Profiling Module
Jump to navigation
Jump to search
This XQuery Module contains various functions to test and profile code, and to dump information to standard output.
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 $label may be specified to tag the profiling result.
|
Properties | The function is non-deterministic: evaluation order will be preserved by the compiler. |
Examples |
|
prof:mem
Signatures | prof:mem($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 $label may be specified to tag the profiling result.
|
Properties | The function is non-deterministic: evaluation order will be preserved by the compiler. |
Examples |
|
prof:sleep
Signatures | prof:sleep($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:human
Signatures | prof:human($number as xs:integer) as xs:string
|
Summary | Returns a human-readable representation of the specified $number .
|
Example |
|
prof:dump
Signatures | prof:dump($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:variables
Signatures | prof:variables() as empty-sequence()
|
Summary | Prints a list of all current local and global variable assignments to standard error or, if the GUI is used, to the Info View. As every query is optimized before being evaluated, not all of the original variables may be visible in the output. Moreover, many variables of function calls will disappear because functions are inlined. Function inlining can be turned off by setting the INLINELIMIT option to 0 .
|
Properties | The function is non-deterministic: evaluation order will be preserved by the compiler. |
Examples |
|
prof:current-ms
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
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.
|
Examples | Measures the time of an expression:
let $ns1 := prof:current-ns() return ( (: process to measure :) (1 to 1000000)[. = 0], let $ns2 := prof:current-ns() let $ms := ((($ns2 - $ns1) idiv 10000) div 100) return $ms || ' ms' ) |
prof:void
Signatures | prof:void($value as item()*) as empty-sequence()
|
Summary | Swallows all items of the specified $value and returns an empty sequence. This function is helpful if some code needs to be evaluated and if the actual result is irrelevant.
|
Properties | The function is non-deterministic: evaluation order will be preserved by the compiler. |
Examples |
|
prof:type
Signatures | prof:type($expr as item()*) as item()*
|
Summary | Similar to fn:trace($expr, $msg) , but instead of a user-defined message, it emits the compile-time type and estimated result size of its argument.
|
Changelog
- Version 8.5
- Added:
prof:type
(moved from XQuery Module)
- Version 8.1
- Added:
prof:variables
- Version 7.7
- Added:
prof:void
- Version 7.6
- Added:
prof:human
- Version 7.5
- Added:
prof:dump
,prof:current-ms
,prof:current-ns
This module was introduced with Version 7.3.