Source code for airflow.providers.apache.hive.sensors.metastore_partition

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from __future__ import annotations

from typing import TYPE_CHECKING, Any, Sequence

from airflow.providers.common.sql.sensors.sql import SqlSensor

if TYPE_CHECKING:
    from airflow.utils.context import Context


[docs]class MetastorePartitionSensor(SqlSensor):
    """
    An alternative to the HivePartitionSensor that talk directly to the MySQL db.

    This was created as a result of observing sub optimal queries generated by the
    Metastore thrift service when hitting subpartitioned tables. The Thrift service's
    queries were written in a way that would not leverage the indexes.

    :param schema: the schema
    :param table: the table
    :param partition_name: the partition name, as defined in the PARTITIONS
        table of the Metastore. Order of the fields does matter.
        Examples: ``ds=2016-01-01`` or
        ``ds=2016-01-01/sub=foo`` for a sub partitioned table
    :param mysql_conn_id: a reference to the MySQL conn_id for the metastore
    """

[docs]    template_fields: Sequence[str] = ("partition_name", "table", "schema")
[docs]    ui_color = "#8da7be"

    def __init__(
        self,
        *,
        table: str,
        partition_name: str,
        schema: str = "default",
        mysql_conn_id: str = "metastore_mysql",
        **kwargs: Any,
    ):
        self.partition_name = partition_name
        self.table = table
        self.schema = schema
        self.first_poke = True
        self.conn_id = mysql_conn_id
        # TODO(aoen): We shouldn't be using SqlSensor here but MetastorePartitionSensor.
        # The problem is the way apply_defaults works isn't compatible with inheritance.
        # The inheritance model needs to be reworked in order to support overriding args/
        # kwargs with arguments here, then 'conn_id' and 'sql' can be passed into the
        # constructor below and apply_defaults will no longer throw an exception.
        super().__init__(**kwargs)

[docs]    def poke(self, context: Context) -> Any:
        if self.first_poke:
            self.first_poke = False
            if "." in self.table:
                self.schema, self.table = self.table.split(".")
            self.sql = f"""
            SELECT 'X'
            FROM PARTITIONS A0
            LEFT OUTER JOIN TBLS B0 ON A0.TBL_ID = B0.TBL_ID
            LEFT OUTER JOIN DBS C0 ON B0.DB_ID = C0.DB_ID
            WHERE
                B0.TBL_NAME = '{self.table}' AND
                C0.NAME = '{self.schema}' AND
                A0.PART_NAME = '{self.partition_name}';
            """
        return super().poke(context)