Summary of DBXML 2.3.10 indexes

Question

We are running performance tests on our DBXML 2.3.10 database. There is still some question as to indexing numbers. Could someone briefly summarize the options? I don't think this is well documented (I could be wrong). For example:
1. Integers - There is no index type for integer, so what should we use?
2. Decimal -How does it differ from a float or double
3. Float/double - I assume this is the same idea as in the C language; single and double precision? Why would I not always use double if I am not concerned about memory? Does one perform better than the other.
Anthony

Answer 1

John,
Thanks for the summary. However, I must tell you that in terms of BDBXML, the decimal index does not function correctly based on our tests. I believe 2.3.8 cited problems, and I wrongly assumed 2.3.10 fixed it. Here are the details using DBXML Shell. I am using a container with 1125750 documents. A sample document is included at the end of the post
dbxml> listindexes
Index: node-element-equality-double for node {}:rabbits
This lookupindex works fine with the double index:
dbxml> time lookupindex node-element-equality-double {} rabbits
1125750 objects returned for eager index lookup 'node-element-equality-double'
Time in seconds for command 'lookupindex': 25.066
We can also use query to get the same data:
dbxml> time query 'for $a in collection("SCHEMA_1804635228.dbxml") where $a/sys:Metadata/sys:Published/theRabbit/theData[rabbits=1500] return $a'
1500 objects returned for eager expression 'for $a in collection("SCHEMA_1804635
228.dbxml") where $a/sys:Metadata/sys:Published/theRabbit/theData[rabbits=1500]
return $a'
Time in seconds for command 'query': 5.157
Now I delete the index:
dbxml> delindex {} rabbits node-element-equality-double
Deleting index type: node-element-equality-double from node: {}:rabbits
...And add the index, only this time it is decimal:
dbxml> addindex {} rabbits node-element-equality-decimal
Adding index type: node-element-equality-decimal to node: {}:rabbits
I verify the index:
dbxml> listindexes
Index: node-element-equality-decimal for node {}:rabbits
A Lookupindex yields about the same performance as when it was a double:
dbxml> time lookupindex node-element-equality-decimal {} rabbits
1125750 objects returned for eager index lookup 'node-element-equality-decimal'
Time in seconds for command 'lookupindex': 27.551
Now if I try to run a query to get the same data, asI did when it was a double index the performance is extremely poor:
dbxml> time query 'for $a in collection("SCHEMA_1804635228.dbxml") where $a/sys:
Metadata/sys:Published/theRabbit/theData[rabbits=1500] return $a'
1500 objects returned for eager expression 'for $a in collection("SCHEMA_1804635
228.dbxml") where $a/sys:Metadata/sys:Published/theRabbit/theDat[rabbits=1500]
return $a'
Time in seconds for command 'query': 629.097
I also tried to cast with similar results:
dbxml> time query 'for $a in collection("SCHEMA_1804635228.dbxml") where $a/sys:
Metadata/sys:Published/theRabbit/theData[rabbits=xs:decimal(1500)] return $a'
1500 objects returned for eager expression 'for $a in collection("SCHEMA_1804635
228.dbxml") where $a/sys:Metadata/sys:Published/theRabbit/theData[rabbits=xs:decimal(1500)] return $a'
Time in seconds for command 'query': 651.19
Sample document:
sys:Metadata xmlns:sys="http://jbischemas.rl.af.mil/schemas/sys">
<sys:Extended>
<im:BaseObject xmlns:im="http://jbischemas.rl.af.mil/schemas/im">
<im:InfoObjectType>
<im:Name>mil.af.rl.oim.benchmark.rabbit</im:Name>
<im:MajorVersion>1</im:MajorVersion>
<im:MinorVersion>0</im:MinorVersion>
</im:InfoObjectType>
<im:PublicationTime>2007-06-23T01:57:10Z</im:PublicationTime>
<im:InfoObjectID>4b6s1ot-fbp6si-f3907lwp-1-f39fyzol-o4n7</im:InfoObjectID>
<im:PublisherID>4b6s1ot-fbp6si-f3907lwp-1-f390cm3c-d</im:PublisherID>
<im:PlatformID>4b6s1ot-fbp6si-f3907lwp-1-f3908pog-4</im:PlatformID>
</im:BaseObject>
</sys:Extended>
<sys:Published>
<theRabbit>
<theData>
<rabbitUID>4b6s1ot-cpx4r3-f390ckhi-1-f390ckhx-2</rabbitUID>
<sequence_order_number>1500</sequence_order_number>
<total>1500</total>
<time_stamp_in_milliseconds>1182563830805</time_stamp_in_milliseconds>
<rabbits>1500</rabbits>
</theData>
</theRabbit>
</sys:Published>
</sys:Metadata>