Empty fields are treated as non-existing fields by VictoriaLogs data model.
So there is no sense in returning empty fields in query results, since they may mislead and confuse users.
Previously the original timestamp was used in the copied query, so _time:duration filters
were applied to the original time range: (timestamp-duration ... timestamp]. This resulted
in stopped live tailing, since new logs have timestamps bigger than the original time range.
Updates https://github.com/VictoriaMetrics/VictoriaMetrics/issues/7028
Previously the query could return incorrect results, since the query timestamp was updated with every Query.Clone() call
during iterative search for the time range with up to limit=N rows.
While at it, optimize queries, which find low number of matching logs, while spend a lot of CPU time for searching
across big number of logs. The optimization reduces the upper bound of the time range to search if the current time range
contains zero matching rows.
Updates https://github.com/VictoriaMetrics/VictoriaMetrics/issues/6785
- Consistently return the first `limit` log entries if the total size of found log entries doesn't exceed 1Mb.
See app/vlselect/logsql/sort_writer.go . Previously random log entries could be returned with each request.
- Document the change at docs/VictoriaLogs/CHANGELOG.md
- Document the `limit` query arg at docs/VictoriaLogs/querying/README.md
- Make the change less intrusive.
Updates https://github.com/VictoriaMetrics/VictoriaMetrics/issues/5674
Updates https://github.com/VictoriaMetrics/VictoriaMetrics/pull/5778
This reverts commit c19048dc13.
Reason for revert: it has been appeared that the net/http.ResponseWriter is already buffered,
so there in no need in double bufferring
