Difference between revisions of "Profiling Module"

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Revision as of 00:32, 9 September 2012

This XQuery Module contains functions for XQuery code.

Conventions

All functions in this module are assigned to the http://basex.org/modules/prof namespace, which is statically bound to the prof prefix.
All errors are assigned to the http://basex.org/errors namespace, which is statically bound to the bxerr prefix.

Functions

prof:time

Signatures prof:time($expr as item()) as item()*
prof:time($expr as item(), $cache as xs:boolean) as item()*
prof:time($expr as item(), $cache as xs:boolean, $label as xs:string) as item()*
Summary Measures the time needed to evaluate $expr and sends it to standard error or, if the GUI is used, to the Info View.
If $cache is set to true(), the result will be temporarily cached. This way, a potential iterative execution of the expression (which often yields different memory usage) is blocked.
A third, optional argument $label may be specified to tag the profiling result.
Examples
  • prof:time("1 to 100000") may output 25.69 ms.
  • prof:time("1 to 100000", true()) may output 208.12 ms.
Properties The function is non-deterministic: evaluation order will be preserved by the compiler.

prof:mem

Signatures prof:mem($expr as item()) as item()*
prof:mem($expr as item(), $cache as xs:boolean) as item()*
prof:mem($expr as item(), $cache as xs:boolean, $label as xs:string) as item()*
Summary Measures the memory allocated by evaluating $expr and sends it to standard error or, if the GUI is used, to the Info View.
If $cache is set to true(), the result will be temporarily cached. This way, a potential iterative execution of the expression (which often yields different memory usage) is blocked.
A third, optional argument $label may be specified to tag the profiling result.
Examples
  • prof:mb("1 to 100000") may output 0 Bytes.
  • prof:mb("1 to 100000", true()) may output 26.678 mb.
Properties The function is non-deterministic: evaluation order will be preserved by the compiler.

prof:sleep

Signatures prof:sleep($ms as xs:integer) as empty-sequence()*
Summary Sleeps for the specified number of milliseconds.
Properties The function is non-deterministic: evaluation order will be preserved by the compiler.

prof:dump

Template:Mark

Signatures prof:dump($expr as item()) as empty-sequence()
prof:dump($expr as item(), $label as xs:string) as empty-sequence()
Summary Dumps a serialized representation of $expr to STDERR, optionally prefixed with $label, and returns an empty sequence. If the GUI is used, the dumped result is shown in the Info View.
Properties In contrast to fn:trace(), the consumed expression will not be passed on.

prof:current-ms

Template:Mark

Signatures prof:current-ms() as xs:integer
Summary Returns the number of milliseconds passed since 1970/01/01 UTC. The granularity of the value depends on the underlying operating system and may be larger. For example, many operating systems measure time in units of tens of milliseconds.
Properties In contrast to fn:current-time(), the function is non-deterministic, as it returns different values every time it is called. Its evaluation order will be preserved by the compiler.

prof:current-ns

Template:Mark

Signatures prof:current-ns() as xs:integer
Summary Returns the current value of the most precise available system timer in nanoseconds.
Properties In contrast to fn:current-time(), the function is non-deterministic, as it returns different values every time it is called. Its evaluation order will be preserved by the compiler.

Changelog

Version 7.5

This module was introduced with Version 7.3.