Alexander Tolstoy authored 1 year ago and Denis Smirnov committed 1 year ago

Also fix UnionAll and Except references.

BREAKING CHANGE!: local motion now means local materialization
of results on the storage without bucket calculation. The old
logic of "do nothing" was moved into none motion.

Implement delete SQL operator. It is always executed locally as we
delete already existing tuples and never change tuple buckets.
We reinvent the logic of the local motion policy (see the desclamer
in this commit) and materialize the primary keys from projection on
the storage. Then they are removed from the space via space API in
a single local transaction.

We need this information to perform delete and update operations
using space API in future.

Option sql_vdbe_max_steps stops long running
queries from blocking tx thread or queries that 
use too much memory during local execution. 

Each sql query is compiled into VDBE opcodes on storages. This
parameter sets max number of opcodes that VDBE
can execute.

Example: `select * from t option(sql_vdbe_max_steps=1000)`

Option vtable_max_rows limits the maximum number of rows in
virtual table. This limit is checked on storages before returning
intermediate results and on routers when receiving results from
storages.

Example: `select * from t option(vtable_max_rows=1000)`

* added HAVING clause. HAVING condition may contain aggregates. Any column outside aggregate function must be part of a grouping expression. 

E.g: `select sum(a) from t group by b having c > 1` Above query is invalid, because `c` is not a grouping expression.