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Pavel Trukhanov commented on CASSANDRA-6167: -------------------------------------------- {code}LIMIT UNTIL condition {code}? > Add end-slice termination predicate > ----------------------------------- > > Key: CASSANDRA-6167 > URL: https://issues.apache.org/jira/browse/CASSANDRA-6167 > Project: Cassandra > Issue Type: Improvement > Components: CQL > Reporter: Tupshin Harper > Priority: Minor > Labels: cql > > When doing performing storage-engine slices, it would sometimes be beneficial > to have the slice terminate for other reasons other than number of columns or > min/max cell name. > Since we are able to look at the contents of each cell as we read it, this is > potentially doable with very little overhead. > Probably more challenging than the storage-engine implementation itself, is > to come up with appropriate CQL syntax (Thrift, should we decide to support > it, would be trivial). > Two possibilities ar > 1) special where function: > SELECT pk,event from cf WHERE pk IN (1,5,10,11) AND > partition_predicate({predicate}) > or a bigger language change, but i think one I prefer. more like: > 2) SELECT pk,event from cf where pk IN (1,5,10,11) UNTIL PARTITION event > {predicate} > Neither feels perfect, but I do like the fact that the second one at least > clearly states what it is intended to do. > By using "UNTIL PARTITION", we could re-use the UNTIL keyword to handle other > kinds of early-termination of selects that the coordinator might be able to > do, such as stop retrieving additional rows from shards after a particular > criterion was met. -- This message was sent by Atlassian JIRA (v6.3.4#6332)