DESCRIPTION: Adds citus_stat_counters view that can be used to query
stat counters that Citus collects while the feature is enabled, which is
controlled by citus.enable_stat_counters. citus_stat_counters() can be
used to query the stat counters for the provided database oid and
citus_stat_counters_reset() can be used to reset them for the provided
database oid or for the current database if nothing or 0 is provided.
Today we don't persist stat counters on server shutdown. In other words,
stat counters are automatically reset in case of a server restart.
Details on the underlying design can be found in header comment of
stat_counters.c and in the technical readme.
-------
Here are the details about what we track as of this PR:
For connection management, we have three statistics about the inter-node
connections initiated by the node itself:
* **connection_establishment_succeeded**
* **connection_establishment_failed**
* **connection_reused**
While the first two are relatively easier to understand, the third one
covers the case where a connection is reused. This can happen when a
connection was already established to the desired node, Citus decided to
cache it for some time (see citus.max_cached_conns_per_worker &
citus.max_cached_connection_lifetime), and then reused it for a new
remote operation. Here are the other important details about these
connection statistics:
1. connection_establishment_failed doesn't care about the connections
that we could establish but are lost later in the transaction. Plus, we
cannot guarantee that the connections that are counted in
connection_establishment_succeeded were not lost later.
2. connection_establishment_failed doesn't care about the optional
connections (see OPTIONAL_CONNECTION flag) that we gave up establishing
because of the connection throttling rules we follow (see
citus.max_shared_pool_size & citus.local_shared_pool_size). The reaason
for this is that we didn't even try to establish these connections.
3. For the rest of the cases where a connection failed for some reason,
we always increment connection_establishment_failed even if the caller
was okay with the failure and know how to recover from it (e.g., the
adaptive executor knows how to fall back local execution when the target
node is the local node and if it cannot establish a connection to the
local node). The reason is that even if it's likely that we can still
serve the operation, we still failed to establish the connection and we
want to track this.
4. Finally, the connection failures that we count in
connection_establishment_failed might be caused by any of the following
reasons and for now we prefer to _not_ further distinguish them for
simplicity:
a. remote node is down or cannot accept any more connections, or
overloaded such that citus.node_connection_timeout is not enough to
establish a connection
b. any internal Citus error that might result in preparing a bad
connection string so that libpq fails when parsing the connection string
even before actually trying to establish a connection via connect() call
c. broken citus.node_conninfo or such Citus configuration that was
incorrectly set by the user can also result in similar outcomes as in b
d. internal waitevent set / poll errors or OOM in local node
We also track two more statistics for query execution:
* **query_execution_single_shard**
* **query_execution_multi_shard**
And more importantly, both query_execution_single_shard and
query_execution_multi_shard are not only tracked for the top-level
queries but also for the subplans etc. The reason is that for some
queries, e.g., the ones that go through recursive planning, after Citus
performs the heavy work as part of subplans, the work that needs to be
done for the top-level query becomes quite straightforward. And for such
query types, it would be deceiving if we only incremented the query stat
counters for the top-level query. Similarly, for non-pushable INSERT ..
SELECT and MERGE queries, we perform separate counter increments for the
SELECT / source part of the query besides the final INSERT / MERGE
query.
Fixes#7105.
DESCRIPTION: Fixes a bug that causes omitting CASCADE clause for the
commands sent to workers for REVOKE commands on tables.
---------
Co-authored-by: ThomasC02 <thomascantrell02@gmail.com>
Co-authored-by: Onur Tirtir <onurcantirtir@gmail.com>
Co-authored-by: Tiago Silva <tiagos3373@gmail.com>
DESCRIPTION: Adjusts max_prepared_transactions only when it's set to
default on PG >= 16
Fixes#7711.
Change AdjustMaxPreparedTransactions to really check if
max_prepared_transactions is explicitly set by user, and only adjust
max_prepared_transactions when it is default.
This fixes 021_twophase test failure with loaded Citus library after
postgres/postgres@b39c5272.
Co-authored-by: Karina Litskevich <litskevichkarina@gmail.com>
Var externParamPlaceholder is created on stack, and its address is used
for paramFetch. Postgres code return address of externParamPlaceholder
var to externParam, then code flow go out of scope and dereference
pointer on stack out of scope.
Fixes https://github.com/citusdata/citus/issues/7941.
---------
Co-authored-by: Onur Tirtir <onurcantirtir@gmail.com>
Var jobTypeName is created on stack and its value over pointer is used
in heap_form_tuple, so we
have stack use out of scope.
Issue was detected with adress sanitizer.
Fixes#7943.
