I'd like to set a query timeout in neo4j.conf for Neo4j 3.0.1. Any query taking longer than the timeout should get killed. I'm primarily concerned with setting the timeout for queries originating from the Neo4j Browser.
It looks like this was possible in the past with:
execution_guard_enabled=true
org.neo4j.server.webserver.limit.executiontime=20000
However, this old method doesn't work for me. I see Neo4j 3.0 has a dbms.transaction_timeout option defined as a "timeout for idle transactions". However, this setting also doesn't seem to do the trick.
Thanks to #stdob for the comment explaining a solution.
In Neo4j 3.0.1 Community, I verified that the following addition to neo4j.conf enabled a query timeout of 1 second for Browser queries:
unsupported.dbms.executiontime_limit.enabled=true
unsupported.dbms.executiontime_limit.time=1s
I did not check whether the timeout applies to queries oustide of Neo4j Browser, but I assume so. I did find some documentation in the Neo4j codebase for unsupported.dbms.executiontime_limit.time:
If execution time limiting is enabled in the database, this configures the maximum request execution time.
I believe dbms.transaction.timeout is the current way of limiting execution time
Related
Using Neo4j 4.4.11 (community edition), I'm trying to delete a certain type of relationships from my graph with cypher-shell:
MATCH ()-[r:MYRELATIONSHIPLABEL]->() CALL { WITH r DETACH DELETE r } IN TRANSACTIONS OF 10000 ROWS;
But I always end up with this error:
Connection read timed out due to it taking longer than the server-supplied timeout value via configuration hint.
Is it possible to increase the read timeout directly in cypher-shell without changing the server settings? (I did not find anything in the docs.)
Yes, that is possible by using the following command.
call dbms.setConfigValue('dbms.transaction.timeout','0')
The zero indicates that there should be no timeout. As indicated by Christophe in the comments, this call changes the server setting via cypher shell, so all the applications connecting to Neo4j are affected. There is no way around this other than to change it back to the original setting once you are done.
I'm using Neo4j 3.5.14 Enterprise (cypher over http/bolt). I'm seeing an issue where randomly a cypher query would be stuck never to be back again which takes out a worker thread. Eventually, if the service is not redeployed, all worker threads would be stuck and the service is no longer doing its job.
I tried using apoc.cypher.runTimeboxed but that appears to cause my queries to not return until the time limit is over (20000 ms in this case) even though in some cases it can return faster than that. I'm actually not sure that runTimeboxed would work because I believe it is actually stuck forever which might not respond to time limit anyway depending on how that's implemented.
My question is - how would you end a runaway query like that? Any tricks?
I am using 0.98.1 version of HBase server and client. My application has strict response time requirements. As far as HBase is concerned, I would like to abort the HBase operation if the execution exceeds 1 or 2 seconds. This task timeout is useful in case of Region-Server being non-responsive or has crashed.
I tired configuring
1) HBASE_RPC_TIMEOUT_KEY = "hbase.rpc.timeout";
2) HBASE_CLIENT_RETRIES_NUMBER = "hbase.client.retries.number";
However, the Put operations never timeout (I am using sync flush). The operations return only after the Put is successful.
I looked through the code and found that the function receiveGlobalFailure in AsyncProcess class keeps resubmitting the task without any check on the retires. This is in version 0.98.1
I do see that in 0.99.1 there have been some changes to AsyncProcess class that might do what I want. I have not verified it though.
My questions are:
Is there any other configuration that I missed that can give me
the desired functionality.
Do I have to use 0.99.1 client to
solve my problem? Does 0.99.1 solve my problem?
If I have to use 0.99.1 client, then do I have to use 0.99.1 server or can I still use my existing 0.98.1 region-server.
Whenever I try to run cypher queries in Neo4j browser 2.0 on large (anywhere from 3 to 10GB) batch-imported datasets, I receive an "Unknown Error." Then Neo4j server stops responding, and I need to exit out using Task Manager. Prior to this operation, the server shuts down quickly and easily. I have no such issues with smaller batch-imported datasets.
I work on a Win 7 64bit computer, using the Neo4j browser. I have adjusted the .properties file to allow for much larger memory allocations. I have configured my JVM heap to 12g, which should be fine for 64bit JDK. I just recently doubled my RAM, which I thought would fix the issue.
My CPU usage is pegged. I have the logs enabled but I don't know where to find them.
I really like the visualization capabilities of the 2.0.4 browser, does anyone know what might be going wrong?
Your query is taking a long time, and the web browser interface reports "Unknown Error" after a certain timeout period. The query is still running, but you won't see the results in the browser. This drove me nuts too when it first happened to me. If you run the query in the neo4j shell you can verify whether or not this is the problem, because the shell won't time out.
Once this timeout occurs, you can find that the whole system becomes quite non-responsive, especially if you re-run the query, because now you have two extremely long queries running in parallel!
Depending on the type of query, you may be able to improve performance. Sometimes it's as simple as limiting the number of returned nodes (in cases where you only need to find one node or path).
Hope this helps.
Grace and peace,
Jim
How do set - in my case raise - the connection timeouts of the Neo4j server? I have a server extension to which I POST data, sometimes that much that the extension is running for a couple of minutes. But after 200 seconds, the connection is dropped by the server. I think I have to raise the max idle time of the embedded jetty - but I don't know how to do that since it's all configured within the Neo4j Server code.
Edit: I've tried both Neo4j 1.8.2 and 1.9.RC2 with the same result.
Edit2: Added the "embedded-jetty" tag because there are no answers until now; perhaps the question can be answered by someone with knowledge about embedded Jetty since Neo4j uses an embedded Jetty.
Thank you!
I still don't know if there is a solution in the Neo4j server with versions <2.0. However, with switching to 2.0.0 and above, this issue was gone for my case.
The server guards against orphaned transactions by using a timeout. If there are no requests for a given transaction within the timeout period, the server will roll it back. You can configure the timeout period by setting the following property to the number of seconds before timeout. The default timeout is 60 seconds.
org.neo4j.server.transaction.timeout=60
See http://docs.neo4j.org/chunked/stable/server-configuration.html