annotate mod_log_events_by_memory/README.markdown @ 5536:96dec7681af8

mod_firewall: Update user marks to store instantly via map store The original approach was to keep marks in memory only, and persist them at shutdown. That saves I/O, at the cost of potentially losing marks on an unclean shutdown. This change persists marks instantly, which may have some performance overhead but should be more "correct". It also splits the marking/unmarking into an event which may be watched or even fired by other modules.
author Matthew Wild <mwild1@gmail.com>
date Thu, 08 Jun 2023 16:20:42 +0100
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1 This module compares the memory usage reported by Lua before and after
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2 each event and reports it to the log if it exceeds the configuration
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3 setting `log_memory_threshold` (in bytes).
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4
5fe34e5f9829 mod_log_events_by_memory: Log events where Lua memory usage increased
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5 ``` lua
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6 log_memory_threshold = 20*1024
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7 ```
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8
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9 If you are looking to identify memory leaks, please first read [Three
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10 kinds of memory
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11 leaks](https://blog.nelhage.com/post/three-kinds-of-leaks/).
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12
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13 Prosody runs on Lua which uses automatic memory management with garbage
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14 collection, so the numbers reported by this module are very likely to be
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15 useless for the purpose of identifying memory leaks. Large, but
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16 temporary, increases in memory usage can however highlight other kinds
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17 of performance problems and sometimes even provide hits for where to
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18 look for memory leaks.