouldn't have create a

Re: [HACKERS] REFRESH MATERIALIZED VIEW locklevel

2013-03-08 Thread Merlin Moncure
On Fri, Mar 8, 2013 at 11:59 AM, Josh Berkus j...@agliodbs.com wrote: Andres, Crossing this over to pgsql-advocacy, because this is really an Advocacy discussion. The point is that a) refreshing is the only way to update materialized views. There's no incremental support. b) refreshing

Re: [HACKERS] REFRESH MATERIALIZED VIEW locklevel

2013-03-08 Thread Joshua D. Drake
On 03/08/2013 10:09 AM, Merlin Moncure wrote: On Fri, Mar 8, 2013 at 11:59 AM, Josh Berkus j...@agliodbs.com wrote: Andres, Further, we get pretty much one and only one chance to promote a new major feature, which is when that feature is first introduced. Improving the feature in the next

[HACKERS] REFRESH MATERIALIZED VIEW locklevel

2013-03-07 Thread Andres Freund
Hi, if I understand things correctly REFRESH MATERIALIZED VIEW locks the materialized view with an AcessExclusiveLock even if the view already contains data. I am pretty sure that will - understandably - confuse users, so I vote for at least including a note about that in the docs. This fact imo

Re: [HACKERS] REFRESH MATERIALIZED VIEW locklevel

2013-03-07 Thread Kevin Grittner
Andres Freund and...@2ndquadrant.com wrote: if I understand things correctly REFRESH MATERIALIZED VIEW locks the materialized view with an AcessExclusiveLock even if the view already contains data. Yeah.  At the time I had to make a decision on that, REINDEX CONCURRENTLY did not seem reliable

Re: [HACKERS] REFRESH MATERIALIZED VIEW locklevel

2013-03-07 Thread Andres Freund
On 2013-03-07 09:55:39 -0800, Kevin Grittner wrote: Andres Freund and...@2ndquadrant.com wrote: if I understand things correctly REFRESH MATERIALIZED VIEW locks the materialized view with an AcessExclusiveLock even if the view already contains data. Yeah.  At the time I had to make a

Re: [HACKERS] REFRESH MATERIALIZED VIEW locklevel

2013-03-07 Thread anara...@anarazel.de
Kevin Grittner kgri...@ymail.com schrieb: Andres Freund and...@2ndquadrant.com wrote: if I understand things correctly REFRESH MATERIALIZED VIEW locks the materialized view with an AcessExclusiveLock even if the view already contains data. Yeah.  At the time I had to make a decision on

Re: [HACKERS] REFRESH MATERIALIZED VIEW locklevel

2013-03-07 Thread Kevin Grittner
anara...@anarazel.de and...@anarazel.de wrote: In the ride home I realized that unless - not that unlikely - you thought about something I didtn't  REFRESH will behave similar to TRUNCATE for repeatable read+ transactions that only access it after REFRESH finished. That is, they will appear

Re: [HACKERS] REFRESH MATERIALIZED VIEW locklevel

2013-03-07 Thread Andres Freund
On 2013-03-07 11:50:11 -0800, Kevin Grittner wrote: anara...@anarazel.de and...@anarazel.de wrote: In the ride home I realized that unless - not that unlikely - you thought about something I didtn't  REFRESH will behave similar to TRUNCATE for repeatable read+ transactions that only

Re: [HACKERS] REFRESH MATERIALIZED VIEW locklevel

2013-03-07 Thread Josh Berkus
Andres, if I understand things correctly REFRESH MATERIALIZED VIEW locks the materialized view with an AcessExclusiveLock even if the view already contains data. I am pretty sure that will - understandably - confuse users, so I vote for at least including a note about that in the docs. +1

Re: [HACKERS] REFRESH MATERIALIZED VIEW locklevel

2013-03-07 Thread Andres Freund
Hi, On 2013-03-07 15:21:35 -0800, Josh Berkus wrote: This fact imo reduces the usability of the matviews features as it stands atm considerably. I think we should be very careful not to advocate its existance much and document very clearly that its work in progress. Working

Re: [HACKERS] REFRESH MATERIALIZED VIEW locklevel

2013-03-07 Thread Josh Berkus
Postgres is currently full of fairly innocent-looking commands which take an unexpected ACCESS EXCLUSIVE lock. For example, DROP CONSTRAINT takes an accessexclusive lock, but it hasn't stopped people from using constraints, and isn't particularly high up on our todo list to fix it. Thats

Re: [HACKERS] REFRESH MATERIALIZED VIEW locklevel

2013-03-07 Thread Andres Freund
On 2013-03-07 15:54:32 -0800, Josh Berkus wrote: Postgres is currently full of fairly innocent-looking commands which take an unexpected ACCESS EXCLUSIVE lock. For example, DROP CONSTRAINT takes an accessexclusive lock, but it hasn't stopped people from using constraints, and isn't