CPROF - Conditional Profiling for MarkLogic Server
You have written an application or a service using MarkLogic Server
and XQuery or XSLT. Your application uses some combination of
You have discovered a slow request, and you want to profile it.
But adding profiler support to an HTTP request can be tricky.
Changing metaprogramming calls like
is also tricky: the functions from the
return a sequence of the ordinary results, followed by a profile.
This breaks your existing code.
What you want is a way to profile your main request, and stack up nested evaluation profiles until the end of the query. Then you can decide what to do with all the profiler output: display it, log it, email it, etc.
This XQuery library makes that pattern easy. Here is an example:
import module namespace cprof="com.blakeley.cprof" at "/path/to/cprof.xqy"; (: logic to enable profiling :) if (xs:boolean(xdmp:get-request-field('profile', '0'))) then cprof:enable() else (), cprof:value('xdmp:sleep(5)'), (: send the report XML wherever you like :) cprof:report()
The only necessary logic is whether or not to call
After that, you can simply replace
The function signatures are identical.
At the end of the query, call
and do whatever you like with the sequence of
If you get back the empty sequence, then profiling was not enabled.
cprof:report takes an optional boolean argument.
If set, the return value will be a single
with the main request's
prof:metadata element and with
all of the histograms merged into one
This may be a little confusing, since the sum of
all the histogram expressions may exceed headline elapsed time.
You may you have trouble invoking a module using a relative path,
because cprof will call
xdmp:invoke from its location
instead of the caller's location. To work around this,
use an absolute path. This also applies to
The functions in this library are lightweight, so you do not need to disable them for production.
The cprof test cases use XQUT. If you find problems, please provide a test case. Patches are welcome.
Copyright (c) 2011-2014 Michael Blakeley. All Rights Reserved.
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