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DOAN DuyHai commented on CASSANDRA-10661:
-----------------------------------------
Hello [~xedin], it's me again.
I've had some discussion with search people and they told me that wildcard
searches (name like "\*xxxxx\*") are very expensive. Classical data structure
like suffix trees are adapted for suffix searching (name like "xxx\*"). For
prefix search (name like "\*xxx") they're creating a *reversed* index. Does it
mean that the CONTAINS mode (formerly named SUFFIX) is more expensive than the
NORMAL search mode ? If yes, how much expensive is it (x2 ? order of magnitude
?)
Second question, more related to the impl, since you query the nodes following
the token range and do not hit all nodes like normal secondary index, does it
imply that *sorting* (ORDER BY) is no longer relevant since you do not
retrieve all possible results ? (I've seen in QueryPlan.MAX_ROWS that there is
a hard-coded limit of 10 000 results)
Sorry to annoy you with my questions but they are important so that we,
evangelists, can give the right use-cases for users and especially deter them
from mis-using SASI when it's not appropriate or when the search cost is
prohibitive.
> Integrate SASI to Cassandra
> ---------------------------
>
> Key: CASSANDRA-10661
> URL: https://issues.apache.org/jira/browse/CASSANDRA-10661
> Project: Cassandra
> Issue Type: Improvement
> Components: Local Write-Read Paths
> Reporter: Pavel Yaskevich
> Assignee: Pavel Yaskevich
> Labels: sasi
> Fix For: 3.x
>
>
> We have recently released new secondary index engine
> (https://github.com/xedin/sasi) build using SecondaryIndex API, there are
> still couple of things to work out regarding 3.x since it's currently
> targeted on 2.0 released. I want to make this an umbrella issue to all of the
> things related to integration of SASI, which are also tracked in
> [sasi_issues|https://github.com/xedin/sasi/issues], into mainline Cassandra
> 3.x release.
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