Re: [HACKERS] Index-only scans and non-MVCC snapshots

2014-06-27 Thread Ryan Johnson
On 27/06/2014 8:20 AM, Alvaro Herrera wrote: Ryan Johnson wrote: On 26/06/2014 11:04 PM, Alvaro Herrera wrote: Ryan Johnson wrote: As part of a research project, I'm trying to change Read Committed isolation to use HeapTupleSatisfiesNow rather than acquiring a new snapshot at every command [1]

Re: [HACKERS] Index-only scans and non-MVCC snapshots

2014-06-27 Thread Andres Freund
On 2014-06-27 08:39:13 -0600, Ryan Johnson wrote: > On 27/06/2014 3:14 AM, Andres Freund wrote: > >On 2014-06-26 22:47:47 -0600, Ryan Johnson wrote: > >>Hi, > >> > >>As part of a research project, I'm trying to change Read Committed isolation > >>to use HeapTupleSatisfiesNow rather than acquiring a

Re: [HACKERS] Index-only scans and non-MVCC snapshots

2014-06-27 Thread Ryan Johnson
On 27/06/2014 3:14 AM, Andres Freund wrote: On 2014-06-26 22:47:47 -0600, Ryan Johnson wrote: Hi, As part of a research project, I'm trying to change Read Committed isolation to use HeapTupleSatisfiesNow rather than acquiring a new snapshot at every command [1]. Things appear to have gone reaso

Re: [HACKERS] Index-only scans and non-MVCC snapshots

2014-06-27 Thread Alvaro Herrera
Ryan Johnson wrote: > On 26/06/2014 11:04 PM, Alvaro Herrera wrote: > >Ryan Johnson wrote: > >>As part of a research project, I'm trying to change Read Committed > >>isolation to use HeapTupleSatisfiesNow rather than acquiring a new > >>snapshot at every command [1]. > >Are you aware of this? > > >

Re: [HACKERS] Index-only scans and non-MVCC snapshots

2014-06-27 Thread Andres Freund
On 2014-06-26 22:47:47 -0600, Ryan Johnson wrote: > Hi, > > As part of a research project, I'm trying to change Read Committed isolation > to use HeapTupleSatisfiesNow rather than acquiring a new snapshot at every > command [1]. Things appear to have gone reasonably well so far, except > certain q

Re: [HACKERS] Index-only scans and non-MVCC snapshots

2014-06-26 Thread Ryan Johnson
On 26/06/2014 11:04 PM, Alvaro Herrera wrote: Ryan Johnson wrote: As part of a research project, I'm trying to change Read Committed isolation to use HeapTupleSatisfiesNow rather than acquiring a new snapshot at every command [1]. Are you aware of this? commit 813fb0315587d32e3b77af1051a0ef517

Re: [HACKERS] Index-only scans and non-MVCC snapshots

2014-06-26 Thread Alvaro Herrera
Ryan Johnson wrote: > As part of a research project, I'm trying to change Read Committed > isolation to use HeapTupleSatisfiesNow rather than acquiring a new > snapshot at every command [1]. Are you aware of this? commit 813fb0315587d32e3b77af1051a0ef517d187763 Author: Robert Haas Date: Thu A

[HACKERS] Index-only scans and non-MVCC snapshots

2014-06-26 Thread Ryan Johnson
Hi, As part of a research project, I'm trying to change Read Committed isolation to use HeapTupleSatisfiesNow rather than acquiring a new snapshot at every command [1]. Things appear to have gone reasonably well so far, except certain queries fail with "ERROR: non-MVCC snapshots are not supp