order by pk/fk desc limit x needs a reverse BT iterator

shunwang / redisql

Automatically exported from code.google.com/p/redisql

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order by pk/fk desc limit x needs a reverse BT iterator #12

Open GoogleCodeExporter opened 9 years ago

GoogleCodeExporter commented 9 years ago

currently doing an 
ORDER BY PK/FK DESC LIMIT X will read in ALL matching rows, sort backwards and 
then return X
Instead a reverse iterator should be employed on the BTREE and the first X 
displayed

Time Estimate: 2 days

Original issue reported on code.google.com by jaksprats on 14 Oct 2010 at 10:59

GoogleCodeExporter commented 9 years ago

There is another BTree enhancement that will take precedence over the 
DESC-iterator, which is rarely used.

The BTree enhancement will be to store the number-of-descendants in each node 
and use this on COUNT(*) requests of LIMIT OFFSET requests.

Original comment by jaksprats on 12 Jan 2011 at 10:33