RE: pg_dump out of memory for large table with LOB

2018-11-21 Thread Jean-Marc Lessard
Thanks Tom Lane for your answer Same issue for pg_dump and LOB was also reported in https://postgrespro.com/list/thread-id/2211186 Concerning the 25% waste of space we experienced with LOB: We are using LOB because we save jpeg2000 images into the DB. We display them as thumbnails in a 6x10 multi

RE: pg_dump out of memory for large table with LOB

2018-11-21 Thread Jean-Marc Lessard
JMLessard wrote: > What about updates where the bytea do not changed. Does a new copy of the > bytea will be made in the toast table or new row will point to the original > bytea? > > https://www.postgresql.org/docs/current/storage-toast.html says: > > The TOAST management code is triggered only

RE: pg_dump out of memory for large table with LOB

2018-11-15 Thread Jean-Marc Lessard
Thanks to Daniel Verite, nice answer, really helpful :) It summarizes what I have read in the doc and blogs. What about updates where the bytea do not changed. Does a new copy of the bytea will be made in the toast table or new row will point to the original bytea? > https://www.postgresql.org/do

RE: pg_dump out of memory for large table with LOB

2018-11-15 Thread Daniel Verite
Jean-Marc Lessard wrote: > Another area where LOB hurts is the storage. LOB are broken and stored in 2K > pieces. > Due to the block header, only three 2k pieces fit in an 8k block wasting 25% > of space (in fact pgstattuple reports ~ 20%). Yes. bytea stored as TOAST is sliced into pieces

Re: pg_dump out of memory for large table with LOB

2018-11-14 Thread Ron
On 11/14/2018 11:14 AM, Jean-Marc Lessard wrote: Adrien Nayrat wrote: > With 17 million LO, it could eat lot of memory ;) Yes it does. I did several tests and here are my observations. First memory settings are: shared_buffers = 3GB work_mem = 32Mb maintenance_work_mem = 1GB effective_cache_siz

Re: pg_dump out of memory for large table with LOB

2018-11-14 Thread Tom Lane
Jean-Marc Lessard writes: > Would you recommend bytea over LOB considering that the max LOB size is well > bellow 1GB? Yes, probably. The reason that pg_dump has trouble with lots of small BLOBs is the 9.0-era decision to treat BLOBs as independent objects having their own owners, privilege att

RE: pg_dump out of memory for large table with LOB

2018-11-14 Thread Jean-Marc Lessard
Adrien Nayrat wrote: > With 17 million LO, it could eat lot of memory ;) Yes it does. I did several tests and here are my observations. First memory settings are: shared_buffers = 3GB work_mem = 32Mb maintenance_work_mem = 1GB effective_cache_size = 9MB bytea_output = 'escape' The largest LO is

Re: pg_dump out of memory for large table with LOB

2018-11-11 Thread Adrien Nayrat
Hello, On 11/10/18 12:49 AM, Jean-Marc Lessard wrote: > The dumped table is 0.5TB, 17 million rows and LOB uses about 99% of the > space. > If I understand, you have 17 million Large Object? I do not recall exactly and maybe I am wrong. But it seems pg_dump has to allocate memory for each obje

Re: pg_dump out of memory for large table with LOB

2018-11-10 Thread Adrian Klaver
On 11/10/18 2:46 PM, Ron wrote: On 11/09/2018 05:49 PM, Jean-Marc Lessard wrote: I am running PostgreSQL 9.6.5 on x86_64-pc-mingw64, compiled by gcc.exe (Rev5, Built by MSYS2 project) 4.9.2, 64-bit on win2012 with 12Gb RAM The dumped table is 0.5TB, 17 million rows and LOB uses about 99% of

Re: pg_dump out of memory for large table with LOB

2018-11-10 Thread Ron
On 11/09/2018 05:49 PM, Jean-Marc Lessard wrote: I am running PostgreSQL 9.6.5 on x86_64-pc-mingw64, compiled by gcc.exe (Rev5, Built by MSYS2 project) 4.9.2, 64-bit on win2012 with 12Gb RAM The dumped table is 0.5TB, 17 million rows and LOB uses about 99% of the space. The pg_dump consum

pg_dump out of memory for large table with LOB

2018-11-10 Thread Jean-Marc Lessard
I am running PostgreSQL 9.6.5 on x86_64-pc-mingw64, compiled by gcc.exe (Rev5, Built by MSYS2 project) 4.9.2, 64-bit on win2012 with 12Gb RAM The dumped table is 0.5TB, 17 million rows and LOB uses about 99% of the space. The pg_dump consumes the entire system memory and swap, then terminates with

Re: pg_dump out of memory

2018-07-04 Thread Andy Colson
On 07/04/2018 12:31 AM, David Rowley wrote: On 4 July 2018 at 14:43, Andy Colson wrote: I moved a physical box to a VM, and set its memory to 1Gig. Everything runs fine except one backup: /pub/backup# pg_dump -Fc -U postgres -f wildfire.backup wildfirep g_dump: Dumping the contents of table

Re: pg_dump out of memory

2018-07-03 Thread David Rowley
On 4 July 2018 at 14:43, Andy Colson wrote: > I moved a physical box to a VM, and set its memory to 1Gig. Everything > runs fine except one backup: > > > /pub/backup# pg_dump -Fc -U postgres -f wildfire.backup wildfirep > > g_dump: Dumping the contents of table "ofrrds" failed: PQgetResult() fail

Re: pg_dump out of memory

2018-07-03 Thread George Neuner
On Tue, 3 Jul 2018 21:43:38 -0500, Andy Colson wrote: >Hi All, > >I moved a physical box to a VM, and set its memory to 1Gig. Everything >runs fine except one backup: > > >/pub/backup# pg_dump -Fc -U postgres -f wildfire.backup wildfirep > >g_dump: Dumping the contents of table "ofrrds" failed:

Re: pg_dump out of memory

2018-07-03 Thread Adrian Klaver
On 07/03/2018 08:28 PM, Andy Colson wrote: On 07/03/2018 10:21 PM, Adrian Klaver wrote: On 07/03/2018 07:43 PM, Andy Colson wrote: Hi All, I moved a physical box to a VM, and set its memory to 1Gig.  Everything runs fine except one backup: /pub/backup# pg_dump -Fc -U postgres -f wildfire.bac

Re: pg_dump out of memory

2018-07-03 Thread Andy Colson
On 07/03/2018 10:21 PM, Adrian Klaver wrote: On 07/03/2018 07:43 PM, Andy Colson wrote: Hi All, I moved a physical box to a VM, and set its memory to 1Gig.  Everything runs fine except one backup: /pub/backup# pg_dump -Fc -U postgres -f wildfire.backup wildfirep g_dump: Dumping the contents

Re: pg_dump out of memory

2018-07-03 Thread Adrian Klaver
On 07/03/2018 07:43 PM, Andy Colson wrote: Hi All, I moved a physical box to a VM, and set its memory to 1Gig.  Everything runs fine except one backup: /pub/backup# pg_dump -Fc -U postgres -f wildfire.backup wildfirep g_dump: Dumping the contents of table "ofrrds" failed: PQgetResult() faile

pg_dump out of memory

2018-07-03 Thread Andy Colson
Hi All, I moved a physical box to a VM, and set its memory to 1Gig. Everything runs fine except one backup: /pub/backup# pg_dump -Fc -U postgres -f wildfire.backup wildfirep g_dump: Dumping the contents of table "ofrrds" failed: PQgetResult() failed. pg_dump: Error message from server: ERROR: