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patroni.postgresql package

Subpackages

patroni.postgresql.available_parameters package
- Module contents
patroni.postgresql.mpp package
- Submodules
  - patroni.postgresql.mpp.citus module
    
    Citus
    
    CitusHandler
    
    PgDistNode
- Module contents

Submodules

Module contents

class _patroni.postgresql.Postgresql(_config: Dict[ str, Any], mpp: AbstractMPP) View on GitHub 

Bases: object +

POSTMASTER_START_TIME_ = 'pg_catalog.pg_postmaster_start_time()'_: +
TL_LSN_ = "CASE WHEN pg_catalog.pg_is_in_recovery() THEN 0 ELSE ('x' || pg_catalog.substr(pg_catalog.pg_{0}file_name(pg_catalog.pg_current_{0}_{1}()), 1, 8))::bit(32)::int END, CASE WHEN pg_catalog.pg_is_in_recovery() THEN 0 ELSE pg_catalog.pg_{0}_{1}_diff(pg_catalog.pg_current_{0}{2}_{1}(), '0/0')::bigint END, pg_catalog.pg_{0}_{1}_diff(pg_catalog.pg_last_{0}_replay_{1}(), '0/0')::bigint, pg_catalog.pg_{0}_{1}_diff(COALESCE(pg_catalog.pg_last_{0}_receive_{1}(), '0/0'), '0/0')::bigint, pg_catalog.pg_is_in_recovery() AND pg_catalog.pg_is_{0}_replay_paused()"_: +
__init\\__(config: Dict[ str, Any], mpp: AbstractMPP) → None View on GitHub : +
before_stop() → None View on GitHub : Synchronously run a script prior to stopping postgres. +
checkpoint_locations_from_controldata(_data: Dict[ str, str]) → Tuple[ int, int] | None View on GitHub : Get shutdown checkpoint location. +

Parameters

data – dict object with values returned by pg_controldata tool.

Returns

a tuple of checkpoint LSN for the cleanly shut down primary, and LSN of prev wal record (SWITCH) if we know that the checkpoint was written to the new WAL file due to the archive_mode=on. +
cluster_info_state_get(_name: str) → Any | None View on GitHub : +
do_before_stop(_cmd: str) → None View on GitHub : +
do_stop(_mode: str, block_callbacks: bool, checkpoint: bool, on_safepoint: Callable[[…], Any] | None, on_shutdown: Callable[[ int, int], Any] | None, before_shutdown: Callable[[…], Any] | None, stop_timeout: int | None) → Tuple[ bool, bool] View on GitHub : +
get_gucs() → CaseInsensitiveSet View on GitHub : Get all available GUCs based on postgres`+ ``--describe-config+` output. +

Returns

all available GUCs in the local Postgres server. +
pre_promote() → bool View on GitHub : Runs a fencing script after the leader lock is acquired but before the replica is promoted. If the script exits with a non-zero code, promotion does not happen and the leader key is removed from DCS. +
query(_sql: str, *params: Any) → List[ Tuple[ Any, …]] View on GitHub : Execute sql query with params and optionally return results. +

Parameters

Returns

a query response as a list of tuples if there is any.

Raises

Error if had issues while executing sql.
PostgresConnectionException: if had issues while connecting to the database.
RetryFailedError: if it was detected that connection/query failed due to PostgreSQL restart. +
version_file_exists() → bool View on GitHub : +
wait_for_connection_close(_postmaster: PostmasterProcess) → None View on GitHub : +
wait_promote(_wait_seconds: int) → bool | None View on GitHub : +
static \__wal_position(_is_primary: bool, wal_position: int, received_location: int | None, replayed_location: int | None) → int View on GitHub : +
property _available_gucs: CaseInsensitiveSet_: GUCs available in this Postgres server. +
call_nowait(cb_type: CallbackAction) → None View on GitHub : pick a callback command and call it without waiting for it to finish +
property _callback: Dict[ str, str]_: +
property _can_advance_slots: bool_: True if :attr:`major_version` is greater than 110000. +
can_create_replica_without_replication_connection(replica_methods: List[ str] | None) → bool View on GitHub : go through the replication methods to see if there are ones that does not require a working replication connection. +
property _cb_called: bool_: +
check_for_startup() → bool View on GitHub : Checks PostgreSQL status and returns if PostgreSQL is in the middle of startup. +
check_startup_state_changed() → bool View on GitHub : Checks if PostgreSQL has completed starting up or failed or still starting. + Should only be called when state == ‘starting’ +

