I'm still in the evaluation of *Neo4j *vs. *OrientDB*. Most importantly I
need Lucene as full-text index engine. So I created on both databases the
same schema with the same data (300Mio lines). I'm also experienced with
querying different things in both systems. I used the Standard Analyzer on
both sides. The OrientDB test query results are all fine and really good in
terms of reliability and speed. The speed of Neo4j is also ok but the
results are kind of bad in most of the cases. So let's come to the
different issues I have with Neo4j Lucene indexing. I always give you an
example of how it would look in OrientDB and which result set you should be
getting out of the query.
So in these examples, there are Applns that have title(s). Titles are
indexed with Lucene in both databases. Applns also have an ID just to
demonstrate the ordering. At the end of each query I have some *questions*
about them. It would be great to get some *feedback *or even *answers *about
them.
Query #0: One word query with no order
Well this query is very simple. It shall be tested how the database behave
if there is just a simple word and nothing else. As you can see the Neo4j
result is way longer then the one from OrientDB. OrientDB is using TFIDF to
keep the results short and more reliable to the actual search. As you can
see as first result in OrientDB, there is title with SOLAR. That is totally
missing in Neo4j, too.
In Neo4j: *START n=node:titles('title:solar') RETURN n.title,n.ID LIMIT 10*
1. SOLAR RADIATION SHIELDING PARTICULATE AND SOLAR RADIATION SHIELDING
RESIN MATERIAL DISPERSED WITH ... 38321319
2. Solar module for cooling solar cells on the underside of a solar
panel has air inlet and outlet openings ... 12944121
3. Solar construction component for solar thermal assemblies, solar
thermal assembly, method for operating a solar... 324146113
4. ...
In OrientDB: *SELECT title,ID FROM Appln WHERE title LUCENE "solar" LIMIT
10*
1. SOLAR 24900187
2. Solar unit and solar apparatus 1876343
3. Solar module with solar concentrator 13496706
4. ...
Questions:
1. Why is Neo4j not using TFIDF or what do they use instead?
2. Is Neo4j able to use some ordering of the keyword match?
3. Is it possible to change TFIDF to somethign else in OrientDB?
Query #1: One word query with order by ID
Neo4j is ordering the ID's before using TFIDF. As known from Query#0 Neo4j
is not using TFIDF so it's basically just searching via first results of
the Lucene query. In OrientDB besides it's still searching by good TFIDF's
and then ordering.
In Neo4j:* START n=node:titles('title:solar') RETURN n.title,n.ID ORDER BY
n.ID ASC LIMIT 10*
1. Stackable flat-roof/floor frame for solar panels 318
2. Method for producing contact for solar cells 636
3. Solar cell and fabrication method thereof 1217
4. ...
In OrientDB: *SELECT title,ID FROM Appln WHERE title LUCENE "solar" ORDER
BY ID ASC LIMIT 10*
1. Solar unit and solar apparatus 1876343
2. Solar module with solar concentrator 13496706
3. SOLAR TRACKER FOR SOLAR COLLECTOR 16543688
4. ...
Questions:
1. How would a search in OrientDB look like that should be ordered by
the ID and still matching the best TFIDF of them.
2. Is there a way in Neo4j to order the Lucene match before ordering by
the ID?
Query #2: One word with using a star search
Star search had no influence on the Neo4j results. OrientDB results changed
in a good way.
In Neo4j: *START n=node:titles('title:solar*') RETURN n.title,n.ID ORDER BY
n.ID ASC LIMIT 10*
1. Stackable flat-roof/floor frame for solar panels 318
2. Method for producing contact for solar cells 636
3. Solar cell and fabrication method thereof 1217
4. ...
In OrientDB: *SELECT title,ID FROM Appln WHERE title LUCENE "solar*" ORDER
BY ID ASC LIMIT 10*
1. High performance solar methane generator 8354701
2. All-plastic honeycomb solar water-heater 8355379
3. Plate type solar energy heat collector plate core and its
manufacturing method 8356173
4. ...
