Re: [Neo4j] Relationships stored order
Hello, Storing order required because it's fundamental structure property. If I do type "get (title) (book)" that always should be "title from book" & never "book from title" because meaning are different (but second expression is also valid). As you can see both expressions are valid but have different evaluation results. Graph created for that expressions is this (simplified): node(get) -> link -> node(title) & node(get) -> link -> node(book) , note that node(get) is same node. Now, if query node(get) for children order should be counted: 1 relationship to node(title), 2 relationship to node(book) This is "down order" requirement, but there also "up order" one. The graph is compressing on fly, so that mean that "get (title) (book)" & "get (author) (book)" sharing node(book). Same time from node(book) it should be possible to go back to node(get). Remember that there are two node(get) and "up order" procedure must find correct one. For now we using lucene and preparing berkeley db index, but interesting to search for better performance too. On Fri, Nov 4, 2011 at 4:56 AM, David Montag wrote: > Do they need to be sorted because of some arbitrary reason, or because > you're storing data structures like lists that you want to preserve the > order of? > > David > > On Thu, Nov 3, 2011 at 4:44 PM, Evgeny Gazdovsky >wrote: > > > 2011/11/4 David Montag > > > > > Hi Evgeny, > > > > > > Could you maybe describe the use case behind this requirement a bit > more? > > > > > > > > We use the neo as persistent memory in the new age programming > > language. Every expression on this language is compiled into > > graph structure. So we need a graph with sorted relationships. > > And sort order is equal to the order in which relationships > > are created (stored). > > > -- Dmitriy Shabanov ___ Neo4j mailing list User@lists.neo4j.org https://lists.neo4j.org/mailman/listinfo/user
Re: [Neo4j] Relationships stored order
Do they need to be sorted because of some arbitrary reason, or because you're storing data structures like lists that you want to preserve the order of? David On Thu, Nov 3, 2011 at 4:44 PM, Evgeny Gazdovsky wrote: > 2011/11/4 David Montag > > > Hi Evgeny, > > > > Could you maybe describe the use case behind this requirement a bit more? > > > > > We use the neo as persistent memory in the new age programming > language. Every expression on this language is compiled into > graph structure. So we need a graph with sorted relationships. > And sort order is equal to the order in which relationships > are created (stored). > > -- > Evgeny > ___ > Neo4j mailing list > User@lists.neo4j.org > https://lists.neo4j.org/mailman/listinfo/user > -- David Montag Neo Technology, www.neotechnology.com Cell: 650.556.4411 Skype: ddmontag ___ Neo4j mailing list User@lists.neo4j.org https://lists.neo4j.org/mailman/listinfo/user
Re: [Neo4j] Relationships stored order
2011/11/4 David Montag > Hi Evgeny, > > Could you maybe describe the use case behind this requirement a bit more? > > We use the neo as persistent memory in the new age programming language. Every expression on this language is compiled into graph structure. So we need a graph with sorted relationships. And sort order is equal to the order in which relationships are created (stored). -- Evgeny ___ Neo4j mailing list User@lists.neo4j.org https://lists.neo4j.org/mailman/listinfo/user
Re: [Neo4j] Relationships stored order
Hi Evgeny, Could you maybe describe the use case behind this requirement a bit more? Thanks, David On Sun, Oct 30, 2011 at 4:01 PM, Evgeny Gazdovsky wrote: > PS > We don't need a traverse through relationships > in stored order, only iterations for start or end node. > > -- > Evgeny > ___ > Neo4j mailing list > User@lists.neo4j.org > https://lists.neo4j.org/mailman/listinfo/user > -- David Montag Neo Technology, www.neotechnology.com Cell: 650.556.4411 Skype: ddmontag ___ Neo4j mailing list User@lists.neo4j.org https://lists.neo4j.org/mailman/listinfo/user
Re: [Neo4j] Relationships stored order
2011/10/31 Dmitriy Shabanov > Hi, > > Berkeley Db index looks better for that. It was updated to serve our needs, > but better performance required. > > Mattias, do you know low storage structure? Maybe, it'll possible to use > some structural conditions to restore relationships order. At current > design we have two writes for one relationship, that always 2 times slow > than one =) > Neo4j doesn't have this type of ordering on the store level, and my best guess would be some kind of index. If the index is just used for ordering and there's a performance problem maybe you could stack up relationships and batch index them at a later time? > > On Mon, Oct 31, 2011 at 6:45 PM, Mattias Persson > wrote: > > > You can use what you wrote and then use lucene numeric range query to do > > the trick: > > > > Index index = ... > > index.add( rel2, "ORDER", ValueContext.numeric(2) ); > > index.add( rel3, "ORDER", ValueContext.numeric(3) ); > > index.add( rel1, "ORDER", ValueContext.numeric(1) ); > > > > // For all relationships > > index.query( new QueryContext( NumericRangeQuery.newIntRange( > > "ORDER",null,null,true,true ) ).sortNumeric( "ORDER", false ) ); > > // For a range > > index.query( new QueryContext( NumericRangeQuery.newIntRange( > > "ORDER",2,10,true,true ) ).sortNumeric( "ORDER", false ) ); > > > > -- > Dmitriy Shabanov > ___ > Neo4j mailing list > User@lists.neo4j.org > https://lists.neo4j.org/mailman/listinfo/user > -- Mattias Persson, [matt...