Returns

True if state was changed from ‘starting’ +
checkpoint(connect_kwargs: Dict[ str, Any] | None = None, timeout: float | None = None) → str | None View on GitHub : +
property _cluster_info_query: str_: Returns the monitoring query with a fixed number of fields. + The query text is constructed based on current state in DCS and PostgreSQL version: +

function names depend on version. wal/lsn for v10+ and xlog/location for pre v10.

for primary we query timeline_id (extracted from pg_walfile_name()) and pg_current_wal_lsn()

for replicas we query pg_last_wal_receive_lsn(), pg_last_wal_replay_lsn(), and pg_is_wal_replay_paused()

for v9.6+ we query primary_slot_name and primary_conninfo from pg_stat_get_wal_receiver()

for v11+ with permanent logical slots we query from pg_replication_slots and aggregate the result

for standby_leader node running v9.6+ we also query pg_control_checkpoint to fetch timeline_id

if sync replication is enabled we query pg_stat_replication and aggregate the result. In addition to that we get current values of synchronous_commit and synchronous_standby_names GUCs.
If some conditions are not satisfied we simply put static values instead. E.g., NULL, 0, ‘’, and so on. +
configure_server_parameters() → None View on GitHub : +
connection() → connection3 | Connection3[Any] View on GitHub : +
controldata() → Dict[ str, str] View on GitHub : return the contents of pg_controldata, or non-True value if pg_controldata call failed +
property _create_replica_methods: List[ str]_: +
property _data_dir: str_: +
data_directory_empty() → bool View on GitHub : +
property _database: str_: +
property _enforce_hot_standby_feedback: bool_: +
ensure_major_version_is_known() → bool View on GitHub : Calls configure_server_parameters() if _major_version is not known +

Returns

True if _major_version is set, otherwise False +
follow(member: Leader | Member | None, role: str = 'replica', timeout: float | None = None, do_reload: bool = False) → bool | None View on GitHub : Reconfigure postgres to follow a new member or use different recovery parameters. + Method may call on_role_change callback if role is changing. +

Parameters

Returns

True - if restart/reload were successfully performed, False - if restart/reload failed None - if nothing was done or if Postgres is still in starting state after timeout seconds. +
get_guc_value(name: str) → str | None View on GitHub : +
get_history(timeline: int) → List[ Tuple[ int, int, str] | Tuple[ int, int, str, str, str]] View on GitHub : +
get_major_version() → int View on GitHub : Reads major version from PG_VERSION file +

Returns

major PostgreSQL version in integer format or 0 in case of missing file or errors +
get_postgres_role_from_data_directory() → str View on GitHub : +
get_primary_timeline() → int View on GitHub : Returns

current timeline if postgres is running as a primary or 0. +
get_replica_timeline() → int | None View on GitHub : +
get_replication_connection_cursor(host: str | None = None, port: int | str = 5432, **kwargs: Any) → Iterator[cursor | Cursor[Any]] View on GitHub : +
handle_parameter_change() → None View on GitHub : +
initdb(*args: str, **kwargs: Any) → bool View on GitHub : Builds and executes the initdb command. +

Parameters

Returns

True if the result of subprocess.call\',+ ``+the+ ``+exit+ ``+code,+ ``+is`+ ``\'\'0+`. +
is_healthy() → bool View on GitHub : +
is_primary() → bool View on GitHub : +
is_running() → PostmasterProcess | None View on GitHub : Returns PostmasterProcess if one is running on the data directory or None. If most recently seen process is running updates the cached process based on pid file. +
is_starting() → bool View on GitHub : +
last_operation() → int View on GitHub : +
latest_checkpoint_location() → int | None View on GitHub : Get shutdown checkpoint location. + Note

