This implements the phase - II of MERGE sql support
Support routable query where all the tables in the merge-sql are distributed, co-located, and both the source and
target relations are joined on the distribution column with a constant qual. This should be a Citus single-task
query. Below is an example.
SELECT create_distributed_table('t1', 'id');
SELECT create_distributed_table('s1', 'id', colocate_with => ‘t1’);
MERGE INTO t1
USING s1 ON t1.id = s1.id AND t1.id = 100
WHEN MATCHED THEN
UPDATE SET val = s1.val + 10
WHEN MATCHED THEN
DELETE
WHEN NOT MATCHED THEN
INSERT (id, val, src) VALUES (s1.id, s1.val, s1.src)
Basically, MERGE checks to see if
There are a minimum of two distributed tables (source and a target).
All the distributed tables are indeed colocated.
MERGE relations are joined on the distribution column
MERGE .. USING .. ON target.dist_key = source.dist_key
The query should touch only a single shard i.e. JOIN AND with a constant qual
MERGE .. USING .. ON target.dist_key = source.dist_key AND target.dist_key = <>
If any of the conditions are not met, it raises an exception.
citus_job_list() lists all background jobs by simply showing the records
in pg_dist_background_job.
citus_job_status(job_id bigint, raw boolean default false) shows the
status of a single background job by appending a jsonb details column to
the associated row from pg_dist_background_job. If the raw argument is
set, machine readable sizes are used instead of human readable
alternatives.
citus_rebalance_status(raw boolean default false) shows the status of
the last rebalance operation. If the raw argument is set, machine
readable sizes are used instead of human readable alternatives.
The original implementation of GPIDs didn't work correctly when using
`pg_dist_poolinfo` together with PgBouncer. The reason is that it
assumed that once a connection was made to a worker, the originating
GPID should stay the same for ever. But when pg_dist_poolinfo is used
this isn't the case, because the same connection on the worker might be
used by different backends of the coordinator.
This fixes that issue by updating the GPID whenever a new application
name is set on a connection. This is the only thing that's needed,
because PgBouncer already sets the application name correctly on the
server connection whenever a client is updated.
DESCRIPTION: Enable adding CHECK constraints on distributed tables
without the client having to provide a constraint name.
This PR enables the following command syntax for adding check
constraints to distributed tables.
ALTER TABLE ... ADD CHECK ...
by creating a default constraint name and transforming the command into
the below syntax before sending it to workers.
ALTER TABLE ... ADD CONSTRAINT \<conname> CHECK ...
DESCRIPTION: Introduce citus_copy_shard_placement UDF with node id
DESCRIPTION: Introduce citus_move_shard_placement UDF with node id
DESCRIPTION: Use new shard transfer functions with node id for rebalancing
New shard transfer functions to be used with nodeid instead of hostname
and port.
Use these functions in shard rebalancer.
Table Constraints UNIQUE, PRIMARY KEY and EXCLUDE may have option
DEFERRABLE in their command syntax. This PR handles the option when
deparsing the relevant constraint statements.
NOT DEFERRABLE
and
INITIALLY IMMEDIATE (if DEFERRABLE}
are the default values for the option so we only append the non-default
values to the alter table statement.
In #6412 I made a change to not re-assign the global PID if it was
already set. This inadvertently introduced a regression where `userId`
and `databaseId` would not be set on the backend data when the global
PID was assigned in the authentication hook.
This fixes it by doing two things:
1. Removing `userId` from `BackendData`, since it's not used anywhere
anyway.
2. Move assignment of `databaseId` to dedicated
`SetBackendDataDatabaseId` function, that isn't a no-op when global
pid is already set.
Since #6412 is not released yet this does not need a description.
In #6598 it was noticed that Citus could generate syntactically invalid
statements during logical replication. With #6603 we resolved the direct
issue, by only generating valid subscription names. But there was also
the underlying problem that we did not escape certain identifier
strings. While in theory this should be okay since we should only
generate names that are valid, this issue reiterated that we should not
take this for granted. As an extra line of defense this quotes all
identifiers we use during logical replication setup.
Apparently no-one actually ran the mx_base_schedule, because the tests
in schedule itself were already failing. This updates it to be in line
with multi_mx_schedule again to make the tests pass again. Notably it
doesn't contain multi_mx_node_metadata and multi_extension. Because
those tests take long to run and the were not necessary to make
multi_mx_create_table pass again.