DESCRIPTION: Makes sure to prevent `INSERT INTO ... SELECT` queries involving subfield or sublink, to avoid crashes
The following query was crashing the backend:
```
INSERT INTO field_indirection_test_1 (
int_col, ct1_col.int_1,ct1_col.int_2
) SELECT 0, 1, 2;
-- crash
```
En passant, added more tests with sublink in distributed_types and found
another query with wrong behavior:
```
INSERT INTO domain_indirection_test (f1,f3.if1) SELECT 0, 1;
ERROR: could not find a conversion path from type 23 to 17619
-- not the expected ERROR
```
Fixed them by using `strip_implicit_coercions()` on target entry
expression before checking for the presence of a subscript or
fieldstore, else we fail to find the existing ones and wrongly accept to
execute unsafe query.
DESCRIPTION: Fixes a bug in deparsing of shard query in case of
"output-table column" name conflict
If an `ORDER BY` item in `SELECT` is a bare identifier, the parser
_first seeks it as an output column name_ of the `SELECT` (for SQL92
compatibility). However, ruleutils.c is expecting the SQL99
interpretation _where such a name is an input column name_. So it's
possible to produce an incorrect display of a view in the (admittedly
pretty ill-advised) case where some other column is renamed in the
`SELECT` output list to match an `ORDER BY` column.
The `DISTINCT ON` expressions are interpreted using the same rules as
for `ORDER BY`.
We had an issue reported that actually uses `DISTINCT ON`: #7684
Since Citus uses ruleutils deparsing logic to create the shard queries,
it would not
table-qualify the column names as needed.
PG17 fixed this https://github.com/postgres/postgres/commit/a7eb633563c
by table-qualifying such names in the dumped view text. Therefore,
Citus doesn't reproduce the issue in PG17, since PG17 table-qualifies
the column names when needed, and the produced shard queries are
correct.
This PR applies the PG17 patch to `ruleutils_15.c` and `ruleutils_16.c`.
Even though we generally try to avoid modifying the ruleutils files, in
this case
we are applying a Postgres patch that `ruleutils_17.c` already has:
897d996b8f
Thanks @c2main for your discussion and idea in the issue.
Fixes#7684
DESCRIPTION: Adds citus_is_primary_node() UDF to determine if the
current node is a primary node in the cluster.
---------
Co-authored-by: German Eichberger <geeichbe@microsoft.com>
Co-authored-by: Onur Tirtir <onurcantirtir@gmail.com>
This commit also has to do with renaming of
daticulocale to datlocale
Relevant PG commit:
f696c0cd5f299f1b51e214efc55a22a782cc175d
f696c0cd5f
Keeping this commit separate from the previous one because
these changes will be different once we drop PG15 support.
For now I renamed pg_ge_15_options to pg_ge_15_17_options
and together with it I changed the meaning of the variable.
However when we drop PG14 support, we will use pg_ge_17_options
and delete pg_ge_15_options altogether
DESCRIPTION: Fixes a bug with `UPDATE SET (...) = (SELECT
some_func(),... )` (#7676)
Citus was checking for presence of sublink, but forgot to manage
multiexpr while evaluating clauses during planning. At this stage (citus
planner), it's not always possible to call PostgreSQL code because the
tree is not yet ready for PostgreSQL pure executor.
Fixes https://github.com/citusdata/citus/issues/7676.
Fixed by adding a new function to check sublink or multiexpr in the
tree.
---------
Co-authored-by: Colm <colmmchugh@microsoft.com>
## Enhance `AddInsertSelectCasts` for Identity Columns
This PR fixes#7887 and improves the behavior of partial inserts into
**identity columns** by modifying the **`AddInsertSelectCasts`**
function. Specifically, we introduce **special-case handling** for
`nextval(...)` calls (represented in the parse tree as `NextValueExpr`)
to ensure that if the identity column’s declared type differs from
`nextval`’s default return type (`int8`), we **cast** the expression
properly. This prevents mismatches like `int8` → `int4` from causing
“invalid string enlargement” errors or other type-related failures.
When `INSERT ... SELECT` is processed, `AddInsertSelectCasts` reconciles
each target column’s type with the corresponding SELECT expression’s
type. Historically, for identity columns that rely on `nextval(...)`, we
can end up with a mismatch:
- `nextval` returns **`int8`**,
- The identity column might be **`int4`**, **`bigint`**, or another
integer type.
Without a correct cast, Postgres or Citus can produce plan-time or
runtime errors. By **detecting** `NextValueExpr` and applying a cast to
the column’s type, the final plan ensures consistent insertion without
errors.