In case if checkpoint was written to the new WAL file due to the archive_mode=on we return LSN of the previous wal record (SWITCH). + Returns::: checkpoint LSN for the cleanly shut down primary. +
property _lsn_name: str_: +
property _major_version: int_: +
move_data_directory() → None View on GitHub : +
parse_wal_record(timeline: str, lsn: str) → Tuple[ str, str, str, str] | Tuple[ None, None, None, None] View on GitHub : +
property _pending_restart_reason: CaseInsensitiveDict_: Get _pending_restart_reason value.
_pending_restart_reason is a CaseInsensitiveDict object of the PG parameters that are causing pending restart state. Every key is a parameter name, value - a dictionary containing the old and the new value (see get_param_diff()). +
pg_control_exists() → bool View on GitHub : +
pg_control_timeline() → int | None View on GitHub : +
pg_ctl(cmd: str, *args: str, **kwargs: Any) → bool View on GitHub : Builds and executes pg_ctl command +

Returns

!True when return_code == 0, otherwise !False +
pg_isready() → str View on GitHub : Runs pg_isready to see if PostgreSQL is accepting connections. +

Returns

‘ok’ if PostgreSQL is up, ‘reject’ if starting up, ‘no_resopnse’ if not up. +
pg_stat_replication() → List[ Dict[ str, Any]] View on GitHub : Returns

a result set of ‘SELECT * FROM pg_stat_replication’. +
pg_tblspc_realpaths() → Dict[ str, str] View on GitHub : Returns a dict containing the symlink (key) and target (values) for the tablespaces +
pg_wal_realpath() → Dict[ str, str] View on GitHub : Returns a dict containing the symlink (key) and target (value) for the wal directory +
pgcommand(cmd: str) → str View on GitHub : Return path to the specified PostgreSQL command. + Note

If `+postgresql.bin_name.*cmd*+` was configured by the user then that binary name is used, otherwise the default binary name _cmd_ is used. + Parameters::: *cmd* – the Postgres binary name to get path to. Returns::: path to Postgres binary named _cmd_. +
postmaster_start_time() → str | None View on GitHub : +
primary_conninfo() → str | None View on GitHub : +
primary_slot_name() → str | None View on GitHub : +
promote(wait_seconds: int, task: CriticalTask, before_promote: Callable[[…], Any] | None = None) → bool | None View on GitHub : +
query(sql: str, *params: Any, retry: bool = True) → List[ Tuple[ Any, …]] View on GitHub : Execute sql query with params and optionally return results. +

Parameters

Returns

a query response as a list of tuples if there is any.

Raises

Error if had issues while executing sql.
PostgresConnectionException: if had issues while connecting to the database.
RetryFailedError: if it was detected that connection/query failed due to PostgreSQL restart or if retry deadline was exceeded. +
received_location() → int | None View on GitHub : +
received_timeline() → int | None View on GitHub : +
reload(block_callbacks: bool = False) → bool View on GitHub : +
reload_config(config: Dict[ str, Any], sighup: bool = False) → None View on GitHub : +
remove_data_directory() → None View on GitHub : +
replay_paused() → bool View on GitHub : +
replayed_location() → int | None View on GitHub : +
replica_cached_timeline(primary_timeline: int | None) → int | None View on GitHub : +
replica_method_can_work_without_replication_connection(method: str) → bool View on GitHub : +
replica_method_options(method: str) → Dict[ str, Any] View on GitHub : +
replication_state() → str | None View on GitHub : Checks replication state from pg_stat_get_wal_receiver(). + Note

Available only since 9.6 + Returns::: `+streaming+`, `+in+``+ +``+archive+``+ +``+recovery+`, or `+None+` +
replication_state_from_parameters(is_primary: bool, receiver_state: str | None, restore_command: str | None) → str | None View on GitHub : Figure out the replication state from input parameters. + Note

This method could be only called when Postgres is up, running and queries are successfuly executed. + Is_primary::: True is postgres is not running in recovery Receiver_state::: value from pg_stat_get_wal_receiver.state or None if Postgres is older than 9.6 Restore_command::: value of `+restore_command+` GUC for PostgreSQL 12+ or postgresql.recovery_conf.restore_command if it is set in Patroni configuration Returns::: +
reset_cluster_info_state(cluster: Cluster | None, tags: Tags | None = None) → None View on GitHub : Reset monitoring query cache. + Note

