With this PR, we allow creating distributed tables with without
specifying a shard key via create_distributed_table(). Here are the
the important details about those tables:
* Specifying `shard_count` is not allowed because it is assumed to be 1.
* We mostly call such tables as "null shard-key" table in code /
comments.
* To avoid doing a breaking layout change in create_distributed_table();
instead of throwing an error, it will inform the user that
`distribution_type`
param is ignored unless it's explicitly set to NULL or 'h'.
* `colocate_with` param allows colocating such null shard-key tables to
each other.
* We define this table type, i.e., NULL_SHARD_KEY_TABLE, as a subclass
of
DISTRIBUTED_TABLE because we mostly want to treat them as distributed
tables in terms of SQL / DDL / operation support.
* Metadata for such tables look like:
- distribution method => DISTRIBUTE_BY_NONE
- replication model => REPLICATION_MODEL_STREAMING
- colocation id => **!=** INVALID_COLOCATION_ID (distinguishes from
Citus local tables)
* We assign colocation groups for such tables to different nodes in a
round-robin fashion based on the modulo of "colocation id".
Note that this PR doesn't care about DDL (except CREATE TABLE) / SQL /
operation (i.e., Citus UDFs) support for such tables but adds a
preliminary
API.
Now that we will soon add another table type having DISTRIBUTE_BY_NONE
as distribution method and that we want the code to interpret such
tables mostly as distributed tables, let's make the definition of those
other two table types more strict by removing
CITUS_TABLE_WITH_NO_DIST_KEY
macro.
And instead, use HasDistributionKey() check in the places where the
logic applies to all table types that have / don't have a distribution
key. In future PRs, we might want to convert some of those
HasDistributionKey() checks if logic only applies to Citus local /
reference tables, not the others.
And adding HasDistributionKey() also allows us to consider having
DISTRIBUTE_BY_NONE as the distribution method as a "table attribute"
that can apply to distributed tables too, rather something that
determines the table type.
DESCRIPTION: Fix foreign key validation skip at the end of shard move
In eadc88a we started completely skipping foreign key constraint
validation at the end of a non blocking shard move, instead of only for
foreign keys to reference tables. However, it turns out that this didn't
work at all because of a hard to notice bug: By resetting the
SkipConstraintValidation flag at the end of our utility hook, we
actually make the SET command that sets it a no-op.
This fixes that bug by removing the code that resets it. This is fine
because #6543 removed the only place where we set the flag in C code. So
the resetting of the flag has no purpose anymore. This PR also adds a
regression test, because it turned out we didn't have any otherwise we
would have caught that the feature was completely broken.
It also moves the constraint validation skipping to the utility hook.
The reason is that #6550 showed us that this is the better place to skip
it, because it will also skip the planning phase and not just the
execution.
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.
Previously we would create foreign keys to reference table in an extra
fast way at the end of a shard move. This uses that same logic to also
do it for foreign keys between distributed tables.
Fixes#6141
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.
Added create_distributed_table_concurrently which is nonblocking variant of create_distributed_table.
It bases on the split API which takes advantage of logical replication to support nonblocking split operations.
Co-authored-by: Marco Slot <marco.slot@gmail.com>
Co-authored-by: aykutbozkurt <aykut.bozkurt1995@gmail.com>
With the previous version of this check we would disallow distributed
tables that did not have a colocationid, to have a foreign key to a
reference table. This fixes that, since there's no reason to disallow
that.
This commit brings following features:
Foreign key support from citus local tables to reference tables
* Foreign key support from reference tables to citus local tables
(only with RESTRICT & NO ACTION behavior)
* ALTER TABLE ENABLE/DISABLE trigger command support
* CREATE/DROP/ALTER trigger command support
and disallows:
* ALTER TABLE ATTACH/DETACH PARTITION commands
* CREATE TABLE <postgres table> ATTACH PARTITION <citus local table>
commands
* Foreign keys from postgres tables to citus local tables
(the other way was already disallowed)
for citus local tables.
Introduce table entry utility functions
Citus table cache entry utilities are introduced so that we can easily
extend existing functionality with minimum changes, specifically changes
to these functions. For example IsNonDistributedTableCacheEntry can be
extended for citus local tables without the need to scan the whole
codebase and update each relevant part.
* Introduce utility functions to find the type of tables
A table type can be a reference table, a hash/range/append distributed
table. Utility methods are created so that we don't have to worry about
how a table is considered as a reference table etc. This also makes it
easy to extend the table types.
* Add IsCitusTableType utilities
* Rename IsCacheEntryCitusTableType -> IsCitusTableTypeCacheEntry
* Change citus table types in some checks
With PG13 heap_* (heap_open, heap_close etc) are replaced with table_*
(table_open, table_close etc).
It is better to use the new table access methods in the codebase and
define the macros for the previous versions as we can easily remove the
macro without having to change the codebase when we drop the support for
the old version.
Commits that introduced this change on Postgres:
f25968c49697db673f6cd2a07b3f7626779f1827
e0c4ec07284db817e1f8d9adfb3fffc952252db0
4b21acf522d751ba5b6679df391d5121b6c4a35f
Command to see relevant commits on Postgres side:
git log --all --grep="heap_open"
To reduce code duplication, implement function that pushes search_path
to be NIL and sets addCatalog to true so that all objects outside of
pg_catalog will be schema-prefixed.
Do not release AccessShareLock when closing pg_constraint to prevent
modifications to be done on pg_constraint to make sure that caller
will process valid foreign key constraints through the transaction.
Onur Tirtir
Jelte Fennema
Philip Dubé
Jelte Fennema
Ahmet Gedemenli
Marco Slot
Halil Ozan Akgul
Hanefi Onaldi
SaitTalhaNisanci
Marco Slot
Philip Dubé