## What Changed
1. **Check for `NextValueExpr`**:
In `AddInsertSelectCasts`, we now have a code block:
```c
if (IsA(selectEntry->expr, NextValueExpr))
{
Oid nextvalType = GetNextvalReturnTypeCatalog();
...
// If (targetType != nextvalType), build a cast from int8 -> targetType
}
else
{
// fallback to generic mismatch logic
}
```
This short-circuits any expression that’s a `nextval(...)` call, letting
us explicitly cast to the correct type.
2. **Fallback Generic Logic**:
If it isn’t a `NextValueExpr` (i.e. a normal column or expression
mismatch), we still rely on the existing path that compares `sourceType`
vs. `targetType` and calls `CastExpr(...)` if they differ.
3. **`GetNextvalReturnTypeCatalog`**:
We added or refined a helper function to confirm that `nextval` returns
`int8`, or do a `LookupFuncName("nextval", ...)` to discover the
function’s return type from `pg_proc`—making it robust if future changes
happen.
## Benefits
- **Partial inserts** into identity columns no longer fail with type
mismatches.
- When `nextval` yields `int8` but the identity column is `int4` (or
another type), we properly cast to the column’s type in the plan.
- Preserves the **existing** approach for other columns—only identity
calls get the specialized `NextValueExpr` logic.
## Testing
- Extended `generatedidentity.sql` test scenario to cover partial
inserts into both `GENERATED ALWAYS` and `GENERATED BY DEFAULT` identity
columns, including tests for the `OVERRIDING SYSTEM VALUE` clause and
partial inserts referencing foreign-key columns.
DESCRIPTION: Fixes deadlock with transaction recovery that is possible
during Citus upgrades.
Fixes#7875.
This commit addresses two interrelated deadlock issues uncovered during Citus
upgrades:
1. Local Deadlock:
- **Problem:**
In `RecoverWorkerTransactions()`, a new connection is created for each worker
node to perform transaction recovery by locking the
`pg_dist_transaction` catalog table until the end of the transaction. When
`RecoverTwoPhaseCommits()` calls this function for each worker node, the order
of acquiring locks on `pg_dist_authinfo` and `pg_dist_transaction` can alternate.
This reversal can lead to a deadlock if any concurrent process requires locks on
these tables.
- **Fix:**
Pre-establish all worker node connections upfront so that
`RecoverWorkerTransactions()` operates with a single, consistent connection.
This ensures that locks on `pg_dist_authinfo` and `pg_dist_transaction` are always
acquired in the correct order, thereby preventing the local deadlock.
2. Distributed Deadlock:
- **Problem:**
After resolving the local deadlock, a distributed deadlock issue emerges. The
maintenance daemon calls `RecoverWorkerTransactions()` on each worker node—
including the local node—which leads to a complex locking sequence:
- A RowExclusiveLock is taken on the `pg_dist_transaction` table in
`RecoverWorkerTransactions()`.
- An update extension then tries to acquire an AccessExclusiveLock on the same
table, getting blocked by the RowExclusiveLock.
- A subsequent query (e.g., a SELECT on `pg_prepared_xacts`) issued using a
separate connection on the local node gets blocked due to locks held during a
call to `BuildCitusTableCacheEntry()`.
- The maintenance daemon waits for this query, resulting in a circular wait and
stalling the entire cluster.
- **Fix:**
Avoid cache lookups for internal PostgreSQL tables by implementing an early bailout
for relation IDs below `FirstNormalObjectId` (system objects). This eliminates
unnecessary calls to `BuildCitusTableCache`, reducing lock contention and mitigating
the distributed deadlock.
Furthermore, this optimization improves performance in fast
connect→query_catalog→disconnect cycles by eliminating redundant
cache creation and lookups.
3. Also reverts the commit that disabled the relevant test cases.
DESCRIPTION: fix a planning error caused by a redundant WHERE clause
Fix a Citus planning glitch that occurs in a DML query when the WHERE
clause of the query is of the form:
` WHERE true OR <expression with 1 or more citus tables> `
and this is the only place in the query referencing a citus table.
Postgres' standard planner transforms the WHERE clause to:
` WHERE true `
So the query now has no citus tables, confusing the Citus planner as
described in issues #7782 and #7783. The fix is to check, after Postgres
standard planner, if the Query has been transformed as shown, and re-run
the check of whether or not the query needs distributed planning.
This PR fixes an issue #7891 in the Citus planner where an `UPDATE` on a
local table with a subquery referencing a reference table could produce
a 0-task plan. Historically, the planner sometimes failed to detect that
both the target and referenced tables were effectively “local,”
assigning `INVALID_SHARD_ID `and yielding a no-op plan.
