Add 3 new engine arguments:
- flush_time
- flush_rows
- flush_bytes
That will be checked only for background flush, this maybe useful if
INSERT latency is "crucial".
Add two new settings for the Distributed engine:
- bytes_to_delay_insert
- max_delay_to_insert
If at the beginning of INSERT there will be too much pending data, more
then bytes_to_delay_insert, then the INSERT will wait until it will be
shrinked, and not more then max_delay_to_insert seconds.
If after this there will be still too much pending, it will throw an
exception.
Also new profile events were added (by analogy to the MergeTree):
- DistributedDelayedInserts (although you can use system.errors instead
of this, but still)
- DistributedRejectedInserts
- DistributedDelayedInsertsMilliseconds
Right now with distributed_directory_monitor_batch_inserts=1 and
insert_distributed_sync=0 INSERT into Distributed table will store
blocks that should be sent to remote (and in case of
prefer_localhost_replica=0 to the localhost too) on the local
filesystem, and sent it in background.
However there is no limit for this storage, and if the remote is
unavailable (or some other error), these pending blocks may take
significant space, and this is not always desired behaviour.
Add new Distributed setting - bytes_to_throw_insert, that will set the
limit for how much pending bytes is allowed, if the limit will be
reached an exception will be throw.
By default was set to 0, to avoid surprises.
Two new settings (by analogy with MergeTree family) has been added:
- `fsync_after_insert` - Do fsync for every inserted. Will decreases
performance of inserts.
- `fsync_tmp_directory` - Do fsync for temporary directory (that is used
for async INSERT only) after all part operations (writes, renames,
etc.).
Refs: #17380 (p1)
Add inter-server cluster secret, it is used for Distributed queries
inside cluster, you can configure in the configuration file:
<remote_servers>
<logs>
<shard>
<secret>foobar</secret> <!-- empty -- works as before -->
...
</shard>
</logs>
</remote_servers>
And this will allow clickhouse to make sure that the query was not
faked, and was issued from the node that knows the secret. And since
trust appeared it can use initial_user for query execution, this will
apply correct *_for_user (since with inter-server secret enabled, the
query will be executed from the same user on the shards as on initator,
unlike "default" user w/o it).
v2: Change user to the initial_user for Distributed queries if secret match
v3: Add Protocol::Cluster package
v4: Drop Protocol::Cluster and use plain Protocol::Hello + user marker
v5: Do not use user from Hello for cluster-secure (superfluous)
