Paul,
This sounds like you have error in your mapfile. you might try posting
it to the list if you can't figure it out yourself.
There also might be some mapfile tools or sites that can validate the
mapfile, but I've never needed them so I don't have them bookmarked
anywhere. Can anyone on the list make a suggestion to Paul?
-Steve W
On 7/23/2020 12:48 PM, English Paul wrote:
Thanks again Steve – progress:
$ /usr/libexec/mapserv -nh
QUERY_STRING="MAP=wmst?FORMAT=image%2Fpng&LAYERS=winter1km_5min&TRANSPARENT=TRUE&SERVICE=WMS&VERSION=1.1.1&REQUEST=GetMap&STYLES=&TIME=2020-07-23T16%3A40%3A00Z&SRS=EPSG%3A900913&BBOX=-9392582.0328932,4383204.9527744,-9236038.9989652,4539747.9867024&WIDTH=256&HEIGHT=256"
> junk.png
Gives the following in junk.png:
Content-type: text/html
<HTML>
<HEAD><TITLE>MapServer Message</TITLE></HEAD>
<!-- MapServer version 6.0.1 OUTPUT=GIF OUTPUT=PNG OUTPUT=JPEG
OUTPUT=KML SUPPORTS=PROJ SUPPORTS=AGG SUPPORTS=CAIRO SUPPORTS=FREETYPE S
UPPORTS=ICONV SUPPORTS=FRIBIDI SUPPORTS=WMS_SERVER SUPPORTS=WMS_CLIENT
SUPPORTS=WFS_SERVER SUPPORTS=WFS_CLIENT SUPPORTS=WCS_SERVER SUPP
ORTS=SOS_SERVER SUPPORTS=FASTCGI SUPPORTS=THREADS SUPPORTS=GEOS
INPUT=POSTGIS INPUT=OGR INPUT=GDAL INPUT=SHAPEFILE -->
<BODY BGCOLOR="#FFFFFF">
msLoadMap(): Regular expression error. MS_DEFAULT_MAPFILE_PATTERN
validation failed.
msEvalRegex(): R
*From: *mapserver-users <mapserver-users-boun...@lists.osgeo.org> on
behalf of Stephen Woodbridge <stephenwoodbridg...@gmail.com>
*Date: *Wednesday, July 22, 2020 at 19:53
*To: *"mapserver-users@lists.osgeo.org" <mapserver-users@lists.osgeo.org>
*Subject: *Re: [mapserver-users] Slow and degrading performance with
radar (but not satellite) on mapserver-6.0.1-3_0.el6.x86_64
you need to include in your QUERY_STRING=MAP=....&
it is probably hard coded in the fcgi config.
-Steve W
On 7/22/2020 7:15 PM, English Paul wrote:
So you have a complex historical "mess" and its not clear where
the performance issue is. So you need to divide the problem into
small problems that you can verify are or are not contributing. I
would start with something like this:
Thank you – I would not have thought to try it outside of CGI
entirely!
Take one slow image request and try that as cgi or cli and not
fcgi and turn on debugging.
- copy and rename you mapfile so it doesn't mess with the
production requests
Not a major worry in this case – I’m working in an entirely dev
environment. I did make backup copies though!
