s.partitions can be changed when new partition is registered or when old partition is dropped.
This could lead to data races and panics when s.partitions slice is accessed by concurrently executed queries.
The fix is to make a copy of the selected partitions under s.partitionsLock before performing the query.
(cherry picked from commit b4b79a4961)
Previously only logs inside the selected time range could be returned by stream_context pipe.
For example, the following query could return up to 10 surrounding logs only for the last 5 minutes,
while most users expect this query should return up to 10 surrounding logs without restrictions on the time range.
_time:5m panic | stream_context before 10
This enables the ability to implement stream context feature at VictoriaLogs web UI: https://github.com/VictoriaMetrics/VictoriaMetrics/issues/7063 .
Reduce memory usage when returning stream context over big log streams with millions of entries.
The new logic scans over all the log messages for the selected log stream, while keeping in memory only
the given number of surrounding logs. Previously all the logs for the given log stream on the selected time range
were loaded in memory before selecting the needed surrounding logs.
This should help https://github.com/VictoriaMetrics/VictoriaMetrics/issues/6730 .
Reduce the scan performance for big log streams by fetching only the requested fields. For example, the following
query should be executed much faster than before if logs contain many fields other than _stream, _msg and _time:
panic | stream_context after 30 | fields _stream, _msg, _time
- 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
