thevar1able/ClickHouse
1
0
Fork 0
mirror of https://github.com/ClickHouse/ClickHouse.git synced 2024-09-20 16:50:48 +00:00
Code Issues Packages Projects Releases Wiki Activity

Prevent hedged connections overlaps

Browse Source 
Some replicas may be in the establishing state, this means that hedged
connection is waiting for TablesStatusResponse, and if the connection
will not be canceled, then next user of the connection will get
TablesStatusResponse, while this is not the expected package, and you
will see:

    DB::Exception: Received from localhost:9000. DB::Exception: Received from ch-1:9000. DB::Exception: Unknown packet 9 from server ch-2:9000: While executing Remote. Stack trace:

Fix this by disconnecting connection to such replicas, note that this
should be fine in general, since they are "slow" anyway (you may wish
configure hedged requests settings to increase timeouts and similar).
This commit is contained in:
Azat Khuzhin 2021-03-20 18:40:00 +03:00
parent 95c87d4ded
commit 17eaddc3ab
1 changed files with 10 additions and 0 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

10
src/Client/HedgedConnectionsFactory.cpp
View File

@ -38,6 +38,16 @@ HedgedConnectionsFactory::HedgedConnectionsFactory(
HedgedConnectionsFactory::~HedgedConnectionsFactory()
{
/// Stop anything that maybe in progress,
/// to avoid interfer with the subsequent connections.
///
/// I.e. some replcas may be in the establishing state,
/// this means that hedged connection is waiting for TablesStatusResponse,
/// and if the connection will not be canceled,
/// then next user of the connection will get TablesStatusResponse,
/// while this is not the expected package.
stopChoosingReplicas();
pool->updateSharedError(shuffled_pools);
}