return back virtual columns to distributed tables

This commit is contained in:
Anton Popov 2024-08-21 15:19:29 +00:00
parent 0bfc280f0d
commit e87de3cfcd
3 changed files with 36 additions and 0 deletions

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@ -290,6 +290,10 @@ VirtualColumnsDescription StorageDistributed::createVirtuals()
desc.addEphemeral("_shard_num", std::make_shared<DataTypeUInt32>(), "Deprecated. Use function shardNum instead");
/// Add virtual columns from table of storage Merges.
desc.addEphemeral("_database", std::make_shared<DataTypeLowCardinality>(std::make_shared<DataTypeString>()), "The name of database which the row comes from");
desc.addEphemeral("_table", std::make_shared<DataTypeLowCardinality>(std::make_shared<DataTypeString>()), "The name of table which the row comes from");
return desc;
}

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@ -0,0 +1,8 @@
1 t_local_1
2 t_local_2
1 t_local_1
2 t_local_2
1 1
2 1
1 1
2 1

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@ -0,0 +1,24 @@
DROP TABLE IF EXISTS t_local_1;
DROP TABLE IF EXISTS t_local_2;
DROP TABLE IF EXISTS t_merge;
DROP TABLE IF EXISTS t_distr;
CREATE TABLE t_local_1 (a UInt32) ENGINE = MergeTree ORDER BY a;
CREATE TABLE t_local_2 (a UInt32) ENGINE = MergeTree ORDER BY a;
INSERT INTO t_local_1 VALUES (1);
INSERT INTO t_local_2 VALUES (2);
CREATE TABLE t_merge AS t_local_1 ENGINE = Merge(currentDatabase(), '^(t_local_1|t_local_2)$');
CREATE TABLE t_distr AS t_local_1 engine=Distributed('test_shard_localhost', currentDatabase(), t_merge, rand());
SELECT a, _table FROM t_merge ORDER BY a;
SELECT a, _table FROM t_distr ORDER BY a;
SELECT a, _database = currentDatabase() FROM t_merge ORDER BY a;
SELECT a, _database = currentDatabase() FROM t_distr ORDER BY a;
DROP TABLE IF EXISTS t_local_1;
DROP TABLE IF EXISTS t_local_2;
DROP TABLE IF EXISTS t_merge;
DROP TABLE IF EXISTS t_distr;