sqlalchemy.engine.result.ChunkedIteratorResult

class documentation

class ChunkedIteratorResult(IteratorResult):

An .IteratorResult that works from an iterator-producing callable.

The given chunks argument is a function that is given a number of rows to return in each chunk, or None for all rows. The function should then return an un-consumed iterator of lists, each list of the requested size.

The function can be called at any time again, in which case it should continue from the same result set but adjust the chunk size as given.

New in version 1.4.

Method	`__init__`	Undocumented
Method	`_fetchmany_impl`	Undocumented
Method	`_soft_close`	Undocumented
Method	`yield_per`	Configure the row-fetching strategy to fetch num rows at a time.
Instance Variable	`_metadata`	Undocumented
Instance Variable	`_source_supports_scalars`	Undocumented
Instance Variable	`_yield_per`	Undocumented
Instance Variable	`chunks`	Undocumented
Instance Variable	`dynamic_yield_per`	Undocumented
Instance Variable	`iterator`	Undocumented
Instance Variable	`raw`	Undocumented

Inherited from IteratorResult:

Method	`_fetchall_impl`	Undocumented
Method	`_fetchiter_impl`	Undocumented
Method	`_fetchone_impl`	Undocumented
Method	`_raise_hard_closed`	Undocumented
Method	`_raw_row_iterator`	Return a safe iterator that yields raw row data.
Instance Variable	`_hard_closed`	Undocumented

Inherited from Result (via IteratorResult):

Method	`__iter__`	Undocumented
Method	`__next__`	Undocumented
Method	`_getter`	return a callable that will retrieve the given key from a `.Row`.
Method	`_tuple_getter`	return a callable that will retrieve the given keys from a `.Row`.
Method	`all`	Return all rows in a list.
Method	`close`	close this `_result.Result`.
Method	`columns`	Establish the columns that should be returned in each row.
Method	`fetchall`	A synonym for the `_engine.Result.all` method.
Method	`fetchmany`	Fetch many rows.
Method	`fetchone`	Fetch one row.
Method	`first`	Fetch the first row or None if no row is present.
Method	`freeze`	Return a callable object that will produce copies of this `.Result` when invoked.
Method	`mappings`	Apply a mappings filter to returned rows, returning an instance of `_result.MappingResult`.
Method	`merge`	Merge this `.Result` with other compatible result objects.
Method	`next`	Undocumented
Method	`one`	Return exactly one row or raise an exception.
Method	`one_or_none`	Return at most one result or raise an exception.
Method	`partitions`	Iterate through sub-lists of rows of the size given.
Method	`scalar`	Fetch the first column of the first row, and close the result set.
Method	`scalar_one`	Return exactly one scalar result or raise an exception.
Method	`scalar_one_or_none`	Return exactly one or no scalar result.
Method	`scalars`	Return a `_result.ScalarResult` filtering object which will return single elements rather than `_row.Row` objects.
Method	`unique`	Apply unique filtering to the objects returned by this `_engine.Result`.
Class Variable	`_attributes`	Undocumented
Class Variable	`_row_logging_fn`	Undocumented
Instance Variable	`_unique_filter_state`	Undocumented

Inherited from _WithKeys (via IteratorResult, Result):

Method keys Return an iterable view which yields the string keys that would be represented by each .Row.

Inherited from ResultInternal (via IteratorResult, Result):

Method	`_allrows`	Undocumented
Method	`_column_slices`	Undocumented
Method	`_iter_impl`	Undocumented
Method	`_iterator_getter`	Undocumented
Method	`_manyrow_getter`	Undocumented
Method	`_next_impl`	Undocumented
Method	`_onerow_getter`	Undocumented
Method	`_only_one_row`	Undocumented
Method	`_raw_all_rows`	Undocumented
Method	`_row_getter`	Undocumented
Method	`_unique_strategy`	Undocumented
Class Variable	`_post_creational_filter`	Undocumented
Class Variable	`_real_result`	Undocumented
Instance Variable	`_generate_rows`	Undocumented

Inherited from InPlaceGenerative (via IteratorResult, Result, ResultInternal):

Method _generate Undocumented

def __init__(self, cursor_metadata, chunks, source_supports_scalars=False, raw=None, dynamic_yield_per=False):

overrides sqlalchemy.engine.result.IteratorResult.__init__

Undocumented

def _fetchmany_impl(self, size=None):

overrides sqlalchemy.engine.result.IteratorResult._fetchmany_impl

Undocumented

def _soft_close(self, **kw):

overrides sqlalchemy.engine.result.IteratorResult._soft_close

Undocumented

@_generative
def yield_per(self, num):

overrides sqlalchemy.engine.result.Result.yield_per

Configure the row-fetching strategy to fetch num rows at a time.

This impacts the underlying behavior of the result when iterating over the result object, or otherwise making use of methods such as _engine.Result.fetchone that return one row at a time. Data from the underlying cursor or other data source will be buffered up to this many rows in memory, and the buffered collection will then be yielded out one row at at time or as many rows are requested. Each time the buffer clears, it will be refreshed to this many rows or as many rows remain if fewer remain.

The _engine.Result.yield_per method is generally used in conjunction with the :paramref:`_engine.Connection.execution_options.stream_results` execution option, which will allow the database dialect in use to make use of a server side cursor, if the DBAPI supports it.

Most DBAPIs do not use server side cursors by default, which means all rows will be fetched upfront from the database regardless of the _engine.Result.yield_per setting. However, _engine.Result.yield_per may still be useful in that it batches the SQLAlchemy-side processing of the raw data from the database, and additionally when used for ORM scenarios will batch the conversion of database rows into ORM entity rows.

New in version 1.4.

Parameters
num	number of rows to fetch each time the buffer is refilled. If set to a value below 1, fetches all rows for the next buffer.

_metadata =

overrides sqlalchemy.engine.result.IteratorResult._metadata

Undocumented

_source_supports_scalars =

overrides sqlalchemy.engine.result.IteratorResult._source_supports_scalars

Undocumented

_yield_per =

overrides sqlalchemy.engine.result.Result._yield_per

Undocumented

chunks =

Undocumented

dynamic_yield_per =

Undocumented

iterator =

overrides sqlalchemy.engine.result.IteratorResult.iterator

Undocumented

raw =

overrides sqlalchemy.engine.result.IteratorResult.raw

Undocumented