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Questions tagged [shmmax]

8 questions
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How to set shmall, shmmax, shmmin, etc ... in general and for postgresql

I've used the documentation from PostgreSQL to set it for example this config: >>> cat /proc/meminfo MemTotal: 16345480 kB MemFree: 1770128 kB Buffers: 382184 kB Cached: 10432632 kB SwapCached: 0 kB Active:…
jpic
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2 answers

Postgresql Performance - Adjusting SHMMAX and SHMALL

I've read just about everything there is online about improving postgres performance, but the "right" values for SHMMAX and SHMALL still elude me. The consensus seems to be SHMMAX = total_memory/4 and SHMALL = total_memory/2 are safe starting…
Enrico
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3 answers

how to set the shmmax parameter on mac os x

how should I set the shm* values in Mac Os X 10.5.6 Leopard in a persistent manner?
Alex. S.
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3 answers

What is the default maximum value for /proc/sys/kernel/shmmax

I am having an amiguity as to what the maximum value in shmmax should be set. After having a look at my system's statistics, it shows the following: #cat /proc/sys/kernel/shmmax 18446744073692774399 #ipcs -l ------ Messages Limits -------- max…
Parth Pathak
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2 answers

PostgreSQL server failed to start: request for a shared memory segment exceeded your kernel's SHMMAX parameter

I increased PostgreSQL's shared buffer (among other settings) to 4096M and now PostgreSQL fails to start, giving the error message below. Should I change the kernel's SHMMAX parameter to 4096M? The system has 16GB of RAM. How should this be done?…
Nyxynyx
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High shmmax value in Redhat 6.3

We are using Redhat 6.3 with 30G RAM to host our Postgres server. The (default) shmmax value is 68,719,476,736 In some forums I have read that having an shmmax value larger than the RAM causes extensive paging, but in the Redhat forums it warns…
xpapad
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3 answers

shmmax setting in sysctl.conf not taking effect

We are running RHEL 4 Update 6 and I am going through an Oracle installation. As per the Oracle Installation Guide I am trying to update the shmmax value. As per the guide I have added the following line to /etc/sysctl.conf: kernel.shmmax =…
Patrick
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Is a value of 18446744073692774399 normal for kernel.shmmax?

Context: web server hosted on DigitalOcean with a PostgreSQL database. We were experiencing recurring database crashes for unknown reasons. Eventually I nailed down a faulty query that was overloading the system and am almost sure that's the…
dabadaba
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