It happens in the beginning of heart-beat loop and on change of synchronous_standby_names. + Parameters::: +
restart(timeout: float | None = None, task: CriticalTask | None = None, block_callbacks: bool = False, role: str | None = None, before_shutdown: Callable[[…], Any] | None = None, after_start: Callable[[…], Any] | None = None) → bool | None View on GitHub : Restarts PostgreSQL. + When timeout parameter is set the call will block either until PostgreSQL has started, failed to start or timeout arrives. +

Returns

True when restart was successful and timeout did not expire when waiting. +
resume_wal_replay() → None View on GitHub : +
property _role: str_: +
schedule_sanity_checks_after_pause() → None View on GitHub : After coming out of pause we have to: 1. configure server parameters if necessary 2. sync replication slots, because it might happen that slots were removed 3. get new ‘Database system identifier’ to make sure that it wasn’t changed +
property _server_version: int_: +
set_enforce_hot_standby_feedback(value: bool) → None View on GitHub : +
set_pending_restart_reason(diff_dict: CaseInsensitiveDict) → None View on GitHub : Set new or update current _pending_restart_reason. +

Parameters

diff_dict – :class:`CaseInsensitiveDict` object with the parameters that are causing pending restart state with the diff of their values. Used to reset/update the _pending_restart_reason. +
set_role(value: str) → None View on GitHub : +
set_state(value: str) → None View on GitHub : +
slots() → Dict[ str, int] View on GitHub : +
start(timeout: float | None = None, task: CriticalTask | None = None, block_callbacks: bool = False, role: str | None = None, after_start: Callable[[…], Any] | None = None) → bool | None View on GitHub : Start PostgreSQL + Waits for postmaster to open ports or terminate so pg_isready can be used to check startup completion or failure. +

Returns

True if start was initiated and postmaster ports are open, False if start failed, and None if postgres is still starting up +
property _state: str_: +
stop(mode: str = 'fast', block_callbacks: bool = False, checkpoint: bool | None = None, on_safepoint: Callable[[…], Any] | None = None, on_shutdown: Callable[[ int, int], Any] | None = None, before_shutdown: Callable[[…], Any] | None = None, stop_timeout: int | None = None) → bool View on GitHub : Stop PostgreSQL + Supports a callback when a safepoint is reached. A safepoint is when no user backend can return a successful commit to users. Currently this means we wait for user backends to close. But in the future alternate mechanisms could be added. +

Parameters

+
property _supports_multiple_sync: bool_: True if Postgres version supports more than one synchronous node. +

Type

returns +
synchronous_commit() → str View on GitHub : Returns

“synchronous_commit” GUC value. +
synchronous_standby_names() → str View on GitHub : Returns

“synchronous_standby_names” GUC value. +
property _sysid: str_: +
terminate_postmaster(postmaster: PostmasterProcess, mode: str, stop_timeout: int | None) → bool | None View on GitHub : +
terminate_starting_postmaster(postmaster: PostmasterProcess) → None View on GitHub : Terminates a postmaster that has not yet opened ports or possibly even written a pid file. Blocks until the process goes away. +
time_in_state() → float View on GitHub : +
timeline_wal_position() → Tuple[ int, int, int | None] View on GitHub : +
wait_for_port_open(postmaster: PostmasterProcess, timeout: float) → bool View on GitHub : Waits until PostgreSQL opens ports. +
wait_for_startup(timeout: float = 0) → bool | None View on GitHub : Waits for PostgreSQL startup to complete or fail. +

Returns

True if start was successful, False otherwise +
property _wal_dir: str_: +
property _wal_flush: str_: For PostgreSQL 9.6 onwards we want to use pg_current_wal_flush_lsn()/pg_current_xlog_flush_location(). +
property _wal_name: str_: +
waldump(timeline: int | str, lsn: str, limit: int) → Tuple[ bytes | None, bytes | None] View on GitHub 

patroni.postgresql.null_context() View on GitHub 

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