Re: [HACKERS] WAL CPU overhead/optimization (was Master-slave visibility order)

2013-09-03 Thread Robert Haas
On Thu, Aug 29, 2013 at 8:22 PM, Ants Aasma a...@cybertec.at wrote: I might give it a shot later this cycle as I have familiarized my self with the problem domain anyway. I understand the appeal of staying with what we have, but this would cap the speedup at 4x and has large caveats with the

Re: [HACKERS] WAL CPU overhead/optimization (was Master-slave visibility order)

2013-09-03 Thread Hannu Krosing
On 09/03/2013 05:27 PM, Robert Haas wrote: On Thu, Aug 29, 2013 at 8:22 PM, Ants Aasma a...@cybertec.at wrote: I might give it a shot later this cycle as I have familiarized my self with the problem domain anyway. I understand the appeal of staying with what we have, but this would cap the

Re: [HACKERS] WAL CPU overhead/optimization (was Master-slave visibility order)

2013-09-03 Thread Andres Freund
On 2013-09-03 23:25:01 +0200, Hannu Krosing wrote: On 09/03/2013 05:27 PM, Robert Haas wrote: On Thu, Aug 29, 2013 at 8:22 PM, Ants Aasma a...@cybertec.at wrote: I might give it a shot later this cycle as I have familiarized my self with the problem domain anyway. I understand the appeal of

Re: [HACKERS] WAL CPU overhead/optimization (was Master-slave visibility order)

2013-08-30 Thread k...@rice.edu
On Fri, Aug 30, 2013 at 03:22:37AM +0300, Ants Aasma wrote: On Fri, Aug 30, 2013 at 3:02 AM, Andres Freund and...@2ndquadrant.com wrote: I am not sure hot cache large buffer performance is really the interesting case. Most of the XLogInsert()s are pretty small in the common workloads. I

[HACKERS] WAL CPU overhead/optimization (was Master-slave visibility order)

2013-08-29 Thread Andres Freund
On 2013-08-30 01:10:40 +0300, Ants Aasma wrote: On Fri, Aug 30, 2013 at 12:33 AM, Andres Freund and...@2ndquadrant.com wrote: FWIW, WAL is still the major bottleneck for INSERT heavy workloads. The per CPU overhead actually minimally increased (at least in my tests), it just scales

Re: [HACKERS] WAL CPU overhead/optimization (was Master-slave visibility order)

2013-08-29 Thread Ants Aasma
On Fri, Aug 30, 2013 at 1:30 AM, Andres Freund and...@2ndquadrant.com wrote: On 2013-08-30 01:10:40 +0300, Ants Aasma wrote: On Fri, Aug 30, 2013 at 12:33 AM, Andres Freund and...@2ndquadrant.com wrote: FWIW, WAL is still the major bottleneck for INSERT heavy workloads. The per CPU

Re: [HACKERS] WAL CPU overhead/optimization (was Master-slave visibility order)

2013-08-29 Thread Andres Freund
On 2013-08-30 02:53:54 +0300, Ants Aasma wrote: On Fri, Aug 30, 2013 at 1:30 AM, Andres Freund and...@2ndquadrant.com wrote: On 2013-08-30 01:10:40 +0300, Ants Aasma wrote: On Fri, Aug 30, 2013 at 12:33 AM, Andres Freund and...@2ndquadrant.com wrote: FWIW, WAL is still the major

Re: [HACKERS] WAL CPU overhead/optimization (was Master-slave visibility order)

2013-08-29 Thread Ants Aasma
On Fri, Aug 30, 2013 at 3:02 AM, Andres Freund and...@2ndquadrant.com wrote: I am not sure hot cache large buffer performance is really the interesting case. Most of the XLogInsert()s are pretty small in the common workloads. I vaguely recall trying 8 and getting worse performance on many