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> shahbaz chaudhary wrote: >> >>Regarding aggregators, it looks like they are implemented by operating >>on two values at a time (looking at SumAggregator): a value to be >>added and a value which was populated previously (presumably >>containing aggregate result of column already traversed). So to be a little clearer, the aggregator operates on a single incoming value and a context object specific to the aggregator function. This context object is where you would maintain your list of previous values if required. Eg. for the max aggregator the context object would simply contain the current maximum value, for a top-three average it would maintain the top three values and calculate the final value at finish time. Dan. -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.2.5 (MingW32) Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org iD8DBQFCAnAEIv0S4qsbfuQRAq+6AKC4hHKjzNb7kRkCif3jMWSF48gRawCfX80b 0wti7Le5a0dylpqaWjqgn0c= =4U4m -----END PGP SIGNATURE-----