@neotechnology.com] Hacker, Neo Technology www.neotechnology.com ___ Neo4j mailing list User@lists.neo4j.org https://lists.neo4j.org/mailman/listinfo/user
Re: [Neo4j] Relationships stored order
Hi, Berkeley Db index looks better for that. It was updated to serve our needs, but better performance required. Mattias, do you know low storage structure? Maybe, it'll possible to use some structural conditions to restore relationships order. At current design we have two writes for one relationship, that always 2 times slow than one =) On Mon, Oct 31, 2011 at 6:45 PM, Mattias Persson wrote: > You can use what you wrote and then use lucene numeric range query to do > the trick: > > Index index = ... > index.add( rel2, "ORDER", ValueContext.numeric(2) ); > index.add( rel3, "ORDER", ValueContext.numeric(3) ); > index.add( rel1, "ORDER", ValueContext.numeric(1) ); > > // For all relationships > index.query( new QueryContext( NumericRangeQuery.newIntRange( > "ORDER",null,null,true,true ) ).sortNumeric( "ORDER", false ) ); > // For a range > index.query( new QueryContext( NumericRangeQuery.newIntRange( > "ORDER",2,10,true,true ) ).sortNumeric( "ORDER", false ) ); > -- Dmitriy Shabanov ___ Neo4j mailing list User@lists.neo4j.org https://lists.neo4j.org/mailman/listinfo/user
Re: [Neo4j] Relationships stored order
You can use what you wrote and then use lucene numeric range query to do the trick: Index index = ... index.add( rel2, "ORDER", ValueContext.numeric(2) ); index.add( rel3, "ORDER", ValueContext.numeric(3) ); index.add( rel1, "ORDER", ValueContext.numeric(1) ); // For all relationships index.query( new QueryContext( NumericRangeQuery.newIntRange( "ORDER",null,null,true,true ) ).sortNumeric( "ORDER", false ) ); // For a range index.query( new QueryContext( NumericRangeQuery.newIntRange( "ORDER",2,10,true,true ) ).sortNumeric( "ORDER", false ) ); 2011/10/31 Evgeny Gazdovsky > PS > We don't need a traverse through relationships > in stored order, only iterations for start or end node. > > -- > Evgeny > ___ > Neo4j mailing list > User@lists.neo4j.org > https://lists.neo4j.org/mailman/listinfo/user > -- Mattias Persson, [matt...@neotechnology.com] Hacker, Neo Technology www.neotechnology.com ___ Neo4j mailing list User@lists.neo4j.org https://lists.neo4j.org/mailman/listinfo/user
Re: [Neo4j] Relationships stored order
PS We don't need a traverse through relationships in stored order, only iterations for start or end node. -- Evgeny ___ Neo4j mailing list User@lists.neo4j.org https://lists.neo4j.org/mailman/listinfo/user
Re: [Neo4j] Relationships stored order
2011/10/31 Mattias Persson > No, are you thinking about ordering them after property value or by type or > something else? > > Just we use a special relationships index for storing the order of relationships. Like: r = node.creareRelationship(parent, type); index.add(r, "ORDER", 1); r = node.creareRelationship(parent, type); index.add(r, "ORDER", 2); And the query via sort() to get relationships in right order. This way have a very bad performance. So, I have a question, is there a way get the relationships in stored sorted order in neo? If no, I suggest to create optional index (db) on the existing neo's low level storage for this. We can use an external storage (just we use bdb-index for the our key-value cache), but think this like on existing neo's data files, isn't it? -- Evgeny ___ Neo4j mailing list User@lists.neo4j.org https://lists.neo4j.org/mailman/listinfo/user
Re: [Neo4j] Relationships stored order
No, are you thinking about ordering them after property value or by type or something else? 2011/10/30 Evgeny Gazdovsky > Hello! > > Is there way to get relationships in the stored order in the neo? > > -- > Evgeny > ___ > Neo4j mailing list > User@lists.neo4j.org > https://lists.neo4j.org/mailman/listinfo/user > -- Mattias Persson, [matt...@neotechnology.com] Hacker, Neo Technology www.neotechnology.com ___ Neo4j mailing list User@lists.neo4j.org https://lists.neo4j.org/mailman/listinfo/user
[Neo4j] Relationships stored order
Hello! Is there way to get relationships in the stored order in the neo? -- Evgeny ___ Neo4j mailing list User@lists.neo4j.org https://lists.neo4j.org/mailman/listinfo/user
