With this commit, we make sure that local execution adds the
intermediate result size as the distributed execution adds. Plus,
it enforces the citus.max_intermediate_result_size value.
We should not access CurrentLocalExecutionStatus directly because that
would mean that we could also set it directly, which we shouldn't
because we have checks to see if the new state is possible, otherwise we
error.
Before this commit, the logic was:
- As long as the outer side of the JOIN is not a JOIN (e.g., relation
or subquery etc.), we check for the existence of any recurring
tuples. There were two implications of this decision.
First, even if a subquery which is on the outer side contains
distributed table JOIN reference table, Citus would unnecessarily throw
an error. Note that, the JOIN inside the subquery would already
be going to be tested recursively. But, as long as that check
passes, there is no reason for the upper JOIN to fail. An example, which
used to fail and now works:
SELECT * FROM (SELECT * FROM dist JOIN ref) as foo LEFT JOIN dist;
Second, certain JOINs, especially with ON (true) conditions were not
represented as Citus expects the JOINs to be in the format
DeferredErrorIfUnsupportedRecurringTuplesJoin().
Use short lived per-tuple context in citus_evaluate_expr like
(pg) evaluate_expr does.
We should not use planState->ExprContext when evaluating expressions
as it might lead to freeing the same executor twice (first one happens
in citus_evaluate_expr itself and the other one happens when postgres
doing clean-up for the top level executor state), which in turn might
cause seg.faults.
However, now as we don't have necessary planState info to evaluate
prepared statements, we also add planState->es_param_list_info to
per-tuple ExprContext.
With postgres 13, there is a global lock that prevents multiple VACUUMs
happening in the current database. This global lock is taken for a short
time but this creates a problem because of the following:
- We execute the VACUUM for the shell table through the standard process
utility. In this step the global lock is taken for the current database.
- If the current node has shard placements then it tries to execute
VACUUM over a connection to localhost with ExecuteUtilityTaskList.
- the VACUUM on shard placements cannot proceed because it is waiting
for the global lock for the current database to be released.
- The acquired lock from the VACUUM for shell table will not be released
until the transaction is committed.
- So there is a deadlock.
As a solution, we commit the current transaction in case of VACUUM after
the VACUUM is executed for the shell table. Executing the VACUUM on a
shell table is not important because the data there will probably be
truncated. PostprocessVacuumStmt takes the necessary locks on the shell
table so we don't need to take any extra locks after we commit the
current transaction.
The prepare for upgrade script creates the `'public.pg_dist_rebalance_strategy` table which is not dropped when the upgrade is finished. This may block future upgrades.
In our test structure, we have been passing postgres configurations from
the terminal, which causes problems after it hits to a certain length
hence it cannot start the server and understanding why it failed is not
easy because there isn't a nice error message.
This commit changes this to write the settings directly to the postgres
configuration file. This way we can add as many postgres settings as we
want to without needing to worry about the length problem.
Multi-row & router INSERT's were crashing with local execution if at
least one of the DEFAULT columns were not specified in VALUES list.
This was because, the changes we make on query->values_lists and
query->targetList was sufficient for deparsing given INSERT for remote
execution but not sufficient for local execution.
With this commit, DEFAULT value normalization for multi-row & router
INSERT's is fixed by adding dummy column references for unspecified
DEFAULT columns.
Citus has the logic to truncate the long shard names to prevent
various issues, including self-deadlocks. However, for partitioned
tables, when index is created on the parent table, the index names
on the partitions are auto-generated by Postgres. We use the same
Postgres function to generate the index names on the shards of the
partitions. If the length exceeds the limit, we switch to sequential
execution mode.
In postmasters execution of _PG_init, IsUnderPostmaster will be false and
we want to do the cleanup at that time only, otherwise there is a chance that
there will be parallel queries and we might do a cleanup for things that are
already in use.
Önder Kalacı
Onder Kalaci
Marco Slot
Marco Slot
SaitTalhaNisanci
Simon Kelly
Onur Tirtir
Halil Ozan Akgül
Jelte Fennema
Metin Döşlü
Ahmet Gedemenli
Hanefi Onaldi