Reduce size of archive tables BLOB: use proper PHP ini 'serialize_precision=-1'

rrit · March 30, 2025, 7:41pm

If the archive table size is huge, check the PHP ini setting serialize_precision.
This defaults to serialize_precision=-1 since PHP 7.1 - and should not be changed.

If changed the BLOBs in the archive tables become huge.

E.g. serialize_precision=100 results in:

php -r 'echo serialize((float)0.402);
'd:0.40200000000000002398081733190338127315044403076171875;

Also see:

github.com/matomo-org/matomo

Implement check if php `serialize_precision` is properly set to prevent huge `matomo_archive_blob`-tables

ouvert 07:17PM - 30 Mar 25 UTC

rr-it

Enhancement To Triage

## Summary The php `serialize_precision` ini setting directly influences the BLO…B size and thereby the size of `matomo_archive_blob`-tables. E.g. `serialize_precision=100` results in: ```bash php -r 'echo serialize((float)0.402);' d:0.40200000000000002398081733190338127315044403076171875; ``` With a setting like this the `matomo_archive_blob`-tables really become very huge. Default setting `serialize_precision=-1` results in: ```bash php -r 'echo serialize((float)0.402);' d:0.402; ``` Also see: https://www.php.net/manual/en/ini.core.php#ini.serialize-precision Since PHP 7.1 the default is `serialize_precision=-1`. > -1 means that an enhanced algorithm for rounding such numbers will be used. For PHP versions < 7.1 the default is `serialize_precision=17` . ## Your Environment * Matomo Version: * PHP Version: * Server Operating System: * Additionally installed plugins: