These caches aren't expected to grow big, so it is OK to use the most simplest cache based on sync.Map.
The benefit of this cache compared to workingsetcache is better scalability on systems with many CPU cores,
since it doesn't use mutexes at fast path.
An additional benefit is lower memory usage on average, since the size of in-memory cache equals
working set for the last 3 minutes.
The downside is that there is no upper bound for the cache size, so it may grow big during workload spikes.
But this is very unlikely for typical workloads.
Partition directories can be manually deleted and copied from another sources such as backups or other VitoriaLogs instances.
In this case the persisted cache becomes out of sync with partitions. This can result in missing index entries
during data ingestion or in incorrect results during querying. So it is better to do not persist caches.
This shouldn't hurt VictoriaLogs performance just after the restart too much, since its caches usually contain
small amounts of data, which can be quickly re-populated from the persisted data.
Substitute global streamTagsCache with per-blockSearch cache for ((stream.id) -> (_stream value)) entries.
This improves scalability of obtaining _stream values on a machine with many CPU cores, since every CPU
has its own blockSearch instance.
This also should reduce memory usage when querying logs over big number of streams, since per-blockSearch
cache of ((stream.id) -> (_stream value)) entries is limited in size, and its lifetime is bounded by a single query.
This should smooth CPU and RAM usage spikes related to these periodic tasks,
by reducing the probability that multiple concurrent periodic tasks are performed at the same time.
- Compare the actual free disk space to the value provided via -storage.minFreeDiskSpaceBytes
directly inside the Storage.IsReadOnly(). This should work fast in most cases.
This simplifies the logic at lib/storage.
- Do not take into account -storage.minFreeDiskSpaceBytes during background merges, since
it results in uncontrolled growth of small parts when the free disk space approaches -storage.minFreeDiskSpaceBytes.
The background merge logic uses another mechanism for determining whether there is enough
disk space for the merge - it reserves the needed disk space before the merge
and releases it after the merge. This prevents from out of disk space errors during background merge.
- Properly handle corner cases for flushing in-memory data to disk when the storage
enters read-only mode. This is better than losing the in-memory data.
- Return back Storage.MustAddRows() instead of Storage.AddRows(),
since the only case when AddRows() can return error is when the storage is in read-only mode.
This case must be handled by the caller by calling Storage.IsReadOnly()
before adding rows to the storage.
This simplifies the code a bit, since the caller of Storage.MustAddRows() shouldn't handle
errors returned by Storage.AddRows().
- Properly store parsed logs to Storage if parts of the request contain invalid log lines.
Previously the parsed logs could be lost in this case.
Updates https://github.com/VictoriaMetrics/VictoriaMetrics/issues/4737
Updates https://github.com/VictoriaMetrics/VictoriaMetrics/pull/4945
* lib/logstorage: switch to read-only mode when running out of disk space
Added support of `--storage.minFreeDiskSpaceBytes` command-line flag to allow graceful handling of running out of disk space at `--storageDataPath`.
See: https://github.com/VictoriaMetrics/VictoriaMetrics/issues/4737
Signed-off-by: Zakhar Bessarab <z.bessarab@victoriametrics.com>
* lib/logstorage: fix error handling logic during merge
Signed-off-by: Zakhar Bessarab <z.bessarab@victoriametrics.com>
* lib/logstorage: fix log level
Signed-off-by: Zakhar Bessarab <z.bessarab@victoriametrics.com>
---------
Signed-off-by: Zakhar Bessarab <z.bessarab@victoriametrics.com>
Co-authored-by: Nikolay <nik@victoriametrics.com>
The previous code could result in the following data race:
1. The s.ptwHot partition is marked to be deleted
2. ptw.decRef() is called on it
3. ptw.pt is set to nil
4. s.ptwHot.pt is accessed from concurrent goroutine, which leads to panic.
The change clears s.ptwHot under s.partitionsLock in order to prevent from the data race.
This is a follow-up for 8d50032dd6
Updates https://github.com/VictoriaMetrics/VictoriaMetrics/issues/4895
