----- Mensagem original ----- | On 10-10-25 03:26 PM, Andrà Volpato wrote: | > | On Mon, Oct 25, 2010 at 2:21 PM, Andrà Volpato | > |<andre.volpato@xxxxxxxxxxxxxxxxxxxxx> wrote: (...) | > |> These times keep repeating after the second run, and I can | > |> ensure AIX isnÂt touching the disks anymore. | > |> IÂve never seen this behaviour before. I heard about Direct I/O | > |> and I was thinking about givng it a shot. | > |> | > |> Any ideas? | > |> | > | | > | I doubt disk/io is the problem. | > | > Me either. | > Like I said, AIX do not touch the storage when runing the query. | > It became CPU-bound after data got into cache. | | Have you confirmed that the hardware is ok on both servers? | The hardware was recently instaled and checked by the vendor team. AIX box is on JS22: PostgreSQL 8.4.4, AIX 5.3-9 64bits, SAN IBM DS3400, 8x450GB SAS 15K Raid-5 8GB RAM (DDR2 667) # lsconf System Model: IBM,7998-61X Processor Type: PowerPC_POWER6 Processor Implementation Mode: POWER 6 Processor Version: PV_6 Number Of Processors: 4 Processor Clock Speed: 4005 MHz CPU Type: 64-bit Kernel Type: 64-bit Memory Size: 7680 MB Debian box is on HS21: PostgreSQL 8.4.4, Debian 4.3.2 64bits, SAN IBM DS3400, 5x300GB SAS 15K Raid-0 7GB RAM (DDR2 667) We are forced to use RedHat on this machine, so we are virtualizing the Debian box. # cpuinfo processor : [0-7] vendor_id : GenuineIntel cpu family : 6 model : 23 model name : Intel(R) Xeon(R) CPU E5420 @ 2.50GHz stepping : 6 cpu MHz : 2500.148 cache size : 6144 KB | Have both OS's been tuned by people that know how to tune the | respective OS's? AIX is very different than Linux, and needs to be tuned | accordingly. WeÂve been tuning AIX for the last 3 weeks, and lots of tuneables got changed. On Debian, we have far more experience, and itÂs been a chalenge to understand how AIX works. Most important tunes: page_steal_method=1 lru_file_repage=0 kernel_heap_psize=64k maxperm%=90 maxclient%=90 minperm%=20 Disk: chdev -l hdisk8 -a queue_depth=24 chdev -l hdisk8 -a reserve_policy=no_reserve chdev -l hdisk8 -a algorithm=round_robin chdev -l hdisk8 -a max_transfer=0x400000 HBA: chdev -l fcs0 -P -a max_xfer_size=0x400000 -a num_cmd_elems=1024 Postgres: shared_buffers = 2304MB effective_io_concurrency = 5 wal_sync_method = fdatasync wal_buffers = 2MB checkpoint_segments = 32 checkpoint_timeout = 10min random_page_cost = 2.5 effective_cache_size = 7144MB Like I said, thereÂs more but this is the most important. | | On AIX can you trace why it is CPU bound? What else is taking the CPU | time, anything?| WeÂre using iostat, svmon and vmstat to trace CPU, swap and IO activity. On 'topas' we saw no disk activity at all, but we get a Wait% about 70%, and about 700 pages/s read in PageIn, no PageOut, no PgspIn and no PgspOut. ItÂs a dedicated server, no process runing besides postgres. | Also, can you provide the output of pg_config from your AIX build? # pg_config BINDIR = /usr/local/pgsql/bin DOCDIR = /usr/local/pgsql/share/doc HTMLDIR = /usr/local/pgsql/share/doc INCLUDEDIR = /usr/local/pgsql/include PKGINCLUDEDIR = /usr/local/pgsql/include INCLUDEDIR-SERVER = /usr/local/pgsql/include/server LIBDIR = /usr/local/pgsql/lib PKGLIBDIR = /usr/local/pgsql/lib LOCALEDIR = /usr/local/pgsql/share/locale MANDIR = /usr/local/pgsql/share/man SHAREDIR = /usr/local/pgsql/share SYSCONFDIR = /usr/local/pgsql/etc PGXS = /usr/local/pgsql/lib/pgxs/src/makefiles/pgxs.mk CONFIGURE = '--enable-integer-datetimes' '--with-readline' '--with-threads' '--with-zlib' '--with-html' 'CC=gcc -maix64' 'LDFLAGS=-Wl,-bbigtoc' CC = gcc -maix64 CPPFLAGS = CFLAGS = -O2 -Wall -Wmissing-prototypes -Wpointer-arith -Wdeclaration-after-statement -Wendif-labels -fno-strict-aliasing -fwrapv CFLAGS_SL = LDFLAGS = -Wl,-bbigtoc -Wl,-blibpath:/usr/local/pgsql/lib:/usr/lib:/lib LDFLAGS_SL = -Wl,-bnoentry -Wl,-H512 -Wl,-bM:SRE LIBS = -lpgport -lz -lreadline -lld -lm VERSION = PostgreSQL 8.4.4 | | -- | Brad Nicholson 416-673-4106 | Database Administrator, Afilias Canada Corp. []Âs, Andre Volpato -- Sent via pgsql-performance mailing list (pgsql-performance@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-performance
