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| ==prof:track== | | ==prof:track== |
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| + | {{Mark|Updated with Version 9.2:}} Decimal timing results; by default no memory profiling. |
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| {| width='100%' | | {| width='100%' |
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| | '''Summary''' | | | '''Summary''' |
| |Measures the execution time and memory consumption required for evaluating the specified {{Code|$expression}} and returns a map with the results. The following {{Code|$options}} are available: | | |Measures the execution time and memory consumption required for evaluating the specified {{Code|$expression}} and returns a map with the results. The following {{Code|$options}} are available: |
− | * {{Code|memory}}: Include memory consumption in result (unit: bytes; default: true). | + | * {{Code|time}}: Include execution time in result as {{Code|xs:decimal}} (unit: milliseconds; default: true). |
− | * {{Code|time}}: Include execution time in result (unit: milliseconds; default: true). | + | * {{Code|memory}}: Include memory consumption in result as {{Code|xs:integer}} (unit: bytes; default: false). |
| * {{Code|value}}: Include value in result (default: true). | | * {{Code|value}}: Include value in result (default: true). |
| Helpful notes: | | Helpful notes: |
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| * Added: [[#prof:gc|prof:gc]], [[#prof:runtime|prof:runtime]] | | * Added: [[#prof:gc|prof:gc]], [[#prof:runtime|prof:runtime]] |
| + | * Updated: [[#prof:track|prof:track]]: decimal timing results; by default no memory profiling |
| | | |
| ;Version 9.0 | | ;Version 9.0 |
Revision as of 13:40, 16 April 2019
This XQuery Module contains various functions to test and profile code, and to dump information to standard output.
Conventions
All functions and errors in this module are assigned to the http://basex.org/modules/prof
namespace, which is statically bound to the prof
prefix.
Performance Functions
prof:track
Template:Mark Decimal timing results; by default no memory profiling.
Signatures
|
prof:track($expression as item()) as item()*
prof:track($expression as item(), $options as map(*)?) as item()*
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Summary
|
Measures the execution time and memory consumption required for evaluating the specified $expression and returns a map with the results. The following $options are available:
time : Include execution time in result as xs:decimal (unit: milliseconds; default: true).
memory : Include memory consumption in result as xs:integer (unit: bytes; default: false).
value : Include value in result (default: true).
Helpful notes:
- If you are not interested in some of the returned results, you should disable them to save time and memory.
- Profiling might change the execution behavior of your code: An expression that might be executed iteratively will be cached by the profiling function.
- If a value has a compact internal representation, memory consumption will be very low, even if the serialized result may consume much more memory.
- Please note that memory profiling is only approximative, so it can be quite misleading. If the memory option is enabled, main-memory will be garbage-collected before and after evaluation to improve the quality of the measurement.
|
Properties
|
The function is non-deterministic: evaluation order will be preserved by the compiler.
|
Examples
|
- Return a human-readable representation of the memory consumption caused by fetching an XML document (
fetch:xml is used, as fn:doc may already be evaluated at compilation time):
prof:track(fetch:xml('factbook.xml'))?memory
=> prof:human()
- The function call
prof:track((1 to 1000000)[. mod 2 = 0], map { 'time': false() }) will return something similar to:
map {
"memory": 21548400,
"value": (2, 4, 6, 8, 10, ...)
}
|
prof:time
Signatures
|
prof:time($expr as item()) as item()*
prof:time($expr as item(), $label as xs:string) as item()*
|
Summary
|
Measures the time needed to evaluate $expr and outputs a string to standard error or, if the GUI is used, to the Info View. An optional $label may be specified to tag the profiling result. See prof:track for further notes.
|
Properties
|
The function is non-deterministic: evaluation order will be preserved by the compiler.
|
Examples
|
prof:time(prof:sleep(1000)) outputs something similar to 1000.99 ms .
|
prof:memory
Signatures
|
prof:memory($expr as item()) as item()*
prof:memory($expr as item(), $label as xs:string) as item()*
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Summary
|
Measures the memory allocated by evaluating $expr and outputs a string to standard error or, if the GUI is used, to the Info View. An optional $label may be specified to tag the profiling result. See prof:track for further notes.
|
Properties
|
The function is non-deterministic: evaluation order will be preserved by the compiler.
|
Examples
|
prof:memory((1 to 100000) ! <a/>) will output something similar to 5620 kB .
|
prof:current-ms
Signatures
|
prof:current-ms() as xs:integer
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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 and returns different values every time it is called. Its evaluation order will be preserved by the compiler.
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Examples
|
convert:integer-to-dateTime(prof:current-ms()) returns the current miliseconds in the xs:dateTime format.
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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 and 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 $ms || ' ms'
)
|
Debugging Functions
prof:dump
Signatures
|
prof:dump($expr as item()) as empty-sequence()
prof:dump($expr as item(), $label as xs:string) as empty-sequence()
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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.
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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 INLINELIMIT to 0 .
|
Properties
|
The function is non-deterministic: evaluation order will be preserved by the compiler.
|
Examples
|
for $x in 1 to 2 return ($x, prof:variables()) will dump the values of $x to standard error.
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prof:type
Signatures
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prof:type($expr as item()*) as item()*
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Summary
|
Similar to fn:trace($expr, $msg) , but instead of a user-defined message, it emits the compile-time type and estimated result size of its argument.
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prof:gc
Template:Mark
Signatures
|
prof:gc() as empty-sequence()
prof:gc($count as xs:integer) as empty-sequence()
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Summary
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Enforces Java garbage collection. If no $count is supplied, garbage will be collected once. Please note that this function should only be used for debugging purposes; in productive code, it is best to trust the garbage collecting strategies of Java.
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prof:runtime
Template:Mark
Signatures
|
prof:runtime($name of xs:string) as xs:integer
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Summary
|
Returns the value of the specified runtime $option . The following options exist:
max : Maximum memory that the Java virtual machine will attempt to use.
total : Total memory in the Java virtual machine (varies over time).
used : Currently used memory (varies over time, will shrink after garbage collection).
processors : number of processors available to the Java virtual machine.
|
option
|
The specified option is unknown.
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Examples
|
prof:gc(3), prof:human(prof:runtime('used')) performs some garbage collection and returns the currently used amount of memory in a user-friendly format.
|
Helper Functions
prof:void
Signatures
|
prof:void($value as item()*) as empty-sequence()
|
Summary
|
Swallows all items of the specified $value and returns an empty sequence. This function is helpful if some code needs to be evaluated and if the actual result is irrelevant.
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Properties
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The function is non-deterministic: evaluation order will be preserved by the compiler.
|
Examples
|
|
prof:sleep
Signatures
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prof:sleep($ms as xs:integer) as empty-sequence()
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Summary
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Sleeps for the specified number of milliseconds.
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Properties
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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
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Summary
|
Returns a human-readable representation of the specified $number .
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Example
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prof:human(16384) returns 16K .
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Errors
Code
|
Description
|
option
|
The specified option is unknown.
|
Changelog
- Version 9.2
- Version 9.0
- Version 8.5
- Version 8.1
- Version 7.7
- Version 7.6
- Version 7.5
This module was introduced with Version 7.3.