Re: Can't get Dell PE T420 (Perc H710) perform better than a MacMini with PostgreSQL

[Pietro Pugni <pietro.pugni@xxxxxxxxx>]

Hi Josh,

Did you already post the results of:

cat /proc/sys/vm/zone_reclaim_mode

zone_reclaim_mode was set on 0 for all my tests. I’ve also set it to the other values (1, 2, 4) but there was no improvement. Tests results are the following (1 run for each test):

echo 0 > /proc/sys/vm/zone_reclaim_mode

130s

echo 1 > /proc/sys/vm/zone_reclaim_mode

129s

echo 2 > /proc/sys/vm/zone_reclaim_mode

134s

echo 4 > /proc/sys/vm/zone_reclaim_mode

131s

Also, how big did you say your dataset is? Based on the output of free, you're certainly not using all the memory you have.  That could be just because you haven't accessed that much of your dataset, or it could be because zone reclaim is preventing you from using your entire amount of RAM as file system cache.

The table I use for this test is about 20milion row, has less than 10 columns (a small table) and has 4 indexes. Other tables I use are partitioned and consists of a total of 1.6bilion rows, 757 million rows ad so on descending.

Thank you for your help.

Best regards,

 Pietro