Re: [HACKERS] Sync Rep at Oct 5

2010-10-07 Thread Fujii Masao
On Wed, Oct 6, 2010 at 4:06 PM, Simon Riggs si...@2ndquadrant.com wrote: The problem is how much WAL is stored on (any) node. Currently that is wal_keep_segments, which doesn't work very well, but I've seen no better ideas that cover all important cases. What about allowing the master to read

Re: [HACKERS] Sync Rep at Oct 5

2010-10-07 Thread Steve Singer
On 10-10-07 05:52 AM, Fujii Masao wrote: On Wed, Oct 6, 2010 at 4:06 PM, Simon Riggssi...@2ndquadrant.com wrote: The problem is how much WAL is stored on (any) node. Currently that is wal_keep_segments, which doesn't work very well, but I've seen no better ideas that cover all important cases.

Re: [HACKERS] Sync Rep at Oct 5

2010-10-07 Thread Fujii Masao
On Thu, Oct 7, 2010 at 8:46 PM, Steve Singer ssin...@ca.afilias.info wrote: Then you have to deal with telling the archive how long it needs to keep WAL segments because the master might ask for them back. Yeah, it's not easy to determine how long we should keep the archived WAL files. We need

Re: [HACKERS] Sync Rep at Oct 5

2010-10-07 Thread Robert Haas
On Thu, Oct 7, 2010 at 9:08 AM, Fujii Masao masao.fu...@gmail.com wrote: On Thu, Oct 7, 2010 at 8:46 PM, Steve Singer ssin...@ca.afilias.info wrote: Then you have to deal with telling the archive how long it needs to keep WAL segments because the master might ask for them back. Yeah, it's not

Re: [HACKERS] Sync Rep at Oct 5

2010-10-06 Thread Simon Riggs
On Tue, 2010-10-05 at 11:30 -0400, Steve Singer wrote: Also on the topic of failover how do we want to deal with the master failing over. Say M-{S1,S2} and M fails and we promote S1 to M1. Can M1-S2? What if S2 was further along in processing than S1 when M failed? I don't think we

[HACKERS] Sync Rep at Oct 5

2010-10-05 Thread Simon Riggs
This is an attempt to compile everybody's stated viewpoints and come to an understanding about where we are and where we want to go. The idea from here is that we discuss what we are trying to achieve (requirements) and then later come back to how (design). To explain replication I use a

Re: [HACKERS] Sync Rep at Oct 5

2010-10-05 Thread Steve Singer
On 10-10-05 04:32 AM, Simon Riggs wrote: This is an attempt to compile everybody's stated viewpoints and come to an understanding about where we are and where we want to go. The idea from here is that we discuss what we are trying to achieve (requirements) and then later come back to how

Re: [HACKERS] Sync Rep at Oct 5

2010-10-05 Thread Simon Riggs
On Tue, 2010-10-05 at 11:30 -0400, Steve Singer wrote: Will read-only queries running on a slave hold up transactions from being applied on that slave? I suspect that for most people running with 'apply' they would want the answer to be 'no'. Are we going to revisit the standby query