I’m using this configuration
<cache name="cache_sqlite" type="sqlite3">
<dbfile>/var/www/vhosts/buchananmapping.co.uk/httpdocs/maps/cache/{tileset}/{grid}/{z}/{x}-{y}.sqlite3</dbfile>
<xcount>10000</xcount>
<ycount>10000</ycount>
<pragma name="max_page_count">1573741823</pragma>
</cache>
<source name="bcmaps" type="wms">
<getmap>
<params>
<FORMAT>image/png</FORMAT>
<LAYERS>miniscale</LAYERS>
<MAP>…/maps/bcmaps.map</MAP>
</params>
</getmap>
<http>
<url>https://.../cgi-bin/mapserv?</url>
</http>
</source>
<tileset name="bccache">
<source>bcmaps</source>
<cache>cache_sqlite</cache>
<grid>bcgrid</grid>
<format>PNG</format>
<metatile>4 4</metatile>
<metabuffer>0</metabuffer>
<expires>2628000</expires>
</tileset>
<grid name="bcgrid">
<metadata>
<title>BC custom grid</title>
</metadata>
<srs>EPSG:27700</srs>
<size>128 128</size>
<extent>0 0 700000 1250000</extent>
<resolutions>280 140 70 28 14 7 6.16 2.8 1.4 0.7</resolutions>
</grid>
<format name="mypng" type="PNG">
<compression>best</compression>
</format>
It supposed to have a limit that it’s the full EPSG extent
Sebastiano Laini
Web Developer
From: Travis Kirstine [mailto:traviskirst...@gmail.com]
Sent: 22 February 2019 13:57
To: Sebastiano Laini <sebastiano.la...@buchanancomputing.co.uk>
Cc: mapserver-users@lists.osgeo.org
Subject: Re: [mapserver-users] mapcache seed slow
The time you have indicated seems excessive to seed the UK. My guess is that
the current process it seeding the extents of your grid (world?) but default.
I've seeded the province of ontario 1 million km2 z0-17 in about 2 weeks using
a sqlite cache
Ramping up the -n will only bottle neck the process more (same with the -p
flag) the limiting factor is SQLite and it limitation on concurrent writes (I
use -n 4). I've noticed that if you try to use other sqlite3 journal modes you
can degrade performance
(http://osgeo-org.1560.x6.nabble.com/mapcache-sqlite-cache-large-wal-files-and-blocked-checkpoints-when-seeding-td5377571.html).
I would just use most basic cache config as a starting point. BTW using SSD
should increase the SQLite writes as well (if you are lucky enough to have them)
<cache name="sqlite" type="sqlite3">
<dbfile>./{tileset}.sqlite3</dbfile>
</cache>
There are a few things that you could do when seeding to speed up the process:
Use the "restricted_extent" parameter in the tileset grid to limit the number
of tiles
Example
<tileset name="ontario_2018">
<source>ontario_2018_wms</source>
<cache>sqlite</cache>
<grid out-of-zoom-strategy="reassemble" max-cached-zoom="19"
restricted_extent="-12829476.786723 7281268.350007 -12618425.953856
7521514.261991">gmaps</grid>
<format>mixed</format>
<metatile>5 5</metatile>
</tileset>
Use a polygon shapefile (or other ogr datasource) to limit the seeding using
the -d flag in mapcache_seed command (note the projection of the datasource
should be the same as the grid)
Use a larger metatile when seeding (-M flag override in command line).
Mapcache will "bulk" insert the resultant tiles based on the metatile - if
<metatile>5 5</metatile> mapcache will insert 25 tiles at a time if <metatile>8
8</metatile> it will do 64 (I think this is the way it works). The limiting
factor here is trying to balance this with your source WMS performance. I use
8,8 when seeding
Regards
On Fri, 22 Feb 2019 at 06:35, Sebastiano Laini
<sebastiano.la...@buchanancomputing.co.uk<mailto:sebastiano.la...@buchanancomputing.co.uk>>
wrote:
Hi all,
I’m trying to seed the whole UK at all zoom lv with these resolutions
<resolutions>280 140 70 28 14 7 6.16 2.8 1.4 0.7</resolutions>
But after 13 days it arrives at the 5th level where before I kill the process
it seed just 900MB on that level.
This is my script
su -s /bin/sh apache -c "/usr/local/bin/mapcache_seed -c
/usr/local/src/mapcache-1.6.1/build/mapcache.xml -t bccache -g bcgrid -z 5,6 –n
400" 2>&1> /var/www/vhosts/$SITE/scripts/cache_log.txt
I know that in the documentation say that –n should be less or max the number
of cpu in the server but is really slow if I put 2, so I tried with 100 and
after 13 days that was the result so now I’m trying 400
Is there something else I can use to speed up the seed? I’m using the SQlite
cache method
Should I use the -p (| –nprocesses: number of parallel processes that should be
used to request tiles from the WMS source) Instead of the –n parameter?
Sebastiano Laini
Web Developer
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