What's the state of the system if you take a thread dump when it's in unresponsive mood?
On 10 November 2014 05:13, Ryan Sattler <[email protected]> wrote: > (I'm posting this question here since it seems a bit too non-specific for > Stack Overflow). > > I've been working on a Neo4j system that needs to ingest a lot of data. > We've been testing the data-load with many writing threads. Generally this > works fine. For example, writing with 5 threads completes normally. Writing > with 10 threads however works fine (in fact ~2x speed) for a while, but > then suddenly every transaction starts timing out, even though CPU usage > was generally less than 50%. > > Also, it doesn't fully recover for a long time if ever. Even minutes after > the load has been completely turned off, Neo still remains unresponsive to > certain kinds of queries - for example, I have a script that runs "MATCH > (a) WITH a LIMIT 10000 OPTIONAL MATCH (a)-[r]-() DELETE a,r RETURN > COUNT(*)" repeatedly which normally works fine when run by itself, but in > this case it keeps timing out even when there are no other queries. I have > to kill and restart the process. Needless to say this behaviour is less > than ideal. I tried adding a "max-execution-time" header of 5 seconds but > this didn't seem to help much if at all. > > In other tests I've seen weird spikes of bad performance 30 mins to a few > hours after one of these meltdowns, in a kind of "echo", even when the load > has been greatly reduced in the meantime (and when normally that load would > sustain good performance indefinitely). > > Any idea what's going on? > > TL;DR: Neo fails abruptly under heavy load and seems slow to recover even > when the load is removed. > > Thanks, > Ryan Sattler > > -- > You received this message because you are subscribed to the Google Groups > "Neo4j" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to [email protected]. > For more options, visit https://groups.google.com/d/optout. > -- You received this message because you are subscribed to the Google Groups "Neo4j" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. For more options, visit https://groups.google.com/d/optout.
