googleapis · Jul 9, 2024 · Jul 9, 2024 · Jul 10, 2024 · Jul 10, 2024 · Jul 11, 2024
diff --git a/.github/.OwlBot.lock.yaml b/.github/.OwlBot.lock.yaml
@@ -13,5 +13,5 @@
 # limitations under the License.
 docker:
   image: gcr.io/cloud-devrel-public-resources/owlbot-python:latest
-  digest: sha256:d3de8a02819f65001effcbd3ea76ce97e9bcff035c7a89457f40f892c87c5b32
-# created: 2024-07-03T17:43:00.77142528Z
+  digest: sha256:52210e0e0559f5ea8c52be148b33504022e1faef4e95fbe4b32d68022af2fa7e
+# created: 2024-07-08T19:25:35.862283192Z
diff --git a/.kokoro/docker/docs/Dockerfile b/.kokoro/docker/docs/Dockerfile
@@ -12,7 +12,7 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-from ubuntu:22.04
+from ubuntu:24.04
 
 ENV DEBIAN_FRONTEND noninteractive
 
@@ -40,7 +40,6 @@ RUN apt-get update \
     libssl-dev \
     libsqlite3-dev \
     portaudio19-dev \
-    python3-distutils \
     redis-server \
     software-properties-common \
     ssh \
@@ -60,18 +59,22 @@ RUN apt-get update \
   && rm -rf /var/lib/apt/lists/* \
   && rm -f /var/cache/apt/archives/*.deb
 
-###################### Install python 3.9.13
 
-# Download python 3.9.13
-RUN wget https://www.python.org/ftp/python/3.9.13/Python-3.9.13.tgz
+###################### Install python 3.10.14 for docs/docfx session
+
+# Download python 3.10.14
+RUN wget https://www.python.org/ftp/python/3.10.14/Python-3.10.14.tgz
 
 # Extract files
-RUN tar -xvf Python-3.9.13.tgz
+RUN tar -xvf Python-3.10.14.tgz
 
-# Install python 3.9.13
-RUN ./Python-3.9.13/configure --enable-optimizations
+# Install python 3.10.14
+RUN ./Python-3.10.14/configure --enable-optimizations
 RUN make altinstall
 
+RUN python3.10 -m venv /venv
+ENV PATH /venv/bin:$PATH
+
 ###################### Install pip
 RUN wget -O /tmp/get-pip.py 'https://bootstrap.pypa.io/get-pip.py' \
   && python3 /tmp/get-pip.py \
@@ -84,4 +87,4 @@ RUN python3 -m pip
 COPY requirements.txt /requirements.txt
 RUN python3 -m pip install --require-hashes -r requirements.txt
 
