This is two questions for one solution. I want to put a blog post
together on this if it's right.
I am playing with htable.batch for multi get to see if I can remove my
external hbase indexes. This is what I am trying to do.
#1 What is the best model for a column family that is just used as an
index?
Currently I am using a columns family _idx_ with:
column:<row>
value:<timstamp>
This allows me to have a new column for each index with a value of when
it was added. That allows me to purge the column family by the value
greater than some time in Map reduce.
#2 What is the most performant way to get this back into a get object?
This is what I am doing so far but want to validate my thoughts.
Configuration config = HBaseConfiguration.create();
HTableDescriptor transactionsbycompany_descriptor = new
HTableDescriptor(table);
HTable transactionsbycompany_table = new HTable(config,
transactionsbycompany_descriptor.getName());
HTable transactions_table = new HTable(config,
transactions_descriptor.getName());
List<Row> gets = new ArrayList<Row>();
Get g = new Get(Bytes.toBytes(key));
Result result = transactionsbycompany_table.get(g);
NavigableMap<byte[], byte[]> nmap = result.getFamilyMap(Bytes.toBytes(colfam_index));
Set<byte[]> keySet = nmap.keySet();
Iterator<byte[]> iter = keySet.iterator();
HTableDescriptor transactions_descriptor = new
HTableDescriptor("transactions");
while (iter.hasNext()) {
byte[] idx_key = iter.next();
Get get = new Get(idx_key);
get.addColumn(Bytes.toBytes("details"), Bytes.toBytes("amount"));
gets.add(get);
}
Result[] multiRes = new Result[gets.size()];
try {
transactions_table.batch(gets, multiRes);
} catch (InterruptedException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
With appreciation;
Wade Arnold