### Root Cause
- In the Citus router logic (`PlanRouterQuery`), we relied on `shardId`
to determine whether a query should be routed to a single shard.
- If `shardId == INVALID_SHARD_ID`, but we also had not marked the query
as a “local table modification,” the code path would produce zero tasks.
- Local + reference tables do not require multi-shard routing. Failing
to detect this “purely local” scenario caused Citus to incorrectly route
to zero tasks.
### Changes
**Enhanced Local Table Detection**
- Updated `IsLocalTableModification` and related checks to consider both
local and reference tables as “local” for planning, preventing the
0-task scenario.
- Expanded `ContainsOnlyLocalOrReferenceTables` to return true if there
are no fully distributed tables in the query.
**Added Regress Test**
- Introduced a new regress test (`issue_7891.sql`) which reproduces the
scenario.
- Verifies we get a valid single- or local-task plan rather than a
0-task plan.
DESCRIPTION: Ensure that a MERGE command on a distributed table with a
`WHEN NOT MATCHED BY SOURCE` clause runs against all shards of the
distributed table.
The Postgres MERGE command updates a table using a table or a query as a
data source. It provides three ways to match the target table with the
source: `WHEN MATCHED` means that there is a row in both the target and
source; `WHEN NOT MATCHED` means that there is a row in the source that
has no match (is not present) in the target; and, as of PG17, `WHEN NOT
MATCHED BY SOURCE` means that there is a row in the target that has no
match in the source.
In Citus, when a MERGE command updates a distributed table using a
local/reference table or a distributed query as source, that source is
repartitioned, and for each repartitioned shard that has data (i.e. 1 or
more rows) the MERGE is run against the corresponding distributed table
shard. Suppose the distributed table has 32 shards, and the source
repartitions into 4 shards that have data, with the remaining 28 shards
being empty; then the MERGE command is performed on the 4 corresponding
shards of the distributed table. However, the semantics of `WHEN NOT
MATCHED BY SOURCE` are that the specified action must be performed on
the target for each row in the target that is not in the source; so if
the source is empty, all target rows should be updated. To see this,
consider the following MERGE command:
```
MERGE INTO target AS t
USING source AS s ON t.id = s.id
WHEN NOT MATCHED BY SOURCE THEN UPDATE t SET t.col1 = 100
```
If the source has zero rows then every row in the target is updated s.t.
its col1 value is 100. Currently in Citus a MERGE on a distributed table
with a local/reference table or a distributed query as source ignores
shards of the distributed table when the corresponding shard of the
repartitioned source has zero rows. However, if the MERGE command
specifies a `WHEN NOT MATCHED BY SOURCE` clause, then the MERGE should
be performed on all shards of the distributed table, to ensure that the
specified action is performed on the target for each row in the target
that is not in the source. This PR enhances Citus MERGE execution so
that when a repartitioned source shard has zero rows, and the MERGE
command specifies a `WHEN NOT MATCHED BY SOURCE` clause, the MERGE is
performed against the corresponding shard of the distributed table using
an empty (zero row) relation as source, by generating a query of the
form:
```
MERGE INTO target_shard_0002 AS t
USING (SELECT id FROM (VALUES (NULL) ) source_0002(id) WHERE FALSE) AS s ON t.id = s.id
WHEN NOT MATCHED BY SOURCE THEN UPDATE t set t.col1 = 100
```
This works because each row in the target shard will be updated, and
`WHEN MATCHED` and `WHEN NOT MATCHED`, if specified, will be no-ops
because the source has zero rows.
To implement this when the source is a local or reference table involves
teaching function `ExcuteSourceAtCoordAndRedistribution()` in
`merge_executor.c` to not prune tasks when the query has `WHEN NOT
MATCHED BY SOURCE` but to instead replace the task's query to one that
uses an empty relation as source. And when the source is a distributed
query, function
`ExecuteMergeSourcePlanIntoColocatedIntermediateResults()` (also in
`merge_executor.c`) instead of skipping empty tasks now generates a
query that uses an empty relation as source for the corresponding target
shard of the distributed table, but again only when the query has `WHEN
NOT MATCHED BY SOURCE`. A new function `BuildEmptyResultQuery()` is
added to `recursive_planning.c` and it is used by both the
aforementioned functions in `merge_executor.c` to build an empty
relation to use as the source. It applies the appropriate type to each
column of the empty relation so the join with the target makes sense to
the query compiler.
DESCRIPTION: Fixes a crash in columnar custom scan that happens when a
columnar table is used in a join. Fixes issue #7647.
