Re: Hardware upgrade for a high-traffic database - Mailing list pgsql-performance

> -----Original Message-----
> From: Rod Taylor [mailto:pg@rbt.ca]
> Sent: Wednesday, August 11, 2004 5:46 PM
> To: Jason Coene
> Cc: 'Merlin Moncure'; Postgresql Performance
> Subject: Re: [PERFORM] Hardware upgrade for a high-traffic database
>
> > I'm wondering why our PG server is using so little memory...  The system
> has
> > 2GB of memory, though only around 200MB of it are used.  Is there a PG
>
> This is the second time you've said this. Surely you're not implying
> there is 1.8GB Free Memory -- rather than 1.8GB in Buffers or Cache.

Hi Rod,

I was looking at top and vmstat - which always show under 300MB "Active".
We may hit 400MB at peak.  Everything I see (though this isn't my area of
expertise) points to most of the memory simply being unused.  Results below,
am I missing something?

Jason

>
> Send output of the below:
>
> sysctl vm

d01> sysctl vm
vm.vmtotal:
System wide totals computed every five seconds: (values in kilobytes)
===============================================
Processes:              (RUNQ: 1 Disk Wait: 0 Page Wait: 0 Sleep: 149)
Virtual Memory:         (Total: 2101614K, Active 440212K)
Real Memory:            (Total: 2023532K Active 327032K)
Shared Virtual Memory:  (Total: 14356K Active: 3788K)
Shared Real Memory:     (Total: 4236K Active: 2456K)
Free Memory Pages:      88824K

vm.loadavg: { 0.46 0.41 0.42 }
vm.v_free_min: 3312
vm.v_free_target: 13997
vm.v_free_reserved: 749
vm.v_inactive_target: 20995
vm.v_cache_min: 13997
vm.v_cache_max: 27994
vm.v_pageout_free_min: 34
vm.pageout_algorithm: 0
vm.swap_enabled: 1
vm.swap_async_max: 4
vm.dmmax: 32
vm.nswapdev: 1
vm.swap_idle_threshold1: 2
vm.swap_idle_threshold2: 10
vm.v_free_severe: 2030
vm.stats.sys.v_swtch: 627853362
vm.stats.sys.v_trap: 3622664114
vm.stats.sys.v_syscall: 1638589210
vm.stats.sys.v_intr: 3250875036
vm.stats.sys.v_soft: 1930666043
vm.stats.vm.v_vm_faults: 3197534554
vm.stats.vm.v_cow_faults: 2999625102
vm.stats.vm.v_cow_optim: 10093309
vm.stats.vm.v_zfod: 3603956919
vm.stats.vm.v_ozfod: 3104475907
vm.stats.vm.v_swapin: 3353
vm.stats.vm.v_swapout: 3382
vm.stats.vm.v_swappgsin: 3792
vm.stats.vm.v_swappgsout: 7213
vm.stats.vm.v_vnodein: 14675
vm.stats.vm.v_vnodeout: 140671
vm.stats.vm.v_vnodepgsin: 24330
vm.stats.vm.v_vnodepgsout: 245840
vm.stats.vm.v_intrans: 3643
vm.stats.vm.v_reactivated: 35038
vm.stats.vm.v_pdwakeups: 26984
vm.stats.vm.v_pdpages: 335769007
vm.stats.vm.v_dfree: 8
vm.stats.vm.v_pfree: 1507856856
vm.stats.vm.v_tfree: 430723755
vm.stats.vm.v_page_size: 4096
vm.stats.vm.v_page_count: 512831
vm.stats.vm.v_free_reserved: 749
vm.stats.vm.v_free_target: 13997
vm.stats.vm.v_free_min: 3312
vm.stats.vm.v_free_count: 968
vm.stats.vm.v_wire_count: 62039
vm.stats.vm.v_active_count: 44233
vm.stats.vm.v_inactive_target: 20995
vm.stats.vm.v_inactive_count: 343621
vm.stats.vm.v_cache_count: 21237
vm.stats.vm.v_cache_min: 13997
vm.stats.vm.v_cache_max: 27994
vm.stats.vm.v_pageout_free_min: 34
vm.stats.vm.v_interrupt_free_min: 2
vm.stats.vm.v_forks: 45205536
vm.stats.vm.v_vforks: 74315
vm.stats.vm.v_rforks: 0
vm.stats.vm.v_kthreads: 2416
vm.stats.vm.v_forkpages: 1464383994
vm.stats.vm.v_vforkpages: 4259727
vm.stats.vm.v_rforkpages: 0
vm.stats.vm.v_kthreadpages: 0
vm.stats.misc.zero_page_count: 709
vm.stats.misc.cnt_prezero: -972664922
vm.max_proc_mmap: 34952
vm.msync_flush_flags: 3
vm.idlezero_enable: 1
vm.idlezero_maxrun: 16
vm.max_launder: 32
vm.pageout_stats_max: 13997
vm.pageout_full_stats_interval: 20
vm.pageout_stats_interval: 5
vm.pageout_stats_free_max: 5
vm.swap_idle_enabled: 0
vm.defer_swapspace_pageouts: 0
vm.disable_swapspace_pageouts: 0
vm.pageout_lock_miss: 0
vm.zone:
ITEM            SIZE     LIMIT     USED    FREE  REQUESTS

