Change the return values for these functions - now they return the unmarshaled result plus
the size of the unmarshaled result in bytes, so the caller could re-slice the src for further unmarshaling.
This improves performance of these functions in hot loops of VictoriaLogs a bit.
- Move uniqueFields from rows to blockStreamMerger struct.
This allows localizing all the references to uniqueFields inside blockStreamMerger.mustWriteBlock(),
which should improve readability and maintainability of the code.
- Remove logging of the event when blocks cannot be merged because they contain more than maxColumnsPerBlock,
since the provided logging didn't provide the solution for the issue with too many columns.
I couldn't figure out the proper solution, which could be helpful for end user,
so decided to remove the logging until we find the solution.
This commit also contains the following additional changes:
- It truncates field names longer than 128 chars during logs ingestion.
This should prevent from ingesting bogus field names.
This also should prevent from too big columnsHeader blocks,
which could negatively affect search query performance,
since columnsHeader is read on every scan of the corresponding data block.
- It limits the maximum length of const column value to 256.
Longer values are stored in an ordinary columns.
This helps limiting the size of columnsHeader blocks
and improving search query performance by avoiding
reading too long const columns on every scan of the corresponding data block.
- It deduplicates columns with identical names during data ingestion
and background merging. Previously it was possible to pass columns with duplicate names
to block.mustInitFromRows(), and they were stored as is in the block.
Updates https://github.com/VictoriaMetrics/VictoriaMetrics/issues/4762
Updates https://github.com/VictoriaMetrics/VictoriaMetrics/pull/4969