Co-authored-by: Ольга Сергеева <ob-sergeeva@it-serv.ru>
DESCRIPTION: Fixes a crash in left outer joins that can happen when
there is an an aggregate on a column from the inner side of the join.
Fix the SEGV seen in #7787 and #7899; it occurs because a column in the
targetlist of a worker subquery can contain a non-empty varnullingrels
field if the column is from the inner side of a left outer join. The
issue can also occur with the columns in the HAVING clause, and this is
also tested in the fix. The issue was triggered by the introduction of
the varnullingrels to Vars in Postgres 16 (2489d76c)
There is a related issue, #7705, where a non-empty varnullingrels was
incorrectly copied into the query tree for the combine query. Here, a
non-empty varnullingrels field of a var is incorrectly copied into the
query tree for a worker subquery.
The regress file from #7705 is used (and renamed) to also test this
(#7787). An alternative test output file is required for Postgres 15
because of an optimization to DISTINCT in Postgres 16 (1349d2790bf).
DESCRIPTION: Drops PG14 support
1. Remove "$version_num" != 'xx' from configure file
2. delete all PG_VERSION_NUM = PG_VERSION_XX references in the code
3. Look at pg_version_compat.h file, remove all _compat functions etc
defined specifically for PGXX differences
4. delete all PG_VERSION_NUM >= PG_VERSION_(XX+1), PG_VERSION_NUM <
PG_VERSION_(XX+1) ifs in the codebase
5. delete ruleutils_xx.c file
6. cleanup normalize.sed file from pg14 specific lines
7. delete all alternative output files for that particular PG version,
server_version_ge variable helps here
As of this commit, after recovering the remote transactions, now we release the lock
on pg_dist_transaction while closing it to avoid deadlocks that might occur because
of trying to acquire a lock on pg_dist_authinfo while holding a lock on
pg_dist_transaction. Such a scenario can only cause a deadlock if another transaction
is trying to acquire a strong lock on pg_dist_transaction while holding a lock on
pg_dist_authinfo. As of today, we (implicitly) acquire a strong lock on
pg_dist_transaction only when upgrading Citus to 11.3-1 and this happens when creating
a REPLICA IDENTITY on pg_dist_transaction.
And regardless of the code-path we are in, it should be okay to release the lock there
because all we do after that point is to abort the prepared transactions that are not
part of an in-progress distributed transaction and releasing the lock before doing so
should be just fine.
This also changes the blocking behavior between citus_create_restore_point and the
transaction recovery code-path in the sense that now citus_create_restore_point doesn't
until transaction recovery completes aborting the prepared transactions that are not
part of an in-progress distributed transaction. However, this should be fine because
even before this was possible, e.g., if transaction recovery fails to open a remote
connection to a node.
This pull request addresses Issue #7846, where specific MERGE queries on
non-distributed and distributed tables can result in crashes in certain
scenarios. The issue stems from the usage of `pg_class` catalog table,
and the `FilterShardsFromPgclass` function in Citus. This function goes
through the query's jointree to hide the shards. However, in PG17,
MERGE's join quals are in a separate structure called
`mergeJoinCondition`. Therefore FilterShardsFromPgclass was not
filtering correctly in a `MERGE` command that involves `pg_class`. To
fix the issue, we handle `mergeJoinCondition` separately in PG17.
Relevant PG commit:
0294df2f1f
**Non-Distributed Tables:**
A MERGE query involving a non-distributed table using
`pg_catalog.pg_class` as the source may execute successfully but needs
testing to ensure stability.
**Distributed Tables:**
Performing a MERGE on a distributed table using `pg_catalog.pg_class` as
the source raises an error:
`ERROR: MERGE INTO a distributed table from Postgres table is not yet
supported`
However, in some cases, this can lead to a server crash if the
unsupported operation is not properly handled.
This is the test output from the same test conducted prior to the code
changes being implemented.
```
-- Issue #7846: Test crash scenarios with MERGE on non-distributed and distributed tables
-- Step 1: Connect to a worker node to verify shard visibility
\c postgresql://postgres@localhost::worker_1_port/regression?application_name=psql
SET search_path TO pg17;
-- Step 2: Create and test a non-distributed table
CREATE TABLE non_dist_table_12345 (id INTEGER);
-- Test MERGE on the non-distributed table
MERGE INTO non_dist_table_12345 AS target_0
USING pg_catalog.pg_class AS ref_0
ON target_0.id = ref_0.relpages
WHEN NOT MATCHED THEN DO NOTHING;
SSL SYSCALL error: EOF detected
connection to server was lost
```
Regress test tdigest_aggregate_support has been failing since at least
Citus 12.0, when tdigest extension is installed in Postgres. This
appears to be because of an omission by commit 03832f3 and a change in
the implementation of Postgres random() function (pg commit
[d4f109e4a](https://git.postgresql.org/gitweb/?p=postgresql.git;a=commitdiff;h=d4f109e4a)).