FFS2 dinode:     256,        0,  30156,   4389, 20093512
FFS1 dinode:     128,        0,      0,      0,        0
FFS inode:       140,        0,  30156,   4340, 20093512
SWAPMETA:        276,   121576,     16,    264,    44599
ripcb:           180,    32780,      0,    132,      289
hostcache:        88,    15390,      6,    309,      741
syncache:        104,    15390,      0,    418, 44592418
tcptw:            56,     6603,      3,   1204,   224900
tcpcb:           368,    32769,    136,   4264, 44594153
inpcb:           180,    32780,    139,   4437, 44594153
udpcb:           180,    32780,     10,    144,    85953
unpcb:           140,    32788,      6,    246,   143982
socket:          240,    32768,    152,   4248, 44824378
KNOTE:            64,        0,      0,    434,     7561
PIPE:            172,        0,      8,    222,   352848
NFSNODE:         460,        0,   1596,     92,     2419
NFSMOUNT:        424,        0,      1,     17,        1
DIRHASH:        1024,        0,    238,     86,      287
L VFS Cache:     291,        0,    165,    160,    11956
S VFS Cache:      68,        0,  38283,   3430,  3795133
NAMEI:          1024,        0,      0,    240, 907013101
VNODEPOLL:        60,        0,      1,    131,        2
VNODE:           260,        0,  34104,     36,    34104
g_bio:           136,        0,      0,   5887, 551700514
VMSPACE:         236,        0,    152,    987, 45279840
UPCALL:           44,        0,      0,      0,        0
KSE:              64,        0,   1224,    202,     1224
KSEGRP:          120,        0,   1224,    109,     1224
THREAD:          312,        0,   1224,     84,     1224
PROC:            452,        0,    261,    963, 45282231
Files:            68,        0,    782,   5413, 719968279
4096:           4096,        0,    441,   1935, 90066743
2048:           2048,        0,    237,    423,    25077
1024:           1024,        0,     23,    157,   448114
512:             512,        0,    108,    140,   770519
256:             256,        0,    458,   1102, 70685682
128:             128,        0,   1904,   1041, 186085712
64:               64,        0,   5124,  13042, 1404464781
32:               32,        0,   1281,   1302, 839881182
16:               16,        0,    842,   1548, 1712031683
DP fakepg:        72,        0,      0,      0,        0
PV ENTRY:         28,  2166780, 157829, 769251, 56650653911
MAP ENTRY:        60,        0,   6716,  33280, 2270740046
KMAP ENTRY:       60,    65538,     24,    702,   152938
MAP:             160,        0,      9,     41,        2
VM OBJECT:       132,        0,  21596,  10654, 1136467083
128 Bucket:      524,        0,   3115,      0,        0
64 Bucket:       268,        0,    200,     10,        0
32 Bucket:       140,        0,    191,      5,        0
16 Bucket:        76,        0,     49,      3,        0
UMA Hash:        128,        0,      0,     31,        0
UMA Slabs:        34,        0,   3095,     95,        0
UMA Zones:       432,        0,     52,      2,        0

vm.kvm_size: 1069543424
vm.kvm_free: 364900352

>
> sysctl -a | grep buffers

d01 > sysctl -a | grep buffers
vfs.numdirtybuffers: 52
vfs.lodirtybuffers: 909
vfs.hidirtybuffers: 1819
vfs.numfreebuffers: 7146
vfs.lofreebuffers: 404
vfs.hifreebuffers: 808
>
> top | grep -E "(Mem|Swap):"
>

d01 > top | grep -E "(Mem|Swap):"
Mem: 173M Active, 1346M Inact, 242M Wired, 77M Cache, 112M Buf, 5784K Free
Swap: 4096M Total, 124K Used, 4096M Free