citus/src/backend
Onur Tirtir c24088e12f Fix lower boundary calculation when pruning range dist table shards (#5082)
This happens only when we have a "<" or "<=" filter on distribution
column of a range distributed table and that filter falls in between
two shards.

When the filter falls in between two shards:

  If the filter is ">" or ">=", then UpperShardBoundary was
  returning "upperBoundIndex - 1", where upperBoundIndex is
  exclusive shard index used during binary seach.
  This is expected since upperBoundIndex is an exclusive
  index.

  If the filter is "<" or "<=", then LowerShardBoundary was
  returning "lowerBoundIndex + 1", where lowerBoundIndex is
  inclusive shard index used during binary seach.
  On the other hand, since lowerBoundIndex is an inclusive
  index, we should just return lowerBoundIndex instead of
  doing "+ 1". Before this commit, we were missing leftmost
  shard in such queries.

* Remove useless conditional branches

The branch that we delete from UpperShardBoundary was obviously useless.

The other one in LowerShardBoundary became useless after we remove "+ 1"
from there.

This indeed is another proof of what & how we are fixing with this pr.

* Improve comments and add more

* Add some tests for upper bound calculation too

(cherry picked from commit b118d4188e)
2021-07-07 13:13:50 +03:00
..
columnar Grant read access for columnar metadata tables to unprivileged user 2021-03-01 15:02:57 +03:00
distributed Fix lower boundary calculation when pruning range dist table shards (#5082) 2021-07-07 13:13:50 +03:00
.gitignore Initial commit of Citus 5.0 2016-02-11 04:05:32 +02:00