In this case error_count can be decreased before checking it for
rescheduling send.
And actually this can be a problem not only when
distributed_directory_monitor_{max_,}sleep_time_ms > 5min, because all
threads can be occupated and the real timeout between sends will be > 5min.
1. Moved Volume to separate file
2. Created IVolume interface and implemented current behaviour in implementation of new interface — VolumeJBOD
3. Replaced all old volume usages with new VolumeJBOD. Where it is unnecessary to have JBOD — left just IVolume.
4. Removed old Volume completely
5. Moved StoragePolicy to separated files
6. Moved DiskSelector to separated files
7. Removed DiskSpaceMonitor file
This also fixes hardlink code (when one file should be sent to multiple
servers, i.e. internal_replication == false) of writeToShard() with
distributed_storage_policy (i.e. when StorageDistributed::getPath() will
path to different filesystems).
Plus also cleanup DistributedBlockOutputStream::writeToShard() a little.
Since in this case it will be scheduled from the
DistributedBlockOutputStream with the
distributed_directory_monitor_max_sleep_time_ms, and this will overwrite
timer that was set by the DistributedBlockOutputStream, not good.
Before this patch each INSERT query re-schedule distributed send, thus
each time it resets the timer, while this is not the expected behaviour,
since in on frequent INSERT distributed sends will not be triggered at
all.
Fix this by not resetting the timer.
After #8756 the problem with 1 thread for each (distributed table, disk)
for distributed sends became even worse (since there can be multiple
disks), so use predefined thread pool for this tasks, that can be
controlled with background_distributed_schedule_pool_size knob.
Add missing conversion (via ConvertingBlockInputStream) for INSERT into
remote nodes (for sync insert, async insert and async batch insert),
like for local nodes (in DistributedBlockOutputStream::writeBlockConverted).
This is required when the structure of the Distributed table differs
from the structure of the local table.
And also add a warning message, to highlight this in logs (since this
works slower).
Fixes: #19888