-CMD ["python3.8"]
+CMD ["python3.10"]
diff --git a/.kokoro/docker/docs/requirements.txt b/.kokoro/docker/docs/requirements.txt
@@ -4,9 +4,9 @@
 #
 #    pip-compile --allow-unsafe --generate-hashes requirements.in
 #
-argcomplete==3.2.3 \
-    --hash=sha256:bf7900329262e481be5a15f56f19736b376df6f82ed27576fa893652c5de6c23 \
-    --hash=sha256:c12355e0494c76a2a7b73e3a59b09024ca0ba1e279fb9ed6c1b82d5b74b6a70c
+argcomplete==3.4.0 \
+    --hash=sha256:69a79e083a716173e5532e0fa3bef45f793f4e61096cf52b5a42c0211c8b8aa5 \
+    --hash=sha256:c2abcdfe1be8ace47ba777d4fce319eb13bf8ad9dace8d085dcad6eded88057f
     # via nox
 colorlog==6.8.2 \
     --hash=sha256:3e3e079a41feb5a1b64f978b5ea4f46040a94f11f0e8bbb8261e3dbbeca64d44 \
@@ -16,23 +16,27 @@ distlib==0.3.8 \
     --hash=sha256:034db59a0b96f8ca18035f36290806a9a6e6bd9d1ff91e45a7f172eb17e51784 \
     --hash=sha256:1530ea13e350031b6312d8580ddb6b27a104275a31106523b8f123787f494f64
     # via virtualenv
-filelock==3.13.1 \
-    --hash=sha256:521f5f56c50f8426f5e03ad3b281b490a87ef15bc6c526f168290f0c7148d44e \
-    --hash=sha256:57dbda9b35157b05fb3e58ee91448612eb674172fab98ee235ccb0b5bee19a1c
+filelock==3.15.4 \
+    --hash=sha256:2207938cbc1844345cb01a5a95524dae30f0ce089eba5b00378295a17e3e90cb \
+    --hash=sha256:6ca1fffae96225dab4c6eaf1c4f4f28cd2568d3ec2a44e15a08520504de468e7
     # via virtualenv
-nox==2024.3.2 \
-    --hash=sha256:e53514173ac0b98dd47585096a55572fe504fecede58ced708979184d05440be \
-    --hash=sha256:f521ae08a15adbf5e11f16cb34e8d0e6ea521e0b92868f684e91677deb974553
+nox==2024.4.15 \
+    --hash=sha256:6492236efa15a460ecb98e7b67562a28b70da006ab0be164e8821177577c0565 \
+    --hash=sha256:ecf6700199cdfa9e5ea0a41ff5e6ef4641d09508eda6edb89d9987864115817f
     # via -r requirements.in
-packaging==24.0 \
-    --hash=sha256:2ddfb553fdf02fb784c234c7ba6ccc288296ceabec964ad2eae3777778130bc5 \
-    --hash=sha256:eb82c5e3e56209074766e6885bb04b8c38a0c015d0a30036ebe7ece34c9989e9
+packaging==24.1 \
+    --hash=sha256:026ed72c8ed3fcce5bf8950572258698927fd1dbda10a5e981cdf0ac37f4f002 \
+    --hash=sha256:5b8f2217dbdbd2f7f384c41c628544e6d52f2d0f53c6d0c3ea61aa5d1d7ff124
     # via nox
-platformdirs==4.2.0 \
-    --hash=sha256:0614df2a2f37e1a662acbd8e2b25b92ccf8632929bc6d43467e17fe89c75e068 \
-    --hash=sha256:ef0cc731df711022c174543cb70a9b5bd22e5a9337c8624ef2c2ceb8ddad8768
+platformdirs==4.2.2 \
+    --hash=sha256:2d7a1657e36a80ea911db832a8a6ece5ee53d8de21edd5cc5879af6530b1bfee \
+    --hash=sha256:38b7b51f512eed9e84a22788b4bce1de17c0adb134d6becb09836e37d8654cd3
     # via virtualenv
-virtualenv==20.25.1 \
-    --hash=sha256:961c026ac520bac5f69acb8ea063e8a4f071bcc9457b9c1f28f6b085c511583a \
-    --hash=sha256:e08e13ecdca7a0bd53798f356d5831434afa5b07b93f0abdf0797b7a06ffe197
+tomli==2.0.1 \
+    --hash=sha256:939de3e7a6161af0c887ef91b7d41a53e7c5a1ca976325f429cb46ea9bc30ecc \
+    --hash=sha256:de526c12914f0c550d15924c62d72abc48d6fe7364aa87328337a31007fe8a4f
+    # via nox
+virtualenv==20.26.3 \
+    --hash=sha256:4c43a2a236279d9ea36a0d76f98d84bd6ca94ac4e0f4a3b9d46d05e10fea542a \
+    --hash=sha256:8cc4a31139e796e9a7de2cd5cf2489de1217193116a8fd42328f1bd65f434589
     # via nox
diff --git a/.kokoro/requirements.txt b/.kokoro/requirements.txt
@@ -20,9 +20,9 @@ cachetools==5.3.3 \
     --hash=sha256:0abad1021d3f8325b2fc1d2e9c8b9c9d57b04c3932657a72465447332c24d945 \
     --hash=sha256:ba29e2dfa0b8b556606f097407ed1aa62080ee108ab0dc5ec9d6a723a007d105
     # via google-auth
-certifi==2024.6.2 \
-    --hash=sha256:3cd43f1c6fa7dedc5899d69d3ad0398fd018ad1a17fba83ddaf78aa46c747516 \
-    --hash=sha256:ddc6c8ce995e6987e7faf5e3f1b02b302836a0e5d98ece18392cb1a36c72ad56
+certifi==2024.7.4 \
+    --hash=sha256:5a1e7645bc0ec61a09e26c36f6106dd4cf40c6db3a1fb6352b0244e7fb057c7b \
+    --hash=sha256:c198e21b1289c2ab85ee4e67bb4b4ef3ead0892059901a8d5b622f24a1101e90
     # via requests
 cffi==1.16.0 \
