DESCRIPTION: Adds support for distributed `CREATE/DROP DATABASE `
commands from the databases where Citus is not installed
---------
Co-authored-by: Onur Tirtir <onurcantirtir@gmail.com>
DESCRIPTION: Adds support for distributed `GRANT .. ON DATABASE TO USER`
commands from the databases where Citus is not installed
---------
Co-authored-by: Onur Tirtir <onurcantirtir@gmail.com>
DESCRIPTION: Adds support for distributed role-membership management
commands from the databases where Citus is not installed (`GRANT <role>
TO <role>`)
This PR also refactors the code-path that allows executing some of the
node-wide commands so that we use send deparsed query string to other
nodes instead of the `queryString` passed into utility hook.
---------
Co-authored-by: Onur Tirtir <onurcantirtir@gmail.com>
This PR makes the connections to other nodes for
`mark_object_distributed` use the same user as
`execute_command_on_remote_nodes_as_user` so they'll use the same
connection.
DESCRIPTION: Adds support for issuing `CREATE`/`DROP` DATABASE commands
from worker nodes
With this commit, we allow issuing CREATE / DROP DATABASE commands from
worker nodes too.
As in #7278, this is not allowed when the coordinator is not added to
metadata because we don't ever sync metadata changes to coordinator
when adding coordinator to the metadata via
`SELECT citus_set_coordinator_host('<hostname>')`, or equivalently, via
`SELECT citus_add_node(<coordinator_node_name>, <coordinator_node_port>, 0)`.
We serialize database management commands by acquiring a Citus specific
advisory lock on the first primary worker node if there are any workers in the
cluster. As opposed to what we've done in https://github.com/citusdata/citus/pull/7278
for role management commands, we try to avoid from running into distributed deadlocks
as much as possible. This is because, while distributed deadlocks that can happen around
role management commands can be detected by Citus, this is not the case for database
management commands because most of them cannot be run inside in a transaction block.
In that case, Citus cannot even detect the distributed deadlock because the command is not
part of a distributed transaction at all, then the command execution might not return the
control back to the user for an indefinite amount of time.
DESCRIPTION: Adds support for 2PC from non-Citus main databases
This PR only adds support for `CREATE USER` queries, other queries need
to be added. But it should be simple because this PR creates the
underlying structure.
Citus main database is the database where the Citus extension is
created. A non-main database is all the other databases that are in the
same node with a Citus main database.
When a `CREATE USER` query is run on a non-main database we:
1. Run `start_management_transaction` on the main database. This
function saves the outer transaction's xid (the non-main database
query's transaction id) and marks the current query as main db command.
2. Run `execute_command_on_remote_nodes_as_user("CREATE USER
<username>", <username to run the command>)` on the main database. This
function creates the users in the rest of the cluster by running the
query on the other nodes. The user on the current node is created by the
query on the outer, non-main db, query to make sure consequent commands
in the same transaction can see this user.
3. Run `mark_object_distributed` on the main database. This function
adds the user to `pg_dist_object` in all of the nodes, including the
current one.
This PR also implements transaction recovery for the queries from
non-main databases.
This change adds a script to programatically group all includes in a
specific order. The script was used as a one time invocation to group
and sort all includes throught our formatted code. The grouping is as
follows:
- System includes (eg. `#include<...>`)
- Postgres.h (eg. `#include "postgres.h"`)
- Toplevel imports from postgres, not contained in a directory (eg.
`#include "miscadmin.h"`)
- General postgres includes (eg . `#include "nodes/..."`)
- Toplevel citus includes, not contained in a directory (eg. `#include
"citus_verion.h"`)
- Columnar includes (eg. `#include "columnar/..."`)
- Distributed includes (eg. `#include "distributed/..."`)
Because it is quite hard to understand the difference between toplevel
citus includes and toplevel postgres includes it hardcodes the list of
toplevel citus includes. In the same manner it assumes anything not
prefixed with `columnar/` or `distributed/` as a postgres include.
The sorting/grouping is enforced by CI. Since we do so with our own
script there are not changes required in our uncrustify configuration.
DESCRIPTION: Adds support for propagating `CREATE`/`DROP` database
In this PR, create and drop database support is added.
