Database Cache Hit Ratio (Warning) - Mailing list pgsql-general

From Rajiv Ranjan
Subject Database Cache Hit Ratio (Warning)
Date
Msg-id CAKeFoKsqxAFnkfD_uYzHP4xjq+QC14yk3wqJmLQaykjZNUzhqw@mail.gmail.com
Whole thread Raw
Responses Re: Database Cache Hit Ratio (Warning)
List pgsql-general
Hi,

Received a Database cache hit ratio warning alert from one of the monitoring tools, the threshold for the “database cache hit ratio %” is 90% for a High and 95% for Critical

Below hardware, CPU, disk and memory utilization of the system. Kindly suggest the parameters for a cache hit ratio or can we simply ignore the warning.  

Hardware:
Architecture:          x86_64
CPU op-mode(s):        32-bit, 64-bit
Byte Order:            Little Endian
CPU(s):                8
On-line CPU(s) list:   0-7
Thread(s) per core:    1
Core(s) per socket:    4
Socket(s):             2
NUMA node(s):          1
Vendor ID:             GenuineIntel
CPU family:            6
Model:                 45
Model name:            Intel(R) Xeon(R) CPU E5-2680 v3 @ 2.50GHz
Stepping:              2
CPU MHz:               2494.224
BogoMIPS:              4988.44
Hypervisor vendor:     VMware
Virtualization type:   full
L1d cache:             32K
L1i cache:             32K
L2 cache:              256K
L3 cache:              30720K
NUMA node0 CPU(s):     0-7


Resource Utilization:

MemTotal:        8008640 kB
MemFree:          145332 kB
MemAvailable:    4710460 kB
Buffers:               0 kB
Cached:          6877160 kB
SwapCached:        19168 kB
Active:          4853536 kB
Inactive:        2575608 kB
Active(anon):    2023944 kB
Inactive(anon):   694232 kB
Active(file):    2829592 kB
Inactive(file):  1881376 kB
Unevictable:           0 kB
Mlocked:               0 kB
SwapTotal:       8388604 kB
SwapFree:        7596796 kB
Dirty:              1660 kB
Writeback:            12 kB
AnonPages:        540584 kB
Mapped:          2189176 kB
Shmem:           2165612 kB
Slab:             212860 kB
SReclaimable:     151188 kB
SUnreclaim:        61672 kB
KernelStack:        4976 kB
PageTables:        90028 kB
NFS_Unstable:          0 kB
Bounce:                0 kB
WritebackTmp:          0 kB
CommitLimit:    12392924 kB
Committed_AS:    4439168 kB
VmallocTotal:   34359738367 kB
VmallocUsed:      169396 kB
VmallocChunk:   34359341052 kB
HardwareCorrupted:     0 kB
AnonHugePages:     77824 kB
CmaTotal:              0 kB
CmaFree:               0 kB
HugePages_Total:       0
HugePages_Free:        0
HugePages_Rsvd:        0
HugePages_Surp:        0
Hugepagesize:       2048 kB
DirectMap4k:      174016 kB
DirectMap2M:     8214528 kB

procs -----------memory---------- ---swap-- -----io---- -system-- ------cpu-----
 r  b   swpd   free   buff  cache   si   so    bi    bo   in   cs us sy id wa st
 3  0 797184 200984      0 7021436    0    0   414   241    0    0  8  1 88  3  0


 PID USER      PR  NI    VIRT    RES    SHR S  %CPU %MEM     TIME+ COMMAND
 3809 postgres  20   0 2439200   2.1g   2.1g S  37.2 27.2 387:11.59 postmaster
 7998 postgres  20   0 2395212 219828 217564 S  11.3  2.7   0:02.53 postmaster
 7999 postgres  20   0 2395208  58384  56200 S  11.3  0.7   0:02.07 postmaster
 8000 postgres  20   0 2395208  59456  57216 S  11.3  0.7   0:02.08 postmaster
 7214 postgres  20   0 2397520   1.9g   1.9g D  11.0 24.4   1:35.25 postmaster
 8003 postgres  20   0 2395208  57848  55656 S  10.3  0.7   0:02.08 postmaster
 8001 postgres  20   0 2399704   1.3g   1.3g D   3.3 17.1   0:15.29 postmaster
21979 postgres  20   0 2412120   2.1g   2.1g S   2.7 27.1 296:22.44 postmaster

Disk Space:
Filesystem                  Size  Used Avail Use% Mounted on
/dev/mapper/localvg-rootlv  242G   68G  175G  28% /
devtmpfs                    3.9G     0  3.9G   0% /dev
tmpfs                       3.9G  4.0K  3.9G   1% /dev/shm
tmpfs                       3.9G  386M  3.5G  10% /run
tmpfs                       3.9G     0  3.9G   0% /sys/fs/cgroup
/dev/sda1                   497M  186M  312M  38% /boot
tmpfs                       783M     0  783M   0% /run/user/1000

--
Thanks,
Rajiv Ranjan 

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