To reproduce the test diff:
- Checkout [tdigest ](https://github.com/tvondra/tdigest)and run `make;
make install`
- In citus regress directory run `make check-multi` or
`./citus_tests/run_test.py tdigest_aggregate_support`
There are two parts to this commit:
1. Revert `Output: xxxxx` in EXPLAIN VERBOSE. Citus commit fe4ac51
normalized EXPLAIN VERBOSE output because of a change between pg12 and
pg13. When pg12 support was no longer required, the rule was removed
from normalize.sed and `Output: xxxx` was reverted in the impacted
regress output files (03832f3), but `tdigest_aggregate_support` was
omitted.
2. Adjust the query results; the tdigest_aggregate_support test file has
a comment _verifying results - should be stable due to seed while
inserting the data, if failure due to data these queries could be
removed or check for certain ranges_ but the result values in this
commit are consistent across citus 12.0 (pg 15), citus 12.1 (pg 16) and
citus 13.0 (pg 17), or since the Postgres changed their [implementation
of
random](https://git.postgresql.org/gitweb/?p=postgresql.git;a=commitdiff;h=d4f109e4a),
so proposing to go with these results.
DESCRIPTION: Propagates MERGE ... WHEN NOT MATCHED BY SOURCE
It seems like there is not much needed to be done here.
`get_merge_query_def` from `ruleutils_17` is updated with "WHEN NOT
MATCHED BY SOURCE" therefore `deparse_shard_query` parses the merge
query for execution on the shard correctly.
Relevant PG commit:
https://github.com/postgres/postgres/commit/0294df2f1
DESCRIPTION: Propagates MEMORY and SERIALIZE options of EXPLAIN
The options for `MEMORY` can be true or false. Default is false.
The options for `SERIALIZE` can be none, text or binary. Default is
none.
I referred to how we added support for WAL option in this PR [Support
EXPLAIN(ANALYZE, WAL)](https://github.com/citusdata/citus/pull/4196).
For the tests however, I used the same tests as Postgres, not like the
tests in the WAL PR. I used exactly the same tests as Postgres does, I
simply distributed the table beforehand. See below the relevant Postgres
commits from where you can see the tests added as well:
- [Add EXPLAIN
(MEMORY)](https://github.com/postgres/postgres/commit/5de890e36)
- [Invent SERIALIZE option for
EXPLAIN.](https://github.com/postgres/postgres/commit/06286709e)
This PR required a lot of copying of Postgres static functions regarding
how `EXPLAIN` works for `MEMORY` and `SERIALIZE` options. Specifically,
these copy-pastes were required for updating `ExplainWorkerPlan()`
function, which is in fact based on postgres' `ExplainOnePlan()`:
```C
/* copied from explain.c to update ExplainWorkerPlan() in citus according to ExplainOnePlan() in postgres */
#define BYTES_TO_KILOBYTES(b)
typedef struct SerializeMetrics
static bool peek_buffer_usage(ExplainState *es, const BufferUsage *usage);
static void show_buffer_usage(ExplainState *es, const BufferUsage *usage);
static void show_memory_counters(ExplainState *es, const MemoryContextCounters *mem_counters);
static void ExplainIndentText(ExplainState *es);
static void ExplainPrintSerialize(ExplainState *es, SerializeMetrics *metrics);
static SerializeMetrics GetSerializationMetrics(DestReceiver *dest);
```
_Note_: it looks like we were missing some `buffers` option details as
well. I put them together with the memory option, like the code in
Postgres explain.c, as I didn't want to change the copied code. However,
I tested locally and there is no big deal in previous Citus versions,
and you can also see that existing Citus tests with `buffers true`
didn't change. Therefore, I prefer not to backport "buffers" changes to
previous versions.
This PR adds regression tests to verify REINDEX support with event
triggers. Tests validates trigger execution, shard placement
consistency, and distributed index rebuilding without disruption.
This PR adds a regression test to verify the behavior of access methods
for partitioned and distributed tables, including:
- Creating partitioned tables with heap.
- Distributing tables using create_distributed_table.
- Switching access methods to columnar with ALTER TABLE.
- Validating access method inheritance for new partitions.
Relecant PG17 commit: https://github.com/postgres/postgres/commit/374c7a229
DESCRIPTION: Adds JSON_TABLE() support
PG17 has added basic `JSON_TABLE()` functionality
`JSON_TABLE()` allows `JSON` data to be converted into a relational view
and thus used, for example, in a `FROM` clause, like other tabular data.