For CREATE DATABASE:
* "oid" option is not supported
* specifying "strategy" to be different than "wal_log" is not supported
* specifying "template" to be different than "template1" is not
supported
The last two are because those are not saved in `pg_database` and when
activating a node, we cannot assume what parameters were provided when
creating the database.
And "oid" is not supported because whether user specified an arbitrary
oid when creating the database is not saved in pg_database and we want
to avoid from oid collisions that might arise from attempting to use an
auto-assigned oid on workers.
Finally, in case of node activation, GRANTs for the database are also
propagated.
---------
Co-authored-by: Jelte Fennema-Nio <github-tech@jeltef.nl>
Co-authored-by: Jelte Fennema-Nio <jelte.fennema@microsoft.com>
Co-authored-by: Onur Tirtir <onurcantirtir@gmail.com>
DESCRIPTION: Adds support from issuing role management commands from worker nodes
It's unlikely to get into a distributed deadlock with role commands, we
don't care much about them at the moment.
There were several attempts to reduce the chances of a deadlock but we
didn't any of them merged into main branch yet, see:
#7325#7016#7009
**Problem:**
Previously we always used an outside superuser connection to overcome
permission issues for the current user while propagating dependencies.
That has mainly 2 problems:
1. Visibility issues during dependency propagation, (metadata connection
propagates some objects like a schema, and outside transaction does not
see it and tries to create it again)
2. Security issues (it is preferrable to use current user's connection
instead of extension superuser)
**Solution (high level):**
Now, we try to make a smarter decision on whether should we use an
outside superuser connection or current user's metadata connection. We
prefer using current user's connection if any of the objects, which is
already propagated in the current transaction, is a dependency for a
target object. We do that since we assume if current user has
permissions to create the dependency, then it can most probably
propagate the target as well.
Our assumption is expected to hold most of the times but it can still be
wrong. In those cases, transaction would fail and user should set the
GUC `citus.create_object_propagation` to `deferred` to work around it.
**Solution:**
1. We track all objects propagated in the current transaction (we can
handle subtransactions),
2. We propagate dependencies via the current user's metadata connection
if any dependency is created in the current transaction to address
issues listed above. Otherwise, we still use an outside superuser
connection.
DESCRIPTION: Fixes some object propagation errors seen with transaction
blocks.
Fixes https://github.com/citusdata/citus/issues/6614
---------
Co-authored-by: Nils Dijk <nils@citusdata.com>
For a database that does not create the citus extension by running
` CREATE EXTENSION citus;`
`CitusHasBeenLoaded ` function ends up querying the `pg_extension` table
every time it is invoked. This is not an ideal situation for a such a
database.
The idea in this PR is as follows:
### A new field in MetadataCache.
Add a new variable `extensionCreatedState `of the following type:
```
typedef enum ExtensionCreatedState
{
UNKNOWN = 0,
CREATED = 1,
NOTCREATED = 2,
} ExtensionCreatedState;
```
When the MetadataCache is invalidated, `ExtensionCreatedState` will be
set to UNKNOWN.
### Invalidate MetadataCache when CREATE/DROP/ALTER EXTENSION citus
commands are run.
- Register a callback function, named
`InvalidateDistRelationCacheCallback`, for relcache invalidation during
the shared library initialization for `citus.so`. This callback function
is invoked in all the backends whenever the relcache is invalidated in
one of the backends. (This could be caused many DDLs operations).
- In the cache invalidation callback,`
InvalidateDistRelationCacheCallback`, invalidate `MetadataCache` zeroing
it out.
- In `CitusHasBeenLoaded`, perform the costly citus is loaded check only
if the `MetadataCache` is not valid.
### Downsides
Any relcache invalidation (caused by various DDL operations) will case
Citus MetadataCache to get invalidated. Most of the time it will be
unnecessary. But we rely on that DDL operations on relations will not be
too frequent.
This commit is the second and last phase of dropping PG13 support.
It consists of the following:
- Removes all PG_VERSION_13 & PG_VERSION_14 from codepaths
- Removes pg_version_compat entries and columnar_version_compat entries
specific for PG13
- Removes alternative pg13 test outputs
- Removes PG13 normalize lines and fix the test outputs based on that
It is a continuation of 5bf163a27d
gurkanindibay
Halil Ozan Akgül
eaydingol
Onur Tirtir
Nils Dijk
aykut-bozkurt
Emel Şimşek
Naisila Puka