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Hello, I would like to draw your attention to an xrootd utility that can be helpful in testing/diagnosing xrootd-related problems in qserv. Have a look at "xrd". You can think of it as a command-line tool that speaks the xrootd protocol. It supports several commands and using it is generally far easier than writing code that links to xrootd client libraries and wondering whether you're doing it right. Example: ---------- [danielw@lsst-dbdev2 xrdbuild]$ src/xrd (C) 2004-2010 by the Xrootd group. Xrootd version: v20150319-d2df123 Welcome to the xrootd command line interface. Type 'help' for a list of available commands. > locateall /chk/qservTest_case01_qserv Not connected to any server. > connect lsst-dbdev2:1094 root://lsst-dbdev2.ncsa.illinois.edu:1094//> locateall /chk/qservTest_case01_qserv No matching files were found. root://lsst-dbdev2.ncsa.illinois.edu:1094//> locateall /chk/qservTest_case01_qserv/6630 ------------- Location #1 InfoType: kXrdcLocDataServer CanWrite: true Location: '141.142.237.34:1099' root://lsst-dbdev2.ncsa.illinois.edu:1094//> locateall /chk/qservTest_case01_qserv/6639123 No matching files were found. root://lsst-dbdev2.ncsa.illinois.edu:1094//> Goodbye. [danielw@lsst-dbdev2 xrdbuild]$ ---------- Note that when you connect, you should always connect to the xrootd daemon, because there is no client protocol for the cmsd. Still, you can use this to connect to xrootd daemons to see what they know. I think you can use it to perform the sort of cold-start precaching that would speed up the first queries on a cluster whose redirector has just been restarted. We could probably use a similar command-line tool that, say, could issue queries as a sort of one-shot czar without bringing the czar up and down. So, when you get chunk missing errors, or weird error messages, point this at the cluster and see what happens. Unfortunately, there isn't any such command-line tool for XrdSsi (though I think a simple one could be made: push a stream of bytes to a server addressed by a path, and dump everything that comes back). Good luck, -Daniel ######################################################################## Use REPLY-ALL to reply to list To unsubscribe from the QSERV-L list, click the following link: https://listserv.slac.stanford.edu/cgi-bin/wa?SUBED1=QSERV-L&A=1