We treat `JSON_TABLE` the same as correlated functions (e.g., recurring
tuples). In the end, for multi-shard `JSON_TABLE` commands, we apply the
same restrictions as reference tables (e.g., cannot perform a lateral
outer join when a distributed subquery references a (reference
table)/(json table) etc.)
Relevant PG17 commits:
[basic JSON
table](https://github.com/postgres/postgres/commit/de3600452), [nested
paths in json
table](https://github.com/postgres/postgres/commit/bb766cde6)
Onder had previously added json table support for PG15BETA1, but we
reverted that commit because json table was reverted in PG15.
ce7f1a530f
Previous relevant PG15Beta1 commit:
https://github.com/postgres/postgres/commit/4e34747c8
Therefore, I referred to Onder's commit for this commit as well, with a
few changes due to some differences between PG15/PG17:
1) In PG15Beta1, we had also `PLAN` clauses for `JSON_TABLE`
https://github.com/postgres/postgres/commit/fadb48b00, and Onder's
commit includes tests for those as well. However, `PLAN` nodes are _not_
added in PG17. Therefore, I didn't include the `json_table_select_only`
test, which had mostly queries involving `PLAN`. I only included the
last query from that test.
2) In PG15 timeline (Citus 11.1), we didn't support outer joins where
the outer rel is a recurring one and the inner one is a non-recurring
one. However, [Onur added support for that one in Citus
11.2](https://github.com/citusdata/citus/pull/6512), therefore I updated
the tests from Onder's commit accordingly.
3) PG17 json table has nested paths and columns, therefore I added a
test
with a distributed table, which is exactly the same as the one in
sqljson_jsontable in PG17.
https://github.com/postgres/postgres/commit/bb766cde6
This pull request also adds some basic tests on validation of SQL/JSON
constructor functions JSON(), JSON_SCALAR(), and JSON_SERIALIZE(),
and also SQL/JSON query functions JSON_EXISTS(), JSON_QUERY(), and
JSON_VALUE(). The relevant PG commits are the following:
[JSON(), JSON_SCALAR(),
JSON_SERIALIZE()](https://github.com/postgres/postgres/commit/03734a7fe)
[JSON_EXISTS(), JSON_VALUE(),
JSON_QUERY()](https://github.com/postgres/postgres/commit/6185c9737)
PG17 has added support for AT LOCAL operator
it converts the given time type to
time stamp with the session's TimeZone value as time zone. Here we add
tests that validate that we can use AT LOCAL at INSERT commands
Relevant PG commit:
https://github.com/postgres/postgres/commit/97957fdba
With the tests, we verify that we evaluate AT LOCAL at the coordinator
and then perform the insert remotely.
PG17 added support for
ALTER TABLE ... ALTER COLUMN ... SET EXPRESSION.
Relevant PG commit: https://github.com/postgres/postgres/commit/5d06e99a3
We currently don't support propagating this command for Citus tables.
It is added to future work.
This PR disallows `ALTER TABLE ... ALTER COLUMN ... SET EXPRESSION` on
all Citus table types (local, distributed, and partitioned distributed)
by adding an error check in `ErrorIfUnsupportedAlterTableStmt`. A new
regression test verifies that each table type fails with a consistent
error message when attempting to set an expression.
PG17 introduced ALTER TABLE ... SET ACCESS METHOD DEFAULT
This PR introduces and enforces an error check preventing ALTER TABLE
... SET ACCESS METHOD DEFAULT on both Citus local tables (added via
citus_add_local_table_to_metadata) and distributed/partitioned
distributed tables. The regression tests now demonstrate that each table
type raises an error advising users to explicitly specify an access
method, rather than relying on DEFAULT. This ensures consistent behavior
across local and distributed environments in Citus.
The reason why we currently don't support this is that we can't simply
propagate the command as it is, because the default table access method
may be different across Citus cluster nodes.
Relevant PG commit:
https://github.com/postgres/postgres/commit/d61a6cad6
These options already existed in PG17, and we support them and have
tests for them in `multi_copy.sql`.
In PG17, their capability was extended to specify ALL columns at once
using *.
Citus performs the COPY correctly, as is validated by the added tests in
this PR.
Relevant PG commit:
https://github.com/postgres/postgres/commit/f6d4c9cf1
Copy-pasting from Postgres documentation what these options do, such
that the reviewer may better understand the tests added:
`FORCE_NOT_NULL`: Do not match the specified columns' values against the
null string. In the default case where the null string is empty, this
means that empty values will be read as zero-length strings rather than
nulls, even when they are not quoted. If * is specified, the option will
be applied to all columns. This option is allowed only in `COPY FROM`,
and only when using `CSV` format.
