Commit Graph

1 Commits

Author SHA1 Message Date
Azat Khuzhin
81aeff2d2a Add _shard_num virtual column for the Distributed engine
With JOIN from system.clusters one can figure out from which server data
came.

TODO:
- optimization to avoid communicating with unrelated shards (for queries
  like "AND _shard_num = n")
- fix aliases (see tests with serverError expected)

v0: AddingConstColumnBlockInputStream
v2: VirtualColumnUtils::rewriteEntityInAst
v3: fix remote(Distributed) by appending _shard_num only if has been requested
2019-11-06 15:26:12 +03:00