     --hash=sha256:0c9ef6ff37e974b73c25eecc13952c55bceed9112be2d9d938ded8e856138bcc \
@@ -371,23 +371,23 @@ more-itertools==10.3.0 \
     # via
     #   jaraco-classes
     #   jaraco-functools
-nh3==0.2.17 \
-    --hash=sha256:0316c25b76289cf23be6b66c77d3608a4fdf537b35426280032f432f14291b9a \
-    --hash=sha256:1a814dd7bba1cb0aba5bcb9bebcc88fd801b63e21e2450ae6c52d3b3336bc911 \
-    --hash=sha256:1aa52a7def528297f256de0844e8dd680ee279e79583c76d6fa73a978186ddfb \
-    --hash=sha256:22c26e20acbb253a5bdd33d432a326d18508a910e4dcf9a3316179860d53345a \
-    --hash=sha256:40015514022af31975c0b3bca4014634fa13cb5dc4dbcbc00570acc781316dcc \
-    --hash=sha256:40d0741a19c3d645e54efba71cb0d8c475b59135c1e3c580f879ad5514cbf028 \
-    --hash=sha256:551672fd71d06cd828e282abdb810d1be24e1abb7ae2543a8fa36a71c1006fe9 \
-    --hash=sha256:66f17d78826096291bd264f260213d2b3905e3c7fae6dfc5337d49429f1dc9f3 \
-    --hash=sha256:85cdbcca8ef10733bd31f931956f7fbb85145a4d11ab9e6742bbf44d88b7e351 \
-    --hash=sha256:a3f55fabe29164ba6026b5ad5c3151c314d136fd67415a17660b4aaddacf1b10 \
-    --hash=sha256:b4427ef0d2dfdec10b641ed0bdaf17957eb625b2ec0ea9329b3d28806c153d71 \
-    --hash=sha256:ba73a2f8d3a1b966e9cdba7b211779ad8a2561d2dba9674b8a19ed817923f65f \
-    --hash=sha256:c21bac1a7245cbd88c0b0e4a420221b7bfa838a2814ee5bb924e9c2f10a1120b \
-    --hash=sha256:c551eb2a3876e8ff2ac63dff1585236ed5dfec5ffd82216a7a174f7c5082a78a \
-    --hash=sha256:c790769152308421283679a142dbdb3d1c46c79c823008ecea8e8141db1a2062 \
-    --hash=sha256:d7a25fd8c86657f5d9d576268e3b3767c5cd4f42867c9383618be8517f0f022a
+nh3==0.2.18 \
+    --hash=sha256:0411beb0589eacb6734f28d5497ca2ed379eafab8ad8c84b31bb5c34072b7164 \
+    --hash=sha256:14c5a72e9fe82aea5fe3072116ad4661af5cf8e8ff8fc5ad3450f123e4925e86 \
+    --hash=sha256:19aaba96e0f795bd0a6c56291495ff59364f4300d4a39b29a0abc9cb3774a84b \
+    --hash=sha256:34c03fa78e328c691f982b7c03d4423bdfd7da69cd707fe572f544cf74ac23ad \
+    --hash=sha256:36c95d4b70530b320b365659bb5034341316e6a9b30f0b25fa9c9eff4c27a204 \
+    --hash=sha256:3a157ab149e591bb638a55c8c6bcb8cdb559c8b12c13a8affaba6cedfe51713a \
+    --hash=sha256:42c64511469005058cd17cc1537578eac40ae9f7200bedcfd1fc1a05f4f8c200 \
+    --hash=sha256:5f36b271dae35c465ef5e9090e1fdaba4a60a56f0bb0ba03e0932a66f28b9189 \
+    --hash=sha256:6955369e4d9f48f41e3f238a9e60f9410645db7e07435e62c6a9ea6135a4907f \
+    --hash=sha256:7b7c2a3c9eb1a827d42539aa64091640bd275b81e097cd1d8d82ef91ffa2e811 \
+    --hash=sha256:8ce0f819d2f1933953fca255db2471ad58184a60508f03e6285e5114b6254844 \
+    --hash=sha256:94a166927e53972a9698af9542ace4e38b9de50c34352b962f4d9a7d4c927af4 \
+    --hash=sha256:a7f1b5b2c15866f2db413a3649a8fe4fd7b428ae58be2c0f6bca5eefd53ca2be \
+    --hash=sha256:c8b3a1cebcba9b3669ed1a84cc65bf005728d2f0bc1ed2a6594a992e817f3a50 \
+    --hash=sha256:de3ceed6e661954871d6cd78b410213bdcb136f79aafe22aa7182e028b8c7307 \
+    --hash=sha256:f0eca9ca8628dbb4e916ae2491d72957fdd35f7a5d326b7032a345f111ac07fe
     # via readme-renderer
 nox==2024.4.15 \
     --hash=sha256:6492236efa15a460ecb98e7b67562a28b70da006ab0be164e8821177577c0565 \
@@ -460,9 +460,9 @@ python-dateutil==2.9.0.post0 \
     --hash=sha256:37dd54208da7e1cd875388217d5e00ebd4179249f90fb72437e91a35459a0ad3 \
     --hash=sha256:a8b2bc7bffae282281c8140a97d3aa9c14da0b136dfe83f850eea9a5f7470427
     # via gcp-releasetool
-readme-renderer==43.0 \
-    --hash=sha256:1818dd28140813509eeed8d62687f7cd4f7bad90d4db586001c5dc09d4fde311 \
-    --hash=sha256:19db308d86ecd60e5affa3b2a98f017af384678c63c88e5d4556a380e674f3f9
+readme-renderer==44.0 \
+    --hash=sha256:2fbca89b81a08526aadf1357a8c2ae889ec05fb03f5da67f9769c9a592166151 \
+    --hash=sha256:8712034eabbfa6805cacf1402b4eeb2a73028f72d1166d6f5cb7f9c047c5d1e1
     # via twine
 requests==2.32.3 \
     --hash=sha256:55365417734eb18255590a9ff9eb97e9e1da868d4ccd6402399eaf68af20a760 \

