CHI::Stats(3) User Contributed Perl Documentation CHI::Stats(3)NAMECHI::Stats - Record and report per-namespace cache statistics
VERSION
version 0.55
SYNOPSIS
# Turn on statistics collection
CHI->stats->enable();
# Perform cache operations
# Flush statistics to logs
CHI->stats->flush();
...
# Parse logged statistics
my $results = CHI->stats->parse_stats_logs($file1, ...);
DESCRIPTION
CHI can record statistics, such as number of hits, misses and sets, on
a per-namespace basis and log the results to your Log::Any logger. You
can then parse the logs to get a combined summary.
A single CHI::Stats object is maintained for each CHI root class, and
tallies statistics over any number of CHI::Driver objects.
Statistics are reported when you call the "flush" method. You can
choose to do this once at process end, or on a periodic basis.
METHODS
enable, disable, enabled
Enable, disable, and query the current enabled status.
When stats are enabled, each new cache object will collect
statistics. Enabling and disabling does not affect existing cache
objects. e.g.
my $cache1 = CHI->new(...);
CHI->stats->enable();
# $cache1 will not collect statistics
my $cache2 = CHI->new(...);
CHI->stats->disable();
# $cache2 will continue to collect statistics
flush
Log all statistics to Log::Any (at Info level in the CHI::Stats
category), then clear statistics from memory. There is one log
message for each distinct triplet of root class, cache label, and
namespace. Each log message contains the string "CHI stats:"
followed by a JSON encoded hash of statistics. e.g.
CHI stats: {"absent_misses":1,"label":"File","end_time":1338410398,
"get_time_ms":5,"namespace":"Foo","root_class":"CHI",
"set_key_size":6,"set_time_ms":23,"set_value_size":20,"sets":1,
"start_time":1338409391}
parse_stats_logs
Accepts one or more stats log files as parameters. Parses the logs
and returns a listref of stats hashes by root class, cache label,
and namespace. e.g.
[
{
root_class => 'CHI',
label => 'File',
namespace => 'Foo',
absent_misses => 100,
avg_compute_time_ms => 23,
...
},
{
root_class => 'CHI',
label => 'File',
namespace => 'Bar',
...
},
]
Lines with the same root class, cache label, and namespace are
summed together. Non-stats lines are ignored. The parser will
ignore anything on the line before the "CHI stats:" string, e.g. a
timestamp.
Each parameter to this method may be a filename or a reference to
an open filehandle.
STATISTICS
The following statistics are tracked in the logs:
· "absent_misses" - Number of gets that failed due to item not being
in the cache
· "compute_time_ms" - Total time spent computing missed results in
compute, in ms (divide by number of computes to get average). i.e.
the amount of time spent in the code reference passed as the third
argument to compute().
· "computes" - Number of compute calls
· "expired_misses" - Number of gets that failed due to item expiring
· "get_errors" - Number of caught runtime errors during gets
· "get_time_ms" - Total time spent in get operation, in ms (divide by
number of gets to get average)
· "hits" - Number of gets that succeeded
· "set_key_size" - Number of bytes in set keys (divide by number of
sets to get average)
· "set_value_size" - Number of bytes in set values (divide by number
of sets to get average)
· "set_time_ms" - Total time spent in set operation, in ms (divide by
number of sets to get average)
· "sets" - Number of sets
· "set_errors" - Number of caught runtime errors during sets
The following additional derived/aggregate statistics are computed by
parse_stats_logs:
· "misses" - "absent_misses" + "expired_misses"
· "gets" - "hits" + "misses"
· "avg_compute_time_ms" - "compute_time_ms" / "computes"
· "avg_get_time_ms" - "get_time_ms" / "gets"
· "avg_set_time_ms" - "set_time_ms" / "sets"
· "avg_set_key_size" - "set_key_size" / "sets"
· "avg_set_value_size" - "set_value_size" / "sets"
· "hit_rate" - "hits" / "gets"
SEE ALSO
CHI
AUTHOR
Jonathan Swartz <swartz@pobox.com>
COPYRIGHT AND LICENSE
This software is copyright (c) 2011 by Jonathan Swartz.
This is free software; you can redistribute it and/or modify it under
the same terms as the Perl 5 programming language system itself.
perl v5.14.2 2012-07-04 CHI::Stats(3)
