This is consistently slow. I made a graph which just goes off of the
root reference node (0) and I am seeing the following...
(0)$ cd 1 <about 1 minute>
(1)$ cd 0 <instant>
(0)$ cd 1 <about 1 minute>
It's almost like it is scanning the entire relationship list before
actually looking up the next node. Of note I have found the following
when running neoclipse...
WARNING: [</path/to/neo4j-db>/neostore.relationshipstore.db] Unable
to memory map
And I see this in the logs...
neostore.nodestore.db.mapped_memory=20M
neostore.propertystore.db.arrays.mapped_memory=130M
neostore.propertystore.db.index.keys.mapped_memory=1M
neostore.propertystore.db.index.mapped_memory=1M
neostore.propertystore.db.mapped_memory=90M
neostore.propertystore.db.strings.mapped_memory=130M
neostore.relationshipstore.db.mapped_memory=100M
Am I missing something obvious? Even without memory maps, I would expect
this to be somewhat faster since reading 156MB (the size of my
neostore.relationshipstore.db file) of relation data should be very
fast. Also, is there anyway to do a pre-warm up so that the first hit
isn't so slow? I would hate for my first user in PROD to get hammered
because a cache wasn't warmed up.
Thanks,
Andrew
On 07/06/2011 09:24 AM, Rick Bullotta wrote:
> Hi, Andrew.
>
> In general, this scenario (1 million+ relationships on a node) can be slow,
> but usually only the first time you access the node. If you're only
> accessing the node once in a session, then yes, it will seem sluggish. The
> Neoclipse issue is probably a combination of two issues: the first is lazily
> loading the node information the first time, and the second is the visual
> rendering of all those relationships.
>
> Rick
>
> -----Original Message-----
> From: user-boun...@lists.neo4j.org [mailto:user-boun...@lists.neo4j.org] On
> Behalf Of Andrew White
> Sent: Wednesday, July 06, 2011 10:15 AM
> To: user@lists.neo4j.org
> Subject: [Neo4j] Performance issue on nodes with lots of relationships
>
> I have a graph with roughly 10M nodes. Some of these nodes are highly
> connected to other nodes. For example I may have a single node with 1M+
> relationships. A good analogy is a population that has a "lives-in"
> relationship to a state. Now the problem...
>
> Both neoclipse or neo4j-shell are terribly slow when working with these
> nodes. In the shell I would expect a `cd<node-id>` to be very fast,
> much like selecting via a rowid in a standard DB. Instead, I usually see
> several seconds delay. Doing a `ls` takes so long that I usually have to
> just kill the process. In fact `ls` never outputs anything which is odd
> since I would expect it to "stream" the output as it found it. I have
> very similar performance issues with neoclipse.
>
> I am using Neo4j 1.3 embedded on Ubuntu 10.04 with 4GB of RAM.
> Disclaimer, I am new to Neo4j.
>
> Thanks,
> Andrew
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