This fix ensures that the expected DEBUG error messages from the router
planner in `multi_router_planner`, `multi_router_planner_fast_path` and
`query_single_shard_table` are present with PG17.
In `query_single_shard_table` the diff:
```
SELECT COUNT(*) FROM citus_local_table t1
WHERE t1.b IN (
SELECT b+1 FROM nullkey_c1_t1 t2 WHERE t2.b = t1.a
);
-DEBUG: router planner does not support queries that reference non-colocated distributed tables
+DEBUG: Local tables cannot be used in distributed queries.
```
occurred because of[ this PG17
commit](https://git.postgresql.org/gitweb/?p=postgresql.git;a=commitdiff;h=9f1337639)
which enables the optimizer to pull up a correlated ANY subquery to a
join. The fix inhibits subquery pull up by including a volatile function
in the predicate involving the ANY subquery, preserving the pre-PG17
optimizer treatment of the query.
In the case of `multi_router_planner` and
`multi_router_planner_fast_path` the diffs:
```
-- partition_column is null clause does not prune out any shards,
-- all shards remain after shard pruning, not router plannable
SELECT *
FROM articles_hash a
WHERE a.author_id is null;
-DEBUG: Router planner cannot handle multi-shard select queries
+DEBUG: Creating router plan
```
are because of [this PG17
commit](https://git.postgresql.org/gitweb/?p=postgresql.git;a=commitdiff;h=b262ad440),
which enables the optimizer to detect and remove redundant IS (NOT) NULL
expressions. The fix is to adjust the table definition so the column
used for distribution is not marked NOT NULL, thus preserving the
pre-PG17 query planning behavior.
Finallly, a rule is added to `normalize.sed` to ignore DEBUG logging in CREATE MATERIALIZED
VIEW AS statements introduced by [this PG17
commit](https://git.postgresql.org/gitweb/?p=postgresql.git;a=commitdiff;h=b4da732fd64);
_when creating materialized views, use REFRESH logic to load data_, a
consequence of which is that with `client_min_messages` at `DEBUG2`
Postgres emits extra detail for CREATE MATERIALIZED VIEW AS statements.
```
CREATE MATERIALIZED VIEW mv_articles_hash_empty AS
SELECT * FROM articles_hash WHERE author_id = 1;
DEBUG: Creating router plan
DEBUG: query has a single distribution column value: 1
+DEBUG: drop auto-cascades to type multi_router_planner.pg_temp_61391
+DEBUG: drop auto-cascades to type multi_router_planner.pg_temp_61391[]
```
The rule can be changed to a normalization, or possibly dropped, when 17 becomes the minimum supported version.
Tradionally our planner works in the following order:
router - > pushdown -> repartition -> pull to coordinator
However, for INSERT .. SELECT commands, we did not support "router".
In practice, that is not a big issue, because pushdown planning can
handle router case as well.
However, with PG 16, certain outer joins are converted to JOIN without
any conditions (e.g., JOIN .. ON (true)) and the filters are pushed down
to the tables.
When the filters are pushed down to the tables, router planner can
detect. However, pushdown planner relies on JOIN conditions.
An example query:
```
INSERT INTO agg_events (user_id)
SELECT raw_events_first.user_id
FROM raw_events_first LEFT JOIN raw_events_second
ON raw_events_first.user_id = raw_events_second.user_id
WHERE raw_events_first.user_id = 10;
```
As a side effect of this change, now we can also relax certain
limitation that "pushdown" planner emposes, but not "router". So, with
this PR, we also allow those.
Closes https://github.com/citusdata/citus/pull/6772
DESCRIPTION: Prevents unnecessarily pulling the data into coordinator
for some INSERT .. SELECT queries that target a single-shard group
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.
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