1CHI::Stats(3) User Contributed Perl Documentation CHI::Stats(3)
2
3
4
6 CHI::Stats - Record and report per-namespace cache statistics
7
9 version 0.60
10
12 # Turn on statistics collection
13 CHI->stats->enable();
14
15 # Perform cache operations
16
17 # Flush statistics to logs
18 CHI->stats->flush();
19
20 ...
21
22 # Parse logged statistics
23 my $results = CHI->stats->parse_stats_logs($file1, ...);
24
26 CHI can record statistics, such as number of hits, misses and sets, on
27 a per-namespace basis and log the results to your Log::Any logger. You
28 can then parse the logs to get a combined summary.
29
30 A single CHI::Stats object is maintained for each CHI root class, and
31 tallies statistics over any number of CHI::Driver objects.
32
33 Statistics are reported when you call the "flush" method. You can
34 choose to do this once at process end, or on a periodic basis.
35
37 enable, disable, enabled
38 Enable, disable, and query the current enabled status.
39
40 When stats are enabled, each new cache object will collect
41 statistics. Enabling and disabling does not affect existing cache
42 objects. e.g.
43
44 my $cache1 = CHI->new(...);
45 CHI->stats->enable();
46 # $cache1 will not collect statistics
47 my $cache2 = CHI->new(...);
48 CHI->stats->disable();
49 # $cache2 will continue to collect statistics
50
51 flush
52 Log all statistics to Log::Any (at Info level in the CHI::Stats
53 category), then clear statistics from memory. There is one log
54 message for each distinct triplet of root class, cache label, and
55 namespace. Each log message contains the string "CHI stats:"
56 followed by a JSON encoded hash of statistics. e.g.
57
58 CHI stats: {"absent_misses":1,"label":"File","end_time":1338410398,
59 "get_time_ms":5,"namespace":"Foo","root_class":"CHI",
60 "set_key_size":6,"set_time_ms":23,"set_value_size":20,"sets":1,
61 "start_time":1338409391}
62
63 parse_stats_logs
64 Accepts one or more stats log files as parameters. Parses the logs
65 and returns a listref of stats hashes by root class, cache label,
66 and namespace. e.g.
67
68 [
69 {
70 root_class => 'CHI',
71 label => 'File',
72 namespace => 'Foo',
73 absent_misses => 100,
74 avg_compute_time_ms => 23,
75 ...
76 },
77 {
78 root_class => 'CHI',
79 label => 'File',
80 namespace => 'Bar',
81 ...
82 },
83 ]
84
85 Lines with the same root class, cache label, and namespace are
86 summed together. Non-stats lines are ignored. The parser will
87 ignore anything on the line before the "CHI stats:" string, e.g. a
88 timestamp.
89
90 Each parameter to this method may be a filename or a reference to
91 an open filehandle.
92
94 The following statistics are tracked in the logs:
95
96 · "absent_misses" - Number of gets that failed due to item not being
97 in the cache
98
99 · "compute_time_ms" - Total time spent computing missed results in
100 compute, in ms (divide by number of computes to get average). i.e.
101 the amount of time spent in the code reference passed as the third
102 argument to compute().
103
104 · "computes" - Number of compute calls
105
106 · "expired_misses" - Number of gets that failed due to item expiring
107
108 · "get_errors" - Number of caught runtime errors during gets
109
110 · "get_time_ms" - Total time spent in get operation, in ms (divide by
111 number of gets to get average)
112
113 · "hits" - Number of gets that succeeded
114
115 · "set_key_size" - Number of bytes in set keys (divide by number of
116 sets to get average)
117
118 · "set_value_size" - Number of bytes in set values (divide by number
119 of sets to get average)
120
121 · "set_time_ms" - Total time spent in set operation, in ms (divide by
122 number of sets to get average)
123
124 · "sets" - Number of sets
125
126 · "set_errors" - Number of caught runtime errors during sets
127
128 The following additional derived/aggregate statistics are computed by
129 parse_stats_logs:
130
131 · "misses" - "absent_misses" + "expired_misses"
132
133 · "gets" - "hits" + "misses"
134
135 · "avg_compute_time_ms" - "compute_time_ms" / "computes"
136
137 · "avg_get_time_ms" - "get_time_ms" / "gets"
138
139 · "avg_set_time_ms" - "set_time_ms" / "sets"
140
141 · "avg_set_key_size" - "set_key_size" / "sets"
142
143 · "avg_set_value_size" - "set_value_size" / "sets"
144
145 · "hit_rate" - "hits" / "gets"
146
148 CHI
149
151 Jonathan Swartz <swartz@pobox.com>
152
154 This software is copyright (c) 2012 by Jonathan Swartz.
155
156 This is free software; you can redistribute it and/or modify it under
157 the same terms as the Perl 5 programming language system itself.
158
159
160
161perl v5.32.0 2020-07-28 CHI::Stats(3)