> I've changed the setting a bit:
> (1) Replaced 7.200 disk by a 10.000 one, still sata though.
> (2) Inserting rows only 10x times (instead of 100x times)
> but 80mb each, so having the same amount of 800mb in total.
> (3) Changed the WAL path to the system disk (by the
> great 'junction' trick mentioned in the other posting), so
> actually splitting the write access to the "system" disk and
> the fast "data" disk.
> And here is the frustrating result:
> 1. None of the 4 CPUs was ever more busy than 30% (never
> less idle than 70%),
> 2. while both disks kept being far below the average write
> performance: the "data" disk had 18 peaks of approx. 40 mb
> but in total the average thoughput was 16-18 mb/s.
> * Disabling noatime and similar for ntfs did not change
> things much (thanks though!).
> * A short cross check copying 800mb random data file from
> "system" to "data" disk showed a performance of constantly
> 75 mb/s.
> So, I have no idea what remains as the bottleneck.
Try this :
CREATE TABLE test AS SELECT * FROM yourtable;
This will test write speed, and TOAST compression speed.
Then try this:
CREATE TABLE test (LIKE yourtable);
INSERT INTO test SELECT * FROM yourtable;
This does the same thing but also writes WAL.
I wonder what results you'll get.
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