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Bug
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Resolution: Fixed
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Minor
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2.8.10, 2.9.4, 3.0.2
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MOODLE_28_STABLE, MOODLE_29_STABLE, MOODLE_30_STABLE
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MOODLE_29_STABLE, MOODLE_30_STABLE
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If there are temporary problems with the data directory filesystem it is possible to have a "null" cache configuration file generated. This is a valid configuration (in that it contains the correct structures) but it contains no store definitions or mappings. This causes Moodle to use cachestore_dummy.
The scenario that causes this appears to be the file system dropping out momentarily during cache_config::include_configuration(), after the file_exists() check but before the include(), then reappearing in time for the new config file to be written. This seems like an extremely unlikely situation but we have seen this happen on our live system yesterday.
The problem can be simulated using these steps:
- Ensure you have a valid cache configuration file
- Comment out the include($cachefile) line in cache_config::include_configuration()
- Go to a Moodle page. If you have debugging switched on you will see messages about "Your cache configuration file is out of date and needs to be refreshed"
- Look at your cache configuration file. It should now have "unknown" as the site identifier and no stores or mappings set up
- has a non-specific relationship to
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MDL-51111 MUC config.php random reset
- Closed