diff --git a/CHANGELOG.md b/CHANGELOG.md
@@ -4,6 +4,33 @@
 
 [1]: https://pypi.org/project/bigframes/#history
 
+## [1.12.0](https://github.com/googleapis/python-bigquery-dataframes/compare/v1.11.1...v1.12.0) (2024-07-31)
+
+
+### Features
+
+* Add bigframes-mode label to query jobs ([#832](https://github.com/googleapis/python-bigquery-dataframes/issues/832)) ([c9eaff0](https://github.com/googleapis/python-bigquery-dataframes/commit/c9eaff0a1a0731b28f4c67bca5606db12a47c8c0))
+* Add config option to set partial ordering mode ([#855](https://github.com/googleapis/python-bigquery-dataframes/issues/855)) ([823c0ce](https://github.com/googleapis/python-bigquery-dataframes/commit/823c0ce57611c0918a9e9999638d7393337fe9af))
+* Add stratify param support to ml.model_selection.train_test_split method ([#815](https://github.com/googleapis/python-bigquery-dataframes/issues/815)) ([27f8631](https://github.com/googleapis/python-bigquery-dataframes/commit/27f8631be81a3e136cfeb8904558bb4f3f5caa05))
+* Add streaming.StreamingDataFrame class ([#864](https://github.com/googleapis/python-bigquery-dataframes/issues/864)) ([a7d7197](https://github.com/googleapis/python-bigquery-dataframes/commit/a7d7197a32c55b989ae4ea8f6cf6e1c0f7184cd4))
+* Allow DataFrame.join for self-join on Null index ([#860](https://github.com/googleapis/python-bigquery-dataframes/issues/860)) ([e950533](https://github.com/googleapis/python-bigquery-dataframes/commit/e95053372c36ea5a91a2d7295c1a3a3671181670))
+* Support remote function cleanup with `session.close` ([#818](https://github.com/googleapis/python-bigquery-dataframes/issues/818)) ([ed06436](https://github.com/googleapis/python-bigquery-dataframes/commit/ed06436612c0d46f190f79721416d473bde7e2f4))
+* Support to_csv/parquet/json to local files/objects ([#858](https://github.com/googleapis/python-bigquery-dataframes/issues/858)) ([d0ab9cc](https://github.com/googleapis/python-bigquery-dataframes/commit/d0ab9cc47298bdde638299baecac9dffd7841ede))
+
+
+### Bug Fixes
+
+* Fewer relation joins from df self-operations ([#823](https://github.com/googleapis/python-bigquery-dataframes/issues/823)) ([0d24f73](https://github.com/googleapis/python-bigquery-dataframes/commit/0d24f737041c7dd70253ebb4baa8d8ef67bd4f1d))
+* Fix 'sql' property for null index ([#844](https://github.com/googleapis/python-bigquery-dataframes/issues/844)) ([1b6a556](https://github.com/googleapis/python-bigquery-dataframes/commit/1b6a556206a7a66283339d827ab12db2753521e2))
+* Fix unordered mode using ordered path to print frame ([#839](https://github.com/googleapis/python-bigquery-dataframes/issues/839)) ([93785cb](https://github.com/googleapis/python-bigquery-dataframes/commit/93785cb48be4a2eb8770129148bd0b897fed4ee7))
+* Reduce redundant `remote_function` deployments ([#856](https://github.com/googleapis/python-bigquery-dataframes/issues/856)) ([cbf2d42](https://github.com/googleapis/python-bigquery-dataframes/commit/cbf2d42e4d961a7537381a9c3b28a8b463ad8f74))
+
+
+### Documentation
+
+* Add partner attribution steps to integrations sample notebook ([#835](https://github.com/googleapis/python-bigquery-dataframes/issues/835)) ([d7b333f](https://github.com/googleapis/python-bigquery-dataframes/commit/d7b333fa26acddaeb5ccca4f81b1d624dff03ba2))
+* Make `get_global_session`/`close_session`/`reset_session` appears in the docs ([#847](https://github.com/googleapis/python-bigquery-dataframes/issues/847)) ([01d6bbb](https://github.com/googleapis/python-bigquery-dataframes/commit/01d6bbb7479da706dc62bb5e7d51dc28a4042812))
+
 ## [1.11.1](https://github.com/googleapis/python-bigquery-dataframes/compare/v1.11.0...v1.11.1) (2024-07-08)
 
