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feat(sqlalchemy-spanner): export MAX_SIZE constant #17922

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Merged
sakthivelmanii merged 2 commits into from
Jul 30, 2026
+26 −4
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feat(sqlalchemy-spanner): export MAX_SIZE constant #17922

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db4b93e
feat(sqlalchemy-spanner): export MAX_SIZE constant and SpannerDialect…
sakthivelmanii Jul 28, 2026
cd3f962
docs(sqlalchemy-spanner): add docstring for MAX_SIZE constant
sakthivelmanii Jul 30, 2026
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8 changes: 6 additions & 2 deletions packages/sqlalchemy-spanner/google/cloud/sqlalchemy_spanner/__init__.py
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Original file line number Diff line number Diff line change
Expand Up @@ -12,7 +12,11 @@
# See the License for the specific language governing permissions and
# limitations under the License.

from .sqlalchemy_spanner import SpannerDialect
from .sqlalchemy_spanner import MAX_SIZE, SpannerDialect
from .version import __version__

__all__ = (SpannerDialect, __version__)
__all__ = (
"MAX_SIZE",
"SpannerDialect",
"__version__",
)
8 changes: 6 additions & 2 deletions packages/sqlalchemy-spanner/google/cloud/sqlalchemy_spanner/sqlalchemy_spanner.py
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Expand Up @@ -150,7 +150,10 @@ def process(value):
selectable.CompoundSelect.INTERSECT_ALL: "INTERSECT ALL",
}

_max_size = 2621440
#: Maximum allowable character/byte length for Cloud Spanner STRING(MAX) and
#: BYTES(MAX) DDL data types (2.5 MiB = 2,621,440 bytes).
MAX_SIZE = 2621440

@olavloite olavloite Jul 30, 2026

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nit: should we consider renaming this to MAX_STRING_COLUMN_LENGTH? Or is the MAX_SIZE name a standard in SQLAlchemy? If we keep the name MAX_SIZE, can we add a docstring that explains what this max is for?

_max_size = MAX_SIZE


def int_from_size(size_str):
Expand All @@ -162,7 +165,7 @@ def int_from_size(size_str):
Returns:
int: The column length value.
"""
return _max_size if size_str == "MAX" else int(size_str)
return MAX_SIZE if size_str == "MAX" else int(size_str)


def engine_to_connection(function):
Expand Down Expand Up @@ -833,6 +836,7 @@ class SpannerDialect(DefaultDialect):
paramstyle = "format"
encoding = "utf-8"
max_identifier_length = 256
max_size = MAX_SIZE
_legacy_binary_type_literal_encoding = "utf-8"
_default_isolation_level = "SERIALIZABLE"

Expand Down
14 changes: 14 additions & 0 deletions packages/sqlalchemy-spanner/tests/unit/test_dialect.py
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Expand Up @@ -84,3 +84,17 @@ def test_get_multi_indexes_handles_null_column_orderings_array(self):
assert ("public", "my_table") in res
index_info = res[("public", "my_table")][0]
eq_(index_info["column_sorting"], {})

def test_max_size_exported(self):
"""Test MAX_SIZE export and int_from_size helper behavior."""
from google.cloud.sqlalchemy_spanner import MAX_SIZE
from google.cloud.sqlalchemy_spanner.sqlalchemy_spanner import (
_max_size,
int_from_size,
)

eq_(MAX_SIZE, 2621440)
eq_(_max_size, MAX_SIZE)
eq_(SpannerDialect.max_size, MAX_SIZE)
eq_(int_from_size("MAX"), 2621440)
eq_(int_from_size("100"), 100)
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