Wrap string registers to avoid propagating null bytes, helps #736#737
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Gnarfoz wants to merge 5 commits into
Open
Wrap string registers to avoid propagating null bytes, helps #736#737Gnarfoz wants to merge 5 commits into
Gnarfoz wants to merge 5 commits into
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Add warning to installation guide to exclude the raw entities from recorder if using PostgreSQL as a database backend
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As described in #736, reading the various Modbus version registers leaves some of the resulting sensors with trailing null bytes, if the string doesn't take up the full length of the registers.
This is bad because Home Assistant's recorder mechanism will try to persist these values including the null bytes. If someone is using a database backend that does not support this (like PostgreSQL), this will break recorder for them, system-wide. Recorder updates are batched, and if a batch includes an update to one of these sensors, it is effectively poisoned and will never be stored to the database.
Apart from changing the Modbus integration to provide an option to trim trailing null bytes (or do it unconditionally), wrapping the sensors in templates that do it and excluding the raw sensors from the recorder config seems like the lowest impact change to improve the situation.
I've added a warning to the installation documentation to point this out.