DESCRIPTION: Adds support for creating table constraints UNIQUE and
EXCLUDE via ALTER TABLE command without client having to specify a name.
ALTER TABLE ... ADD CONSTRAINT <conname> UNIQUE ...
ALTER TABLE ... ADD CONSTRAINT <conname> EXCLUDE ...
commands require the client to provide an explicit constraint name.
However, in postgres it is possible for clients not to provide a name
and let the postgres generate it using the following commands
ALTER TABLE ... ADD UNIQUE ...
ALTER TABLE ... ADD EXCLUDE ...
This PR enables the same functionality for citus tables.
DESCRIPTION: Drop `SHARD_STATE_TO_DELETE` and use the cleanup records
instead
Drops the shard state that is used to mark shards as orphaned. Now we
insert cleanup records into `pg_dist_cleanup` so "orphaned" shards will
be dropped either by maintenance daemon or internal cleanup calls. With
this PR, we make the "cleanup orphaned shards" functions to be no-op, as
they would not be needed anymore.
This PR includes some naming changes about placement functions. We don't
need functions that filter orphaned shards, as there will be no orphaned
shards anymore.
We will also be introducing a small script with this PR, for users with
orphaned shards. We'll basically delete the orphaned shard entries from
`pg_dist_placement` and insert cleanup records into `pg_dist_cleanup`
for each one of them, during Citus upgrade.
We also have a lot of flakiness fixes in this PR.
Co-authored-by: Jelte Fennema <github-tech@jeltef.nl>
Sometimes our `isolation_insert_vs_vacuum` test would fail like this.
```diff
step s2-vacuum-analyze:
VACUUM ANALYZE test_insert_vacuum;
-
+ <waiting ...>
step s1-commit:
COMMIT;
+step s2-vacuum-analyze: <... completed>
```
The reason seems to be that VACUUM ANALYZE tries to take some locks that
conflict with the other transaction, but these locks somehow get
released or VACUUM ANALYZE stops waiting for them. This is somewhat
expected since VACUUM has some special locking logic.
To solve the flakyness we now trigger VACUUM ANALYZE to always report as
blocking and after that we wait explicitly wait for it to complete. This
is done
like is suggested by the flaky test tips from postgres:
c68a183990/src/test/isolation/README (L152)
I've confirmed that this fixes the issue suing our flaky-test-debugging
CI workflow.
DESCRIPTION: Defers cleanup after a failure in shard move or split
We don't need to do a cleanup in case of failure on a shard transfer or
split anymore. Because,
* Maintenance daemon will clean them up anyway.
* We trigger a cleanup at the beginning of shard transfers/splits.
* The cleanup on failure logic also can fail sometimes and instead of
the original error, we throw the error that is raised by the cleanup
procedure, and it causes confusion.
* Skip some exceptional test files in the flaky workflow, like
multi_extension
* Run some tests without a schedule, like single_node_enterprise
* Use minimal schedule for the tests in split and operations schedules
DESCRIPTION: Cleanup the shard on the target node in case of a
failed/aborted shard move
Inserts a cleanup record for the moved shard placement on the target
node. If the move operation succeeds, the record will be deleted. If
not, it will remain there to be cleaned up later.
fixes: #6580
* Drop enterprise_split_schedule as it's not even called in our CI
pipeline. It's actually a subset of split_schedule, except for
`citus_split_shard_by_split_points_deferred_drop`. Added that one into
split_schedule and dropped the enterprise one.
* Delete `citus_non_blocking_shard_split_cleanup.out`, as there is no
sql file for it. It seems it's renamed to some other test and the sql
file is deleted, but we forgot to delete the output file.
* 6 test files are chained to each other with dependent objects. Unified
them into one test file so that the flaky check will not fail for them
anymore.
* Some cleanup lines to prevent the flakiness check from failing.
We have several version checks in our Citus upgrade tests. However, as
we drop support for PG versions, we need to update the Citus versions
used in our CI images. Therefore we must compare Citus versions in our
tests instead of using equality checks so that the queries are ran in
all the associated Citus versions.
For example, we have many conditionals where we early exit if the Citus
version is not equal to 9.0. However, as of today we never use version
9.0 and thus we always early exit in those tests.
