Thanks for the tips.
Yeah that is the model we had before, the problem is we can potentially have
millions of IDs for a given TYPE|VAL.
we are considering something like:
Row Key: TYPE|VALUE|ID
column: link:TYPE|VALUE
This is only because ID may never have more than a few TYPE|VAL results in
this current dataset, which would also eliminate the need to go to second
table.
Thanks for the help.
Jonathan Gray-2 wrote:
>
> Well you're trying to do a join. How much data is actually in TableB?
> You might consider denormalizing so that you don't have to query TableB,
> the data you need is already in TableA.
>
> You could use a Get (single trip) for the inner loop rather than a
> Scanner (which requires multiple round-trips). You could even use a Get
> for the outer loop by making your table wide instead of tall.
>
> Row Key: TYPE|VALUE
> Column: link:ID
>
> And you have a column for each ID within that TYPE|VALUE row.
>
> Also, don't forget to close your scanners if you do use scanners.
>
> JG
>
>
> llpind wrote:
>> Assume a schema like so:
>>
>> TableA======================
>> Row Key: TYPE|VALUE|ID
>> Column: link:ID (irrelevant)
>> TableB======================
>> Row Key: ID
>> Column: typeval:TYPE|VALUE
>> ===========================
>>
>>
>>
>> I need to iterate over the TableA using a Scanner to get all IDs based on
>> TYPE|VALUE, then for each ID I need to get from TableB what TYPE|VALUE’s
>> it’s tied to (a many to many).
>> Assume I have a list of TYPE|VALUES in a List, and need to process
>> through
>> this data. Done something like this:
>>
>>
>>
>> for (String typeVal : list){
>>
>> Scan tblAScan = new Scan(Bytes.toBytes(typeVal + “|”),
>> Bytes.toBytes(typeVal + “|A”)); //give me all IDs for matching TYPE|VAL
>> ResultScanner s1 = tblA.getScanner(tblAScan);
>>
>> for (Result tblBRowResult = s1.next(); tblBRowResult != null;
>> tblBRowResult = s1.next()){
>>
>> Scan tblBScan = new Scan(Bytes.toBytes(tblBRowResult.getValue() ),
>> Bytes.toBytes(typeVal + “ ”)); //IDs are all numeric
>> ResultScanner s2 = tblA.getScanner(tblAScan);
>> List results = s2.next().list(); //only care about column data here,
>> since ID is row key
>>
>> for (KeyValue kv : results){
>> //do stuff
>> kv.getValue();
>> }
>>
>> }
>>
>> }
>>
>
>
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