Questions:
1. Does Neo4j ignore star searches?
Query #3: Searching for 2 words devided by a space
The strange here is that you need to change 'title:solar panel' to that
query here. Otherwhise you just get errors. OrientDB seems good so far.
In Neo4j:* START n=node:titles(title="solar panel") RETURN n.title,n.ID
ORDER BY n.ID ASC LIMIT 10*
1. Returned 0 rows in 817 ms
In OrientDB: *SELECT title,ID FROM Appln WHERE title LUCENE "solar panel"
ORDER BY ID ASC LIMIT 10*
1. SOLAR PANEL 1584567
2. SOLAR PANEL 1616547
3. SOLAR PANEL 2078382
4. SOLAR PANEL 2078383
5. Solar panel 2178466
6. ...
Questions:
1. Why does Neo4j need a special Query here to at least don't throw any
error?
2. Why is the query failing and not giving anything back? I know that
Neo4j is searching here for lower letters, so it's case sensitive. But why
it is like this? I mean I use the default analyzer and the doc of Neo4j
Lucene says it's true, so it means to_lower_letter.
Query #4: Now searching for the same query in capital letters
The same issue like in #3. In Neo4j just searching returning the capital
letters results of the words. OrientDB results looking fine again.
In Neo4j: *START n=node:titles(title="SOLAR PANEL") RETURN n.title,n.ID
ORDER BY n.ID ASC LIMIT 10*
1. SOLAR PANEL 348800
2. SOLAR PANEL 420683
3. SOLAR PANEL 1393804
4. SOLAR PANEL 1584567
5. SOLAR PANEL 1616547
6. ...
In OrientDB: *SELECT title,ID FROM Appln WHERE title LUCENE "SOLAR PANEL"
ORDER BY ID ASC LIMIT 10*
1. SOLAR PANEL 1584567
2. SOLAR PANEL 1616547
3. SOLAR PANEL 2078382
4. SOLAR PANEL 2078383
5. Solar panel 2178466
6. ...
Questions:
1. Same question like in #3, how to search with to_lower_letter?
Query #5: Combining two words and using the star search
Here I want to combine words search with star search. But with the equal
search I'm not able to find matches because he expects the star as usual
sign in the title. But I'm not able to say 'title:SOLAR PANEL*'. That's
also forbidden. In OrientDB everything is fine.
In Neo4j: *START n=node:titles(title="SOLAR PANEL*") RETURN n.title,n.ID
ORDER BY n.ID ASC LIMIT 10*
1. Returned 0 rows in 895 ms
In OrientDB:* SELECT title,ID FROM Appln WHERE title LUCENE "SOLAR PANEL*"
ORDER BY ID ASC LIMIT 10*
1. SOLAR PANELS 1405717
2. SOLAR PANEL 1584567
3. SOLAR PANEL 1616547
4. SOLAR PANEL 2705081
5. Solar Panel 2766555
6. ...
Questions:
1. How can you combine some words with the star search in Neo4j?
Query #6: Counting query results
The last thing I really need is a fast lookup how many results are there
overall. Here Neo4j is finding a result way faster but always finding less
matches then OrientDB. Searching for Solar is kind of close to each other.
But another test was not that close.
In Neo4j: *START n=node:titles("title:Solar") RETURN count(*)*
143211 in 220 sec
In OrientDB: *SELECT count(*) title FROM Appln WHERE title LUCENE "Solar"
LIMIT -1*
148029 in 50 sec
Questions:
1. How can that lookup times be improved on both systems?
2. Why does both systems find different number of matches? Also happens
on other keywords. Maybe other indexing eninge used?
Well that is everything for now. If you need any other query just tell me
and I deliver it.
I think it's very important to compare the Lucene implementation because
with Millions of nodes Lucene has to many advantages. Thanks for any small
tip.
Btw: please don't give tips about using Java code instead for the query. I
want to use Cypher because the request shall be done in the browser, like
in OrientDB. I know that everything here is easily be done with Java code.
Thank you.
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