All the tables (target, source or any CTE present) in the SQL statement are local i.e. a merge-sql with a combination of Citus local and
Non-Citus tables (regular Postgres tables) should work and give the same result as Postgres MERGE on regular tables. Catch and throw an
exception (not-yet-supported) for all other scenarios during Citus-planning phase.
DESCRIPTION: Support ALTER TABLE .. ADD PRIMARY KEY ... command
Before processing
> **ALTER TABLE ... ADD PRIMARY KEY ...**
command
1. Create a primary key name to use as the constraint name.
2. Change the **ALTER TABLE ... ADD PRIMARY KEY ...** command to into
**ALTER TABLE ... ADD CONSTRAINT \<constraint name> PRIMARY KEY ...**
form.
This is the only form we can specify a name for a primary key. If we run
ALTER TABLE .. ADD PRIMARY KEY, postgres
would create a constraint name internally in its own scheme. But the
problem is that we need to create constraint names
for shards in our own scheme which is \<constraint name>_\<shardid>.
Hence we need to create a name and send it to workers so that the
workers can append the shardid.
4. Run the changed command on the coordinator to make sure we are using
the same constraint name across the board.
5. Send the changed command to workers such that it is executed for the
main table as well as for the shards.
Fixes#6515.
Removes unused job boundary tag `SUBQUERY_MAP_MERGE_JOB`.
Only usage is at `BuildMapMergeJob`, which is only called when the
boundary = `JOIN_MAP_MERGE_JOB`. Hence, it should be safe to remove.
Fixes#6501
Before this commit, we created an additional WaitEventSet for
checking whether the remote socket is closed per connection -
only once at the start of the execution.
However, for certain workloads, such as pgbench select-only
workloads, the creation/deletion of the additional WaitEventSet
adds ~7% CPU overhead, which is also reflected on the benchmark
results.
With this commit, we use the same WaitEventSet for the purposes
of checking the remote socket at the start of the execution.
We use "rebuildWaitEventSet" flag so that the executor can re-use
the existing WaitEventSet.
As a result, we see the following improvements on PG 15:
main : 120051 tps, 0.532 ms latency avg.
avoid_wes_rebuild: 127119 tps, 0.503 ms latency avg.
And, on PG 14, as expected, there is no difference
main : 129191 tps, 0.495 ms latency avg.
avoid_wes_rebuild: 129480 tps, 0.494 ms latency avg.
But, note that PG 15 is slightly (~1.5%) slower than PG 14.
That is probably the overhead of checking the remote socket.
Before this commit, we created an additional WaitEventSet for
checking whether the remote socket is closed per connection -
only once at the start of the execution.
However, for certain workloads, such as pgbench select-only
workloads, the creation/deletion of the additional WaitEventSet
adds ~7% CPU overhead, which is also reflected on the benchmark
results.
With this commit, we use the same WaitEventSet for the purposes
of checking the remote socket at the start of the execution.
We use "rebuildWaitEventSet" flag so that the executor can re-use
the existing WaitEventSet.
As a result, we see the following improvements on PG 15:
main : 120051 tps, 0.532 ms latency avg.
avoid_wes_rebuild: 127119 tps, 0.503 ms latency avg.
And, on PG 14, as expected, there is no difference
main : 129191 tps, 0.495 ms latency avg.
avoid_wes_rebuild: 129480 tps, 0.494 ms latency avg.
But, note that PG 15 is slightly (~1.5%) slower than PG 14.
That is probably the overhead of checking the remote socket.
Fixes a missed include in #6315.
While adding the cluster clock we have added some extra steps to
`citus_prepare_pg_upgrade` and `citus_finish_pg_upgrade`. These changes
were not added to the citus upgrade and downgrade scripts, this allowed
for a syntax error to slip in.
This PR adds the new versions of both UDF's to the upgrade script while
adding the old version to the downgrade script. This exposed the syntax
error which is also solved.
- Because of the make command used for vanilla tests, test status is
always shown as success on CI. As a fix, I added `&& false` at the end
of the copying diff file to make the command fail when check-vanilla
fails.
```make
check-vanilla: all
$(pg_regress_multi_check) --vanillatest || (cp $(vanilla_diffs_file) $(citus_abs_srcdir)/regression.diffs && false)
```
- I also fixed some vanilla tests that fails due to recently added clock
related operators shown up at some queries.
Teja Mupparti
Onur Tirtir
Ahmet Gedemenli
Hanefi Onaldi
Jelte Fennema
Marco Slot
Emel Şimşek
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