Sync Errors

colmfield

Hi,

In the logs i see a lot of (hundreds) "Sync errors", what are these caused by? They seem to be generated by a small subset of users (20 out of 200), but one or two of them are causing most of them.

20-Sep-10 03:49:21,684 |INFO |LightstreamerLogger.requests     |SERVER POOLED THREAD 10    |Sync error: Can't find session from XXX.XXX.XXX.XXX:1603

Cheers,
Colm

Dario Crivelli

This post might, in part, be the answer to your other post.
The "sync errors" may be caused by an overload on the client host.
When the "sync errors" affect rebind requests (possibly long polling requests) the client recovers by opening a new session.
Still, watching a longer log snippet might help classifying the case.

Dario Crivelli

As you say in the other post that the occurrences of the "sync error" seem to be unrelated with the observed reconnections,
we still need a suitable log snippet to analyze the case.
By the way, are the affected clients the same ones affected by reconnections or even these subsets are unrelated?

A "sync error" means that a client is performing a request related with a session which is not currently open in the Server.
The main causes are:
- the request reaches the wrong Server instance, in a clustering scenario with incorrect configuration;
- the request reaches the Server with a delay and in the meantime the session has been closed.
Since you see the error only on a subset of your clients, the latter case might be the most likely. Do you have notice of any CPU or network issues on some clients?