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Re: postgresql is slow with larger table even it is in RAM - Mailing list pgsql-performance

From sathiya psql
Subject Re: postgresql is slow with larger table even it is in RAM
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Msg-id f966c2ee0803250627gdd5f1eai61b0bbb199320fd3@mail.gmail.com
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In response to Re: postgresql is slow with larger table even it is in RAM  (Bill Moran <wmoran@collaborativefusion.com>)
Responses Re: postgresql is slow with larger table even it is in RAM  (Bill Moran <wmoran@collaborativefusion.com>)
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Yes.  It takes your hardware about 3 seconds to read through 700M of ram.

 

Keep in mind that you're not just reading RAM.  You're pushing system
requests through the VFS layer of your operating system, which is treating
the RAM like a disk (with cylinder groups and inodes and blocks, etc) so
you have all that processing overhead as well.  What filesystem did you
format the RAM disk with?
tmpfs

Why are you doing this?  If you have enough RAM to store the table, why
not just allocate it to shared buffers?

just allocating will  make read from hdd to RAM at first time, to eliminate that


are you saying it will take 3 seconds surely if i have 50 lakh record

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