Changes test files in multi and multi-1 schedules such that they
accomodate coordinator in metadata.
Changes fall into the following buckets:
1. When coordinator is in metadata, reference table shards are present
in coordinator too.
This changes test outputs checking the table size, shard numbers etc.
for reference tables.
2. When coordinator is in metadata, postgres tables are converted to
citus local tables whenever a foreign key relationship to them is
created. This changes some test cases which tests it should not be
possible to create foreign keys to postgres tables.
3. Remove lines that add/remove coordinator for testing purposes.
Given that we drop DEFAULT nextval('sequence') expressions from
shard relation columns, allowing `ON DELETE/UPDATE SET DEFAULT`
on such columns might cause inserting NULL values as a result
of a delete/update operation.
For this reason, we disallow ON DELETE/UPDATE SET DEFAULT actions
on columns that default to sequences.
DESCRIPTION: Disallows having ON DELETE/UPDATE SET DEFAULT actions on
columns that default to sequences
Fixes#6339.
Introduces a new GUC named citus.skip_constraint_validation, which basically skips constraint validation when set to on.
For some several places that we hack to skip the foreign key validation phase, now we use this GUC.
We have one replication of reference table for each node. Therefore all problems with
replication factor > 1 also applies to reference table. As a solution we will not allow
foreign keys on reference tables. It is not possible to define foreign key from, to or
between reference tables.
With this PR, we add foreign key support to ALTER TABLE commands. For now,
we only support foreign constraint creation via ALTER TABLE query, if it
is only subcommand in ALTER TABLE subcommand list.
We also only allow foreign key creation if replication factor is 1.
With this change, we now push down foreign key constraints created during CREATE TABLE
statements. We also start to send foreign constraints during shard move along with
other DDL statements