Is there any chance that I'm seeing a side effect of issue #3786
<https://github.com/orientechnologies/orientdb/issues/3786>, which is fixed
in version 2.0.6? It *does* occur during an UPSERT, after which I am adding
one or more edges.
The issue is described as, "*In case of concurrency, the
OConcurrentModificationException should be caught and managed properly by
applying changes on loaded record.*"
Thanks,
Patrick
On Tuesday, March 31, 2015 at 11:16:53 AM UTC-6, Patrick Hoeffel wrote:
>
> Colin,
>
> It's only running on a single thread right now, so everything is running
> serially and synchronously. The idea is that I get a JSON data document
> from a relational database (SQL Server), and that record has a number of FK
> values as fields.
>
> 1. Insert/Update the main record
> 2. Iterate over the FK fields. For each FK:
> a. Does the destination Class exist?
> If (yes) then does the Edge class exist?
> If (yes) then does the actual vertex instance of the
> destination class exist?
> If (no) then create vertex for destination end of the edge
> I'm about to create
> Does the instance of the Edge already exist?
> If (no) then "CREATE EDGE RELATIONSHIP FROM (srcVertex)
> TO (destVertex)"
> return;
>
> The deadlock is occurring on the main record, interestingly.
>
> At first I was using a Transaction so that I could roll back the whole
> operation in the event of a failure. I changed it to use NoTx(), but it
> didn't help.
>
> I'm using an UPDATE Account CONTENTS { <json> } UPSERT WHERE Id = "xxxxx"
> as the mechanism for inserting/updating the main record. Since that
> statement only returns a count of the records modified (1), I then go back
> and immediately SELECT FROM Account WHERE Id = "xxxxx".
>
> I had the best luck when I put a graph.commit() between the UPDATE and the
> SELECT statements.
>
> Is there a better way to do this? I coded a "graph.addVertex()", but I
> would still need to pre-check for existence and then UPDATE, because I
> don't see a single-call mechanism from Java for doing that, other than the
> UPSERT.
>
> My first implementation was in a Javascript function which followed the
> same logic, but it was (still is occassionally) deadlocking too.
>
> Any/all thoughts are welcome.
>
> Thanks very much,
>
> Patrick
>
>
> On Tue, Mar 31, 2015 at 10:52 AM, Colin wrote:
>
>> Hi Patrick,
>>
>> Are you sharing the same graph db connection among your threads doing the
>> querying?
>>
>> What's your design look like for writing/reading the database?
>>
>> Thanks,
>>
>> -Colin
>>
>> Orient Technologies
>>
>> The Company behind OrientDB
>>
>> On Monday, March 30, 2015 at 3:02:39 PM UTC-5, Patrick Hoeffel wrote:
>>>
>>>
>>> <https://lh3.googleusercontent.com/-ebTSvLLuih4/VRmrhCh1nCI/AAAAAAAAQ3c/JYGQAngQ8dg/s1600/OrientDB%2BDeadlock.PNG>
>>> OrientDB 2.0.5 on Windows Server 2012, client connecting from Win 7 Pro
>>>
>>> I have a Java class that is inserting a vertex and then adding outbound
>>> edges. I'm doing queries to figure out what intermediate data needs to also
>>> be created in order for my edges to be built properly, but something is
>>> causing a deadlock, and I can only get it to clear by restarting OrientDB.
>>> Here is the stack trace from Eclipse when this happens:
>>>
>>> If anyone has seen this before, please let me know.
>>>
>>> Thanks,
>>>
>>> Patrick
>>>
>> --
>>
>> ---
>>
>
>
> --
> Patrick Hoeffel
>
>
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