I am using pgAdmin for SQL test.
Linux:
EXPLAIN ANALYZE select * from
"Seq Scan on lancamentosteste (cost=0.00..49289.74 rows=1883774 width=92) (actual time=0.016..1194.453 rows=1883699 loops=1)"
"Total runtime: 2139.067 ms"
Windows:
"Seq Scan on lancamentosteste (cost=0.00..49288.67 rows=1883967 width=92) (actual time=0.036..745.409 rows=1883699 loops=1)"
"Total runtime: 797.159 ms"
I did some test reading the disk and monitored with iotop.
#hdparm -t /dev/sdc
/dev/sdc:
Timing buffered disk reads: 730 MB in 3.01 seconds = 242.65 MB/sec
#hdparm -T /dev/sdc
/dev/sdc:
Timing cached reads: 9392 MB in 2.00 seconds = 4706.06 MB/sec
#time sh -c "dd if=/dev/zero of=ddfile bs=8k count=250000 && sync"; rm ddfile
250000+0 registros de entrada
250000+0 registros de saÃda
2048000000 bytes (2,0 GB) copiados, 5,84926 s, 350 MB/s
real 0m9.488s
user 0m0.068s
sys 0m5.488s
In the tests monitoring the disk by iotop, it kept constant the reading between 100MB/s to 350MB/s
By doing the same monitoring on iotop and running SELECT, the disk reading does not exceed 100kb/s, I have the impression that some configuration of LINUX or Postgres is limiting the use of the total capacity of DISCO.
Does anyone know if there is any setting for this?