- add support for queries that use
union all operator with global tables
- for the case when global table is
used against sharded table, the global
table is materialized only on single
storage, on all other storages the
global child of union all is not
materialized

- Support groupby, aggregates and having
when the child has Global distribution:
in this case we simply don't do 2-stage
aggregation and execute everything in stage
on one node.

- subqueries reading from global tables are supported
- subqueries in queries which scan the global tables
are allowed:
`select a from global where b in (select c from segment)`

However currently using global tables in join is not
supported.

All materialized table on the storages are now fully temporary and
do not leave any records in WAL. Statistics table are left data
temporary as there is no need to recreate them on every restart.

BREAKING CHANGE!: renamed __SBROAD_STAT into _sql_stat,
__SBROAD_QIERY into _sql_query.

1. _sql_stat primary key also includes the parent_span cause
   we support PG extended protocol and we need to bind same spans
   to different trees.
2. Fix some bugs in the telemetry for queries.

Arseniy Volynets authored 1 year ago and Denis Smirnov committed 1 year ago

- now Motion(Full) has Global distribution
- Relational::Values has Any distribution
- Replicated distribution was removed, Distribution::Any is
used instead for projection with constants

feat: add checks on table columns creation and insertion, add check on parameters number, add support of is_nullable metadata

When reading from multiple storages it is
possible that some requests will execute faster
than the others. And it could lead to wrong
results when vhard moved the buckets between
nodes.

For example: we execute `select * from t`
on storage 1 and get the results. Vshard
moves the data from storage 1 to stroage 2,
and then we execute `select * from t` and in
result we get the data (that moved) twice.

This commit fixes it by using vshard's
storage ref api. Now multi-node read requests
first create the ref on each node which
blocks vshard rebalancing. Then we call
our stored procedure and remove the ref.