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?