patroni.postgresql.mpp package
Submodules
- patroni.postgresql.mpp.citus module
Citus
CitusHandler
CitusHandler.__init__()
CitusHandler._abc_impl
CitusHandler._add_task()
CitusHandler.add_task()
CitusHandler.adjust_postgres_gucs()
CitusHandler.bootstrap()
CitusHandler.find_task_by_group()
CitusHandler.handle_event()
CitusHandler.ignore_replication_slot()
CitusHandler.load_pg_dist_node()
CitusHandler.on_demote()
CitusHandler.pick_task()
CitusHandler.process_task()
CitusHandler.process_tasks()
CitusHandler.query()
CitusHandler.run()
CitusHandler.schedule_cache_rebuild()
CitusHandler.sync_meta_data()
CitusHandler.update_node()
PgDistNode
Module contents
Abstract classes for MPP handler.
MPP stands for Massively Parallel Processing, and Citus belongs to this architecture. Currently, Citus is the only supported MPP cluster. However, we may consider adapting other databases such as TimescaleDB, GPDB, etc. into Patroni.
- class patroni.postgresql.mpp.AbstractMPP(config: Dict[str, str | int])View on GitHub
Bases:
ABC
An abstract class which should be passed to
AbstractDCS
.Note
We create
AbstractMPP
andAbstractMPPHandler
to solve the chicken-egg initialization problem. When initializing DCS, we dynamically create an object implementingAbstractMPP
, later this object is used to instantiate an object implementingAbstractMPPHandler
.- __init__(config: Dict[str, str | int]) None View on GitHub
Init method for
AbstractMPP
.- Parameters:
config – configuration of MPP section.
- _abc_impl = <_abc._abc_data object>
- _get_handler_cls() Iterator[Type[AbstractMPPHandler]] View on GitHub
Find Handler classes inherited from a class type of this object.
- Yields:
handler classes for this object.
- get_handler_impl(postgresql: Postgresql) AbstractMPPHandler View on GitHub
Find and instantiate Handler implementation of this object.
- Parameters:
postgresql – a reference to
Postgresql
object.- Raises:
PatroniException
: if the Handler class haven’t been found.- Returns:
an instantiated class that implements Handler for this object.
- is_coordinator() bool View on GitHub
Check whether this node is running in the coordinator PostgreSQL cluster.
- Returns:
True
if MPP is enabled and the group id of this node matches with thecoordinator_group_id
, otherwiseFalse
.
- is_enabled() bool View on GitHub
Check if MPP is enabled for a given MPP.
Note
We just check that the
_config
object isn’t empty and expect it to be empty only in case ofNull
.- Returns:
True
if MPP is enabled, otherwiseFalse
.
- is_worker() bool View on GitHub
Check whether this node is running as a MPP worker PostgreSQL cluster.
- Returns:
True
if MPP is enabled and this node is known to be not running as the coordinator PostgreSQL cluster, otherwiseFalse
.
- property k8s_group_label
Group label used for kubernetes DCS of the MPP cluster.
- Returns:
A string representation of the k8s group label of a given MPP implementation.
- property type: str
The type of the MPP cluster.
- Returns:
A string representation of the type of a given MPP implementation.
- abstract static validate_config(config: Any) bool View on GitHub
Check whether provided config is good for a given MPP.
- Parameters:
config – configuration of MPP section.
- Returns:
True
is config passes validation, otherwiseFalse
.
- class patroni.postgresql.mpp.AbstractMPPHandler(postgresql: Postgresql, config: Dict[str, str | int])View on GitHub
Bases:
AbstractMPP
An abstract class which defines interfaces that should be implemented by real handlers.
- __init__(postgresql: Postgresql, config: Dict[str, str | int]) None View on GitHub
Init method for
AbstractMPPHandler
.- Parameters:
postgresql – a reference to
Postgresql
object.config – configuration of MPP section.
- _abc_impl = <_abc._abc_data object>
- abstract adjust_postgres_gucs(parameters: Dict[str, Any]) None View on GitHub
Adjust GUCs in the current PostgreSQL configuration.
- Parameters:
parameters – dictionary of GUCs, with key as GUC name and the corresponding value as current GUC value.
- abstract bootstrap() None View on GitHub
Bootstrap handler.
Is called when the new cluster is initialized (through
initdb
or a custom bootstrap method).