- turn on the debugging and send it to stderr in the debug mapfile
- you can manually run that image request from the commandline like:
if mapserv is not in your path you might need to find it and your
the path to it below
mapserv -nh QUERY_STRING="everything after the ? in the original
query" >junk.png 2>error.txt
-nh suppresses headers from being output before the image data
error.txt will be stderr output and should contain the debug messages
I couldn’t quite get there – which this is what I ended up running:
# /usr/libexec/mapserv -nh
QUERY_STRING="FORMAT=image%2Fpng&LAYERS=winter1km_5min&TRANSPARENT=TRUE&SERVICE=WMS&VERSION=1.1.1&REQUEST=GetMap&STYLES=&TIME=2020-07-22T22%3A30%3A00Z&SRS=EPSG%3A900913&BBOX=-11584184.507886,4070118.8849183,-11271098.44003,4383204.9527744&WIDTH=256&HEIGHT=256"
> junk.png 2>error.txt
I first tried it with our current map file(s), and then with
MS_ERRORFILE set to stderr and DEBUG set to 5, in both cases, I
got an empty error.txt, and the following in junk.png:
Content-type: text/html
<HTML>
<HEAD><TITLE>MapServer Message</TITLE></HEAD>
<!-- MapServer version 6.0.1 OUTPUT=GIF OUTPUT=PNG OUTPUT=JPEG
OUTPUT=KML SUPPORTS=PROJ SUPPORTS=AGG SUPPORTS=CAIRO SUPPORTS=FREETYPE
SUPPORTS=ICONV SUPPORTS=FRIBIDI SUPPORTS=WMS_SERVER
SUPPORTS=WMS_CLIENT SUPPORTS=WFS_SERVER SUPPORTS=WFS_CLIENT
SUPPORTS=WCS_SERVER SU
PPORTS=SOS_SERVER SUPPORTS=FASTCGI SUPPORTS=THREADS SUPPORTS=GEOS
INPUT=POSTGIS INPUT=OGR INPUT=GDAL INPUT=SHAPEFILE -->
<BODY BGCOLOR="#FFFFFF">
loadMap(): Web application error. CGI variable "map" is
not set.
</BODY></HTML>
I noticed that if I ran it with just -nh, I get the following:
#/usr/libexec/mapserv -nh
This script can only be used to decode form results and
should be initiated as a CGI process via a httpd server.
So maybe this older version just really doesn’t want to be run on
the CLI? Or maybe I’m messing up the QUERY_STRING, or need to set
the CGI variable to something as the junk.png output suggests?
Thanks again and thanks SO MUCH for the super quick reply!!
Paul
On 7/22/2020 1:47 PM, English Paul wrote:
Hi,
Newbie here, just got a work assignment to look into some
performance issues with mapserver-6.0.1-3_0.el6.x86_64 –
specifically, at one time, it rendered radar images very fast,
then it degraded and seemed to consume a lot more CPU. So –
the EC2 instance side was upgraded significantly – and it
still performs badly and uses a lot of CPU. It also seems to
be getting slowly worse over time (days/months, not
seconds/minutes). I asked this on IRC, but it looks like email
might be a better route.
During all of this, the same mapserver instance renders
satellite images quickly. These seem to be a similar, or in
some cases larger size png to start with, rendered onto the
same final map/size.
So – the obvious answer is that it isn’t using the CPU to
render/re-render, but rather spending it on something else –
I/O most likely – eg: a network request, disk I/O, SQL query?
The previous person working on it tried turning on debug at
various levels – but unfortunately that made it even slower,
making it tricky to answer “what is making it slow when debug
is turned off?”
My first instinct was to try an strace and nothing was
obvious. Next up – a flame graph from strace, and/or trying
dtrace – but my understanding is that dtrace is a little weak
on RHEL/CentOS/Amazon Linux 6.0 **and** I’m not particularly
good at that. Also, we’re using fcgi, so attaching to the
correct process is a bit tricky.
My next instinct was to look at release notes and see if the
current stable has anything fixes/improvements that directly
address this – there aren’t any that are obvious to my eyes,
but you developers have been busy! So many things! Including
some performance fixes and one “significant” performance fix.
Current config file:
AddHandler fcgid-script fcgi
FcgidIPCDir /var/run/mod_fcgid
FcgidProcessTableFile /var/run/mod_fcgid/fcgid_shm
FcgidMaxProcesses 10
FcgidMaxProcessesPerClass 10
FcgidMaxRequestInMem 196608
FcgidInitialEnv PROJ_LIB /usr/share/proj
FcgidInitialEnv LD_LIBRARY_PATH
"/usr/local/lib:/usr/pgsql-9.1/lib"
So – suggestions for my next move? I currently plan to take a
quick swing at building 7.6 for RHEL 6.0, knowing there might
be old libraries and whatnot that make that a non-starter. Of
course – we’ve got other infra running on this same instance,
so upgrading everything is a much bigger task.
Strace flame graph?
Stretch and try dtrace?
A better way to use debug?
Something else I’m missing – eg: differences between the
image types that make them perform so differently?
Thanks,
Paul
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