Hi there,
On your second point, I don't think column family can ever be an optional
parameter, so I'm not sure this understanding is correct.
Regards,
Stas.
On 12 August 2013 17:22, Bing Li <lbl...@gmail.com> wrote:
> Hi, all,
>
> My understandings about HBase table and its family are as follows.
>
> 1) Each table can consist of multiple families;
>
> 2) When retrieving with SingleColumnValueFilter, if the family is
> specified, other families contained in the same table are not
> affected.
>
> Are these claims right? But I got a problem which conflicts with the
> above understandings.
>
> In the following code, even though no any data in the family of
> ContrivedNeighborStructure.NODE_NEIGHBOR_IN_GROUP_BASICS_FAMILY, the
> for-loop runs many times if other families has the column of
> ContrivedNeighborStructure.NODE_NEIGHBOR_IN_GROUP_DC_KEY_COLUMN.
>
> Is that normal in HBase? If so, I think it is not a good design. No
> column overlaps must exist among the families of the same table?
> Otherwise, retrieving the table must cause waste of scanning loops?
>
> Thanks so much!
>
> Best wishes,
> Bing
>
> SingleColumnValueFilter dcKeyFilter = new
>
> SingleColumnValueFilter(ContrivedNeighborStructure.NODE_NEIGHBOR_IN_GROUP_BASICS_FAMILY,
> ContrivedNeighborStructure.NODE_NEIGHBOR_IN_GROUP_DC_KEY_COLUMN,
> CompareFilter.CompareOp.EQUAL, new SubstringComparator(dcKey));
> Scan scan = new Scan();
> scan.setFilter(dcKeyFilter);
> scan.setCaching(Parameters.CACHING_SIZE);
> scan.setBatch(Parameters.BATCHING_SIZE);
>
> String qualifier;
> String hostNodeKey = SocialRole.NO_NODE_KEY;
> String groupKey = SocialGroup.NO_GROUP_KEY;
> int timingScale = TimingScale.NO_TIMING_SCALE;
> String key;
> try
> {
> ResultScanner scanner = this.neighborTable.getScanner(scan);
> for (Result result : scanner)
> {
> for (KeyValue kv : result.raw())
> {
> qualifier = Bytes.toString(kv.getQualifier());
> if
>
> (qualifier.equals(ContrivedNeighborStructure.NODE_NEIGHBOR_IN_GROUP_HOST_NODE_KEY_STRING_COLUMN))
> {
> hostNodeKey = Bytes.toString(kv.getValue());
> }
> else if
>
> (qualifier.equals(ContrivedNeighborStructure.NODE_NEIGHBOR_IN_GROUP_HOST_GROUP_KEY_STRING_COLUMN))
> {
> groupKey = Bytes.toString(kv.getValue());
> }
> else if
>
> (qualifier.equals(ContrivedNeighborStructure.NODE_NEIGHBOR_IN_GROUP_TIMING_SCALE_STRING_COLUMN))
> {
> timingScale = Bytes.toInt(kv.getValue());
> }
> }
> if (!hostNodeKey.equals(SocialRole.NO_NODE_KEY) &&
> !groupKey.equals(SocialGroup.NO_GROUP_KEY) && timingScale !=
> TimingScale.NO_TIMING_SCALE)
> {
> key = Tools.GetKeyOfNode(hostNodeKey, groupKey,
> timingScale);
> if (!neighborMap.containsKey(key))
> {
> neighborMap.put(key, new
> NodeNeighborInGroup(hostNodeKey, groupKey, timingScale));
> }
> }
> hostNodeKey = SocialRole.NO_NODE_KEY;
> groupKey = SocialGroup.NO_GROUP_KEY;
> timingScale = TimingScale.NO_TIMING_SCALE;
> }
> }
> catch (IOException e)
> {
> e.printStackTrace();
> }
>
