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from typing import Any, ClassVar, Dict, List, Type
from urllib.parse import unquote
import attrs
from data_diff.abcs.database_types import (
ColType,
DbPath,
JSON,
Timestamp,
TimestampTZ,
Float,
Decimal,
Integer,
TemporalType,
Native_UUID,
Text,
FractionalType,
Boolean,
Date,
Time,
)
from data_diff.databases.base import BaseDialect, ThreadedDatabase, import_helper, ConnectError
from data_diff.databases.base import (
MD5_HEXDIGITS,
CHECKSUM_HEXDIGITS,
_CHECKSUM_BITSIZE,
TIMESTAMP_PRECISION_POS,
CHECKSUM_OFFSET,
)
SESSION_TIME_ZONE = None # Changed by the tests
@import_helper("postgresql")
def import_postgresql():
import psycopg2.extras
psycopg2.extensions.set_wait_callback(psycopg2.extras.wait_select)
return psycopg2
@attrs.define(frozen=False)
class PostgresqlDialect(BaseDialect):
name = "PostgreSQL"
ROUNDS_ON_PREC_LOSS = True
SUPPORTS_PRIMARY_KEY: ClassVar[bool] = True
SUPPORTS_INDEXES = True
# https://www.postgresql.org/docs/current/datatype-numeric.html#DATATYPE-NUMERIC-DECIMAL
# without any precision or scale creates an “unconstrained numeric” column
# in which numeric values of any length can be stored, up to the implementation limits.
# https://www.postgresql.org/docs/current/datatype-numeric.html#DATATYPE-NUMERIC-TABLE
DEFAULT_NUMERIC_PRECISION = 16383
TYPE_CLASSES: ClassVar[Dict[str, Type[ColType]]] = {
# Timestamps
"timestamp with time zone": TimestampTZ,
"timestamp without time zone": Timestamp,
"timestamp": Timestamp,
"date": Date,
"time with time zone": Time,
"time without time zone": Time,
# Numbers
"double precision": Float,
"real": Float,
"decimal": Decimal,
"smallint": Integer,
"integer": Integer,
"numeric": Decimal,
"bigint": Integer,
# Text
"character": Text,
"character varying": Text,
"varchar": Text,
"text": Text,
"json": JSON,
"jsonb": JSON,
"uuid": Native_UUID,
"boolean": Boolean,
}
def quote(self, s: str):
return f'"{s}"'
def to_string(self, s: str):
return f"{s}::varchar"
def concat(self, items: List[str]) -> str:
joined_exprs = " || ".join(items)
return f"({joined_exprs})"
def _convert_db_precision_to_digits(self, p: int) -> int:
# Subtracting 2 due to wierd precision issues in PostgreSQL
return super()._convert_db_precision_to_digits(p) - 2
def set_timezone_to_utc(self) -> str:
return "SET TIME ZONE 'UTC'"
def current_timestamp(self) -> str:
return "current_timestamp"
def type_repr(self, t) -> str:
if isinstance(t, TimestampTZ):
return f"timestamp ({t.precision}) with time zone"
return super().type_repr(t)
def md5_as_int(self, s: str) -> str:
return f"('x' || substring(md5({s}), {1+MD5_HEXDIGITS-CHECKSUM_HEXDIGITS}))::bit({_CHECKSUM_BITSIZE})::bigint - {CHECKSUM_OFFSET}"
def md5_as_hex(self, s: str) -> str:
return f"md5({s})"
def normalize_timestamp(self, value: str, coltype: TemporalType) -> str:
def _add_padding(coltype: TemporalType, timestamp6: str):
return f"RPAD(LEFT({timestamp6}, {TIMESTAMP_PRECISION_POS+coltype.precision}), {TIMESTAMP_PRECISION_POS+6}, '0')"
try:
is_date = coltype.is_date
is_time = coltype.is_time
except:
is_date = False
is_time = False
if isinstance(coltype, Date) or is_date:
return f"cast({value} as varchar)"
if isinstance(coltype, Time) or is_time:
seconds = f"EXTRACT( epoch from {value})"
rounded = f"ROUND({seconds}, {coltype.precision})"
time_value = f"CAST('00:00:00' as time) + make_interval(0, 0, 0, 0, 0, 0, {rounded})" # 6th arg = seconds
converted = f"to_char({time_value}, 'hh24:mi:ss.ff6')"
return converted
if coltype.rounds:
# NULL value expected to return NULL after normalization
null_case_begin = f"CASE WHEN {value} IS NULL THEN NULL ELSE "
null_case_end = "END"