- abstract handle_event(cluster: Cluster, event: Dict[str, Any]) None View on GitHub
Handle an event sent from a worker node.
- Parameters:
cluster – the currently known cluster state from DCS.
event – the event to be handled.
- abstract ignore_replication_slot(slot: Dict[str, str]) bool View on GitHub
Check whether provided replication slot existing in the database should not be removed.
Note
MPP database may create replication slots for its own use, for example to migrate data between workers using logical replication, and we don’t want to suddenly drop them.
- Parameters:
slot – dictionary containing the replication slot settings, like
name
,database
,type
, andplugin
.- Returns:
True
if the replication slots should not be removed, otherwiseFalse
.
- abstract on_demote() None View on GitHub
On demote handler.
Is called when the primary was demoted.
- abstract schedule_cache_rebuild() None View on GitHub
Cache rebuild handler.
Is called to notify handler that it has to refresh its metadata cache from the database.
- abstract sync_meta_data(cluster: Cluster) None View on GitHub
Sync meta data on the coordinator.
- Parameters:
cluster – the currently known cluster state from DCS.
- class patroni.postgresql.mpp.NullView on GitHub
Bases:
AbstractMPP
Dummy implementation of
AbstractMPP
.- __init__() None View on GitHub
Init method for
Null
.
- _abc_impl = <_abc._abc_data object>
- property coordinator_group_id: None
The group id of the coordinator PostgreSQL cluster.
- Returns:
always
None
.
- static validate_config(config: Any) bool View on GitHub
Check whether provided config is good for
Null
.- Returns:
always
True
.
- class patroni.postgresql.mpp.NullHandler(postgresql: Postgresql, config: Dict[str, str | int])View on GitHub
Bases:
Null
,AbstractMPPHandler
Dummy implementation of
AbstractMPPHandler
.- __init__(postgresql: Postgresql, config: Dict[str, str | int]) None View on GitHub
Init method for
NullHandler
.- Parameters:
postgresql – a reference to
Postgresql
object.config – configuration of MPP section.
- _abc_impl = <_abc._abc_data object>
- adjust_postgres_gucs(parameters: Dict[str, Any]) None View on GitHub
Adjust GUCs in the current PostgreSQL configuration.
- Parameters:
parameters – dictionary of GUCs, with key as GUC name and corresponding value as current GUC value.
- bootstrap() None View on GitHub
Bootstrap handler.
Is called when the new cluster is initialized (through
initdb
or a custom bootstrap method).
- handle_event(cluster: Cluster, event: Dict[str, Any]) None View on GitHub
Handle an event sent from a worker node.
- Parameters:
cluster – the currently known cluster state from DCS.
event – the event to be handled.
- ignore_replication_slot(slot: Dict[str, str]) bool View on GitHub
Check whether provided replication slot existing in the database should not be removed.
Note
MPP database may create replication slots for its own use, for example to migrate data between workers using logical replication, and we don’t want to suddenly drop them.
- Parameters:
slot – dictionary containing the replication slot settings, like
name
,database
,type
, andplugin
.- Returns:
always
False
.
- on_demote() None View on GitHub
On demote handler.
Is called when the primary was demoted.
- schedule_cache_rebuild() None View on GitHub
Cache rebuild handler.
Is called to notify handler that it has to refresh its metadata cache from the database.
- sync_meta_data(cluster: Cluster) None View on GitHub
Sync meta data on the coordinator.
- Parameters:
cluster – the currently known cluster state from DCS.
- patroni.postgresql.mpp.get_mpp(config: Config | Dict[str, Any]) AbstractMPP View on GitHub
Attempt to load and instantiate a MPP module from known available implementations.
- Parameters:
config – object or dictionary with Patroni configuration.
- Returns:
The successfully loaded MPP or fallback to
Null
.
- patroni.postgresql.mpp.iter_mpp_classes(config: Config | Dict[str, Any] | None = None) Iterator[Tuple[str, Type[AbstractMPP]]] View on GitHub
Attempt to import MPP modules that are present in the given configuration.
- Parameters:
config – configuration information with possible MPP names as keys. If given, only attempt to import MPP modules defined in the configuration. Else, if
None
, attempt to import any supported MPP module.- Yields:
tuples, each containing the module
name
and the imported MPP class object.