 

diff --git a/bigframes/_config/bigquery_options.py b/bigframes/_config/bigquery_options.py
@@ -16,7 +16,8 @@
 
 from __future__ import annotations
 
-from typing import Optional
+from enum import Enum
+from typing import Literal, Optional
 import warnings
 
 import google.api_core.exceptions
@@ -26,6 +27,12 @@
 import bigframes.constants
 import bigframes.exceptions
 
+
+class OrderingMode(Enum):
+    STRICT = "strict"
+    PARTIAL = "partial"
+
+
 SESSION_STARTED_MESSAGE = (
     "Cannot change '{attribute}' once a session has started. "
     "Call bigframes.pandas.close_session() first, if you are using the bigframes.pandas API."
@@ -57,6 +64,14 @@ def _validate_location(value: Optional[str]):
         )
 
 
+def _validate_ordering_mode(value: str) -> OrderingMode:
+    if value.casefold() == OrderingMode.STRICT.value.casefold():
+        return OrderingMode.STRICT
+    if value.casefold() == OrderingMode.PARTIAL.value.casefold():
+        return OrderingMode.PARTIAL
+    raise ValueError("Ordering mode must be one of 'strict' or 'partial'.")
+
+
 class BigQueryOptions:
     """Encapsulates configuration for working with a session."""
 
@@ -71,7 +86,7 @@ def __init__(
         kms_key_name: Optional[str] = None,
         skip_bq_connection_check: bool = False,
         *,
-        _strictly_ordered: bool = True,
+        ordering_mode: Literal["strict", "partial"] = "strict",
     ):
         self._credentials = credentials
         self._project = project
@@ -82,8 +97,8 @@ def __init__(
         self._kms_key_name = kms_key_name
         self._skip_bq_connection_check = skip_bq_connection_check
         self._session_started = False
-        # Determines the ordering strictness for the session. For internal use only.
-        self._strictly_ordered_internal = _strictly_ordered
+        # Determines the ordering strictness for the session.
+        self._ordering_mode = _validate_ordering_mode(ordering_mode)
 
     @property
     def application_name(self) -> Optional[str]:
@@ -241,6 +256,10 @@ def kms_key_name(self, value: str):
         self._kms_key_name = value
 
     @property
-    def _strictly_ordered(self) -> bool:
-        """Internal use only. Controls whether total row order is always maintained for DataFrame/Series."""
-        return self._strictly_ordered_internal
+    def ordering_mode(self) -> Literal["strict", "partial"]:
+        """Controls whether total row order is always maintained for DataFrame/Series."""
+        return self._ordering