2

Hello,

I've followed the tutorial available here. The installation worked alright, but opening the tile in a browser leads to a 404 error. The only error from the server is "Failed to read cmd on fd 10".

After a long while, the tile is rendered (here, 1600 seconds):

renderd[18586]: DEBUG: DONE TILE default 13 4264-4271 2984-2991 in 1594.968 seconds debug: Creating and writing a metatile to /var/lib/mod_tile/default/13/0/16/11/170/136.meta

How can I solve this problem?

Thank you for your help. Regards, Alex.

asked 17 Jun '14, 16:32

ale42's gravatar image

ale42
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accept rate: 0%

edited 17 Jun '14, 22:51

aseerel4c26's gravatar image

aseerel4c26 ♦
32.2k16239552


2 Answers:
4

You can increase the timeout in your mod_tile configuration, in your case a

ModTileMissingRequestTimeout 1800

would have made the browser wait for up to 1800 seconds instead of returning a 404 after a couple of seconds.

To achieve faster rendering, try one or a combination of the following:

  • have your whole OSM database in RAM or on an SSD disk, or at least on a RAID-10 volume of spinning disks;
  • tune your database (depends on machine, memory, and PostGIS version - often toying with PostGIS memory settings can help);
  • create more indexes (temporarily activate PostGIS logging to find out which queries take most of the time, then create specific index for those);
  • modify your map style to make less expensive queries;
  • pre-render the tiles that you expect are likely to be viewed.
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answered 17 Jun '14, 16:41

Frederik%20Ramm's gravatar image

Frederik Ramm ♦
73.3k866641137
accept rate: 24%

Thanks for your answer Fred.

I will try to put the whole OSM database in RAM.

About the error (Failed to read cmd on fd 10),have you any idea if it can influence the very long time to render tile? How can this be fix?

Tks, Alex.

(19 Jun '14, 12:50) ale42
1

For info I mentioned the "failed to read cmd" issue here:

https://github.com/openstreetmap/mod_tile/issues/77

In my case it didn't have any adverse impact on serving tiles.

(19 Jun '14, 13:21) SomeoneElse ♦

Ok thanks for your answer.

I really don't understand why it's taking this long time to render these tiles.

I try to set up the same configuration on a virtual machine and it takes less than 5 seconds to render one tile. Here, I try this in a OVH server which is more powerfull. I really don't understand.

(19 Jun '14, 13:50) ale42

In that case I would start by comparing things like CPU usage, memory (including swap!) usage and I/O load (via iotop) as well as I/O wait ("wa" in top) between those two systems.

(19 Jun '14, 14:05) scai ♦

My configuration for the server is like this : - RAM : 64 Go DDR ECC 1600 Mhz - CPU : Intel Xeon E5-1620v2 - No SSD - 2 disks x 2 To SATA3HGST Ent. 7K4000

So I don't think my configuration is a problem, isn't it?

I check PostgreSQL queries and these queries don't take more than 1 or 2 ms. So, put the whole database will not be usefull, isn't it?

(20 Jun '14, 09:31) ale42

@ale42 did you resolve this? I have an incredibly slow tile server.

(16 Apr '15, 15:35) haroldship
showing 5 of 6 show 1 more comments
0

Another possibility that could drastically slow down database access would be if for some reason the index creation process failed at import time?

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answered 19 Jun '14, 13:54

SomeoneElse's gravatar image

SomeoneElse ♦
33.0k65343778
accept rate: 16%

2

How can I check that? Or rebuild it?

(19 Jun '14, 13:57) ale42

To answer the first bit, when osm2pgsql completes it'll say something like "Osm2pgsql took 238s overall" (or much longer). It it doesn't say that, it hasn't finished, and indexes probably aren't created.

(28 Aug '16, 01:21) SomeoneElse ♦

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question asked: 17 Jun '14, 16:32

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