`FORCE_NULL`: Match the specified columns' values against the null
string, even if it has been quoted, and if a match is found set the
value to `NULL`. In the default case where the null string is empty,
this converts a quoted empty string into `NULL`. If * is specified, the
option will be applied to all columns. This option is allowed only in
`COPY FROM`, and only when using `CSV` format.
`FORCE_NULL` and `FORCE_NOT_NULL` can be used simultaneously on the same
column. This results in converting quoted null strings to null values
and unquoted null strings to empty strings.
Explain it to me like I'm a 5-year-old, for a text column:
`FORCE_NULL` looks for empty strings and registers them as `NULL`
`FORCE_NOT_NULL` looks for null values and registers them as empty
strings.
PG17 added the new ON_ERROR option for COPY FROM. When this option is
specified, COPY skips soft errors and
continues copying.
Relevant PG commits:
-- https://github.com/postgres/postgres/commit/9e2d87011
-- https://github.com/postgres/postgres/commit/b725b7eec
I tried it locally with Citus tables.
Without further implementation, it doesn't work correctly.
Therefore, we error out for now, and add it to future work.
PG17 also added log_verbosity option, which controls the
amount of messages emitted during processing. This is
currently used in COPY FROM when ON_ERROR option is set to
ignore. Therefore, we error out for this option as well.
Relevant PG17 commit:
https://github.com/postgres/postgres/commit/f5a227895
DESCRIPTION: Propagates ALTER INDEX ALTER COLUMN SET STATISTICS DEFAULT
We automatically support this. Adding tests only.
We currently don't support ALTER TABLE ALTER COLUMN SET STATISTICS
Relevant PG commit:
https://github.com/postgres/postgres/commit/4f622503d
We are using `release-13.0` branch for both development and release, to
deliver PG17 support in Citus.
Afterwards, we will (probably) merge this branch into main.
Some potential changes for main branch, after we are done working on
release-13.0:
- Merge changes from `release-13.0` to `main`
- Figure out what changes were there on 12.2, move them to 13.1 version.
In a nutshell: rename `12.1--12.2` to `13.0--13.1` and fix issues.
- Set version to 13.1devel
In earlier versions of PostgreSQL, exclusion constraints were not
allowed on partitioned tables. This is why the error in your regression
test (ERROR: exclusion constraints are not supported on partitioned
tables) was raised in PostgreSQL 16. In PostgreSQL 17, exclusion
constraints are now allowed on partitioned tables, which is why the
error no longer appears when you attempt to add an exclusion constraint.
The constraint exclusion mechanism, described in the documentation,
relies on CHECK constraints to decide which partitions or child tables
need to be queried.
[CHECK
constraints](https://www.postgresql.org/docs/current/ddl-partitioning.html#DDL-PARTITIONING-CONSTRAINT-EXCLUSION)
```diff
-- Check "ADD EXCLUDE" errors out for partitioned table since the postgres does not allow it
ALTER TABLE AT_AddConstNoName.citus_local_partitioned_table ADD EXCLUDE(partition_col WITH =);
-ERROR: exclusion constraints are not supported on partitioned tables
-- Check "ADD CHECK"
SET client_min_messages TO DEBUG1;
ALTER TABLE AT_AddConstNoName.citus_local_partitioned_table ADD CHECK (dist_col > 0);
DEBUG: the constraint name on the shards of the partition is too long, switching to sequential and local execution mode to prevent self deadlocks: longlonglonglonglonglonglonglonglonglonglonglo_537570f5_5_check
DEBUG: verifying table "longlonglonglonglonglonglonglonglonglonglonglonglonglonglongabc"
DEBUG: verifying table "p1"
RESET client_min_messages;
SELECT con.conname
FROM pg_catalog.pg_constraint con
INNER JOIN pg_catalog.pg_class rel ON rel.oid = con.conrelid
INNER JOIN pg_catalog.pg_namespace nsp ON nsp.oid = connamespace
WHERE rel.relname = 'citus_local_partitioned_table';
conname
--------------------------------------------------
+ citus_local_partitioned_table_partition_col_excl
citus_local_partitioned_table_check
-(1 row)
+(2 rows)
```
Onur Tirtir
ThomasC02
Karina
manaldush
Cédric Villemain
Naisila Puka
German Eichberger
naisila
Mehmet YILMAZ
Muhammad Usama
Colm
OlgaSergeyevaB