DESCRIPTION: This change starts a maintenance deamon at the time of
server start if there is a designated main database.
This is the code flow:
1. User designates a main database:
`ALTER SYSTEM SET citus.main_db = "myadmindb";`
2. When postmaster starts, in _PG_Init, citus calls
`InitializeMaintenanceDaemonForMainDb`
This function registers a background worker to run
`CitusMaintenanceDaemonMain `with `databaseOid = 0 `
3. `CitusMaintenanceDaemonMain ` takes some special actions when
databaseOid is 0:
- Gets the citus.main_db value.
- Connects to the citus.main_db
- Now the `MyDatabaseId `is available, creates a hash entry for it.
- Then follows the same control flow as for a regular db,
When debugging postgres it is quite hard to get to the source for
`errfinish` in `elog.c`. Instead of relying on the developer to set a
breakpoint in the `elog.c` file for `errfinish` for `elevel == ERROR`,
this change adds the breakpoint to `.gdbinit`. This makes sure that
whenever a debugger is attached to a postgres backend it will break on
postgres errors.
When attaching the debugger a small banner is printed that explains how
to disable the breakpoint.
HasDistributionKey & HasDistributionKeyCacheEntry returns true when the
corresponding table has a distribution key, the comments state the
opposite,
which should be fixed.
Signed-off-by: Zhao Junwang <zhjwpku@gmail.com>
Co-authored-by: Onur Tirtir <onurcantirtir@gmail.com>
There was a bug reported for previous versions of Citus where
shard\_size was returning NULL for tables with spaces in them. It works
fine on the main branch though, but I'm still adding a test for this to
the main branch because it seems a good test to have.
During the creation of the devcontainer we need to add a ppa repository,
which is easiest done via software-properies-common. As turns out this
installes pkexec into the container as a side effect.
When vscode tries to attach a debugger it first checks if pkexec is
installed as this gives a nicer popup asking for elevation of rights to
attach to the process. However, since dev containers don't have a
windowing system running pkexec isn't working as expected and thus
prevents the debugger from attaching.
Without pkexec in the container vscode 'falls back' to plain old sudo
which we can run passwordless in the container.
For pkexec to be removed we need to first purge
software-propertied-common as well as autoremove all packages that were
installed due to the installation of said package. By performing this
all in one step we minimize the size of the layer we are creating.
DESCRIPTION: Send keepalive messages during the logical replication
phase of large shard splits to avoid timeouts.
During the logical replication part of the shard split process, split
decoder filters out the wal records produced by the initial copy. If the
number of wal records is big, then split decoder ends up processing for
a long time before sending out any wal records through pgoutput. Hence
the wal receiver may time out and restarts repeatedly causing our split
driver code catch up logic to fail.
Notes:
1. If the wal_receiver_timeout is set to a very small number e.g. 600ms,
it may time out before receiving the keepalives. My tests show that this
code works best when the` wal_receiver_timeout `is set to 1minute, which
is the default value.
2. Once a logical replication worker time outs, a new one gets launched.
The new logical replication worker sets the pg_stat_subscription columns
to initial values. E.g. the latest_end_lsn is set to 0. Our driver logic
in `WaitForGroupedLogicalRepTargetsToCatchUp` can not handle LSN value
to go back. This is the main reason for it to get stuck in the infinite
loop.
This change adds a devcontainer configuration to the Citus project. This
devcontainer allows for quick generation of isolated development
environments, either local on the machine of a developer or in a cloud,
like github codepaces.
The devcontainer is updated automatically by github actions when its
configuration changes.
For more detailed instructions on how to quickstart the development in a
container see CONTRIBUTING.md
DESCRIPTION: Fix leaking of memory and memory contexts in Foreign
Constraint Graphs
Previously, every time we (re)created the Foreign Constraint
Relationship Graph, we created a new Memory Context while loosing a
reference to the previous context. This old context could still have
left over memory in there causing a memory leak.
With this patch we statically have one memory context that we lazily
initialize the first time we create our foreign constraint relationship
graph. On every subsequent creation, beside destroying our previous
hashmap we also reset our memory context to remove any left over
references.
This commit aims to add a comprehensive guide that covers all essential
aspects of Citus, including planning, execution, locking mechanisms,
shard moves, 2PC, and many other major components of Citus.
Co-authored-by: Marco Slot <marco.slot@gmail.com>
When testing rolling Citus upgrades, coordinator should not be upgraded
until we upgrade all the workers.
---------
Co-authored-by: Jelte Fennema-Nio <github-tech@jeltef.nl>
DESCRIPTION: Shard moves/isolate report LSN's in lsn format
While investigating an issue with our catchup mechanism on certain
postgres versions we noticed we print LSN's in the format of the native
long type. This is an uncommon representation for LSN's in postgres
logs.
This patch changes the output of our log message to go from the long
type representation to the native LSN type representation. Making it
easier for postgres users to recognize and compare LSN's with other
related reports.
example of new output:
```
2023-09-25 17:28:47.544 CEST [11345] LOG: The LSN of the target subscriptions on node localhost:9701 have increased from 0/0 to 0/E1ED20F8 at 2023-09-25 17:28:47.544165+02 where the source LSN is 1/415DCAD0
```
If you make a fresh install make clean is not
required. However, if you install before, without
a make install, one can get errors
---------
Co-authored-by: aykut-bozkurt <51649454+aykut-bozkurt@users.noreply.github.com>
When cdc got added the makefiles hardcoded the `.so` extension instead
of using the platform specifc `$(DLSUFFIX)` variable used by `pgxs.mk`.
Also don't remove installed cdc artifacts on `make clean`.
This was sometimes failing when running locally due to some local shard
still existing due to. This fixes that. We normally silence all
`drop schema cascade` output like this anyway to avoid unnecessary
diffs when modifying a test later on.
centos 7 and oracle 7 is not being supported for newer releases by
Postgres. Therefore, getting package download errors in packaging
pipelines.
This PR removes el/7 and ol/7 Postgres 16 pipelines
DESCRIPTION: Adds support for ALTER DATABASE <db_name> SET .. statement
propagation
SET statements in Postgres has a common structure which is already being
used in Alter Function
statement.
In this PR, I added a util file; citus_setutils and made it usable for
both for
alter database<db_name>set .. and alter function ... set ... statements.
With this PR, below statements will be propagated
```sql
ALTER DATABASE name SET configuration_parameter { TO | = } { value | DEFAULT }
ALTER DATABASE name SET configuration_parameter FROM CURRENT
ALTER DATABASE name RESET configuration_parameter
ALTER DATABASE name RESET ALL
```
Additionally, there was a bug in processing float values in the common
code block.
I fixed this one as well
Previous
```C
case T_Float:
{
appendStringInfo(buf, " %s", strVal(value));
break;
}
```
Now
```C
case T_Float:
{
appendStringInfo(buf, " %s", nodeToString(value));
break;
}
```
DESCRIPTION: Adds ALTER DATABASE WITH ... and REFRESH COLLATION VERSION
support
This PR adds supports for basic ALTER DATABASE statements propagation
support. Below statements are supported:
ALTER DATABASE <database_name> with IS_TEMPLATE <true/false>;
ALTER DATABASE <database_name> with CONNECTION LIMIT <integer_value>;
ALTER DATABASE <database_name> REFRESH COLLATION VERSION;
---------
Co-authored-by: Jelte Fennema-Nio <jelte.fennema@microsoft.com>
We currently don't support propagating these options in Citus
Relevant PG commits:
https://github.com/postgres/postgres/commit/e3ce2dehttps://github.com/postgres/postgres/commit/3d14e17
Limitation:
We also need to take care of generated GRANT statements by dependencies
in attempt to distribute something else. Specifically, this part of the
code in `GenerateGrantRoleStmtsOfRole`:
```
grantRoleStmt->admin_opt = membership->admin_option;
```
In PG16, membership also has `inherit_option` and `set_option` which
need to properly be part of the `grantRoleStmt`. We can skip for now
since #7164 will take care of this soon, and also this is not an
expected use-case.
Add citus_schema_move() that can be used to move tenant tables within a distributed
schema to another node. The function has two variations as simple wrappers around
citus_move_shard_placement() and citus_move_shard_placement_with_nodeid() respectively.
They pick a shard that belongs to the given tenant schema and resolve the source node
that contain the shards under given tenant schema. Hence their signatures are quite
similar to underlying functions:
```sql
-- citus_schema_move(), using target node name and node port
CREATE OR REPLACE FUNCTION pg_catalog.citus_schema_move(
schema_id regnamespace,
target_node_name text,
target_node_port integer,
shard_transfer_mode citus.shard_transfer_mode default 'auto')
RETURNS void
LANGUAGE C STRICT
AS 'MODULE_PATHNAME', $$citus_schema_move$$;
-- citus_schema_move(), using target node id
CREATE OR REPLACE FUNCTION pg_catalog.citus_schema_move(
schema_id regnamespace,
target_node_id integer,
shard_transfer_mode citus.shard_transfer_mode default 'auto')
RETURNS void
LANGUAGE C STRICT
AS 'MODULE_PATHNAME', $$citus_schema_move_with_nodeid$$;
```
Since in PG16, truncate triggers are supported on foreign tables, we add
the citus_truncate_trigger to Citus foreign tables as well, such that the TRUNCATE
command is propagated to the table's single local shard as well.
Note that TRUNCATE command was working for foreign tables even before this
commit: see https://github.com/citusdata/citus/pull/7170#issuecomment-1706240593 for details
This commit also adds tests with user-enabled truncate triggers on Citus foreign tables:
both trigger on the shell table and on its single foreign local shard.
Relevant PG commit:
https://github.com/postgres/postgres/commit/3b00a94
**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>
Emel Şimşek
Nils Dijk
Benjamin O
Gokhan Gulbiz
Naisila Puka
zhjwpku
Onur Tirtir
Gürkan İndibay
Jelte Fennema-Nio
Önder Kalacı
dependabot[bot]
Hanefi Onaldi
Teresa Giacomini
aykut-bozkurt