Vladimir Steshin created IGNITE-13012:
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Summary: Make node connection checking rely on the configuration.
Simplify node ping routine.
Key: IGNITE-13012
URL: https://issues.apache.org/jira/browse/IGNITE-13012
Project: Ignite
Issue Type: Improvement
Reporter: Vladimir Steshin
Assignee: Vladimir Steshin
Current noted-to-node connection checking has several drawbacks:
1) Minimal connection checking interval is not bound to failure detection
parameters:
static int ServerImpls.CON_CHECK_INTERVAL = 500;
2) Connection checking is made as ability of periodical message sending
(TcpDiscoveryConnectionCheckMessage). It is bound to own time (ServerImpl.
RingMessageWorker.lastTimeConnCheckMsgSent), not to common time of last sent
message. This is weird because any discovery message actually checks
connection. And TpDiscoveryConnectionCheckMessage is just an addition when
message queue is empty for a long time.
3) Period of Node-to-Node connection checking can be sometimes shortened
for strange reason: if no sent or received message appears within
failureDetectionTimeout. Here, despite we have minimal period of connection
checking (ServerImpls.CON_CHECK_INTERVAL), we can also send
TpDiscoveryConnectionCheckMessage before this period exhausted. Moreover, this
premature node ping relies also on time of last received message. Imagine: if
node 2 receives no message from node 1 within some time it decides to do extra
ping node 3 not waiting for regular ping interval. Such behavior makes
confusion and gives no additional guaranties.
4) If #3 happens, node writes in the log on INFO: “Local node seems to be
disconnected from topology …” whereas it is not actually disconnected. User can
see this message if he typed failureDetectionTimeout < 500ms. I wouldn’t like
seeing INFO in a log saying a node is might be disconnected. This sounds like
some troubles raised in network. But not as everything is OK.
Suggestions:
1) Make connection check interval be based on failureDetectionTimeout or
similar params.
2) Make connection check interval rely on common time of last sent
message. Not on dedicated time.
3) Remove additional, random, quickened connection checking.
4) Do not worry user with “Node disconnected” when everything is OK.
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