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Re: [overpass] Performance question


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  • From: Roland Olbricht <roland.olbricht@gmx.de>
  • To: overpass@listes.openstreetmap.fr
  • Subject: Re: [overpass] Performance question
  • Date: Mon, 21 Nov 2016 06:09:42 +0100

Hi,

Assume a server with many CPU's (6) and many RAM (24 GB). Is there any
thumb rule of how many times faster Overpass queries would be with
Overpass db running totally on a SSD compared with a classic fast hard
disk?

Usually, with a SSD the server gets CPU bound. With a disk, it is usually disk bound.

Does OP profit from more RAM and CPU's?

Please look into your server load. The individual queries are single thread. Hence, it depends on how much queries you would like to run in parallel.

More RAM means more data in the cache. This is highly relevant with a harddisk and probably less relevant with an SSD. I usually had 32 GB machines since the last two or three, and this was enough to let the SSDs stay less than busy, despite 8 CPU cores.

Best regards,

Roland




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