cassandra-user mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From Dan Checkoway <dchecko...@gmail.com>
Subject Understanding SELECT * paging/ordering
Date Fri, 18 Mar 2016 21:58:47 GMT
Say I have a table with 50M rows in a keyspace with RF=3 in a cluster of 15
nodes (single local data center).  When I do "SELECT * FROM table" and page
through those results (with a fetch size of say 1000), I'd like to
understand better how that paging works.

Specifically, what determines the order in which which rows are returned?
And what's happening under the hood...i.e. is the coordinator fetching
pages of 1000 from each node, passing some sort of paging state to each
node, and the coordinator merges the per-node sorted result sets?

I thought maybe the results would be sorted by partition key, but that
doesn't seem to be the case (I'm not 100% sure about this).

I'm also curious how consistency level comes into play.  i.e. if I use ONE
vs. QUORUM vs. ALL, how that impacts where the results come from and how
they're ordered, merged, and who knows what else I don't know...  :-)

Very curious how this works.  Thanks in advance!

Mime
View raw message