# 294277 or 4714 BC would be out of range, make sure we can't round to that
# TODO test timezones for overflow?
max_timestamp = "294276-12-31 23:59:59.0000"
min_timestamp = "4713-01-01 00:00:00.00 BC"
timestamp = f"least('{max_timestamp}'::timestamp(6), {value}::timestamp(6))"
timestamp = f"greatest('{min_timestamp}'::timestamp(6), {timestamp})"
interval = format((0.5 * (10 ** (-coltype.precision))), f".{coltype.precision+1}f")
rounded_timestamp = (
f"left(to_char(least('{max_timestamp}'::timestamp, {timestamp})"
f"+ interval '{interval}', 'YYYY-mm-dd HH24:MI:SS.US'),"
f"length(to_char(least('{max_timestamp}'::timestamp, {timestamp})"
f"+ interval '{interval}', 'YYYY-mm-dd HH24:MI:SS.US')) - (6-{coltype.precision}))"
)
padded = _add_padding(coltype, rounded_timestamp)
return f"{null_case_begin} {padded} {null_case_end}"
# TODO years with > 4 digits not padded correctly
# current w/ precision 6: 294276-12-31 23:59:59.0000
# should be 294276-12-31 23:59:59.000000
else:
rounded_timestamp = f"to_char({value}::timestamp(6), 'YYYY-mm-dd HH24:MI:SS.US')"
padded = _add_padding(coltype, rounded_timestamp)
return padded
def normalize_number(self, value: str, coltype: FractionalType) -> str:
return self.to_string(f"{value}::decimal(38, {coltype.precision})")
def normalize_boolean(self, value: str, _coltype: Boolean) -> str:
return self.to_string(f"{value}::int")
def normalize_json(self, value: str, _coltype: JSON) -> str:
return f"{value}::text"
@attrs.define(frozen=False, init=False, kw_only=True)
class PostgreSQL(ThreadedDatabase):
DIALECT_CLASS: ClassVar[Type[BaseDialect]] = PostgresqlDialect
SUPPORTS_UNIQUE_CONSTAINT = True
CONNECT_URI_HELP = "postgresql://<user>:<password>@<host>/<database>"
CONNECT_URI_PARAMS = ["database?"]
_args: Dict[str, Any]
_conn: Any
def __init__(self, *, thread_count, **kw) -> None:
super().__init__(thread_count=thread_count)
self._args = kw
self.default_schema = "public"
def create_connection(self):
if not self._args:
self._args["host"] = None # psycopg2 requires 1+ arguments
pg = import_postgresql()
try:
self._args["password"] = unquote(self._args["password"])
self._conn = pg.connect(
**self._args, keepalives=1, keepalives_idle=5, keepalives_interval=2, keepalives_count=2
)
if SESSION_TIME_ZONE:
self._conn.cursor().execute(f"SET TIME ZONE '{SESSION_TIME_ZONE}'")
return self._conn
except pg.OperationalError as e:
raise ConnectError(*e.args) from e
def select_table_schema(self, path: DbPath) -> str:
database, schema, table = self._normalize_table_path(path)
info_schema_path = ["information_schema", "columns"]
if database:
info_schema_path.insert(0, database)
return f"""SELECT column_name, data_type, datetime_precision,
-- see comment for DEFAULT_NUMERIC_PRECISION
CASE
WHEN data_type = 'numeric'
THEN coalesce(numeric_precision, 131072 + {self.dialect.DEFAULT_NUMERIC_PRECISION})
ELSE numeric_precision
END AS numeric_precision,
CASE
WHEN data_type = 'numeric'
THEN coalesce(numeric_scale, {self.dialect.DEFAULT_NUMERIC_PRECISION})
ELSE numeric_scale
END AS numeric_scale
FROM {'.'.join(info_schema_path)}
WHERE table_name = '{table}' AND table_schema = '{schema}'
"""
def select_table_unique_columns(self, path: DbPath) -> str:
database, schema, table = self._normalize_table_path(path)
info_schema_path = ["information_schema", "key_column_usage"]
if database:
info_schema_path.insert(0, database)
return (
"SELECT column_name "
f"FROM {'.'.join(info_schema_path)} "
f"WHERE table_name = '{table}' AND table_schema = '{schema}'"
)
def _normalize_table_path(self, path: DbPath) -> DbPath:
if len(path) == 1:
return None, self.default_schema, path[0]
elif len(path) == 2:
return None, path[0], path[1]
elif len(path) == 3:
return path
raise ValueError(
f"{self.name}: Bad table path for {self}: '{'.'.join(path)}'. Expected format: table, schema.table, or database.schema.table"
)
def close(self):
super().close()
if self._conn is not None:
self._conn.close()