All,

I'm trying to estimate the size of my hot data set, and wanted to get some
validation that I'm doing this correctly.

Basically, I'm using the sum(heap_blks_read + idx_blks_read) from
pg_statio_all_tables, and diffing the numbers over a period of time (1 hour
at least).  Is this a fair estimate?  The reason for doing this is we are
looking at new server hardware, and I want to try and get enough ram on the
machine to keep the hot data in memory plus provide room for growth.

Thanks,

Chris

Example:



  *Time*

*Total Blocks*

2011-02-16 11:25:34.621874-05

123,260,464,427.00

2011-02-16 12:25:46.486719-05

123,325,880,943.00



To get the hot data for this hour (in KB), I'm taking:


 (123,325,880,943.00 - 123,260,464,427.00)* 8 = 523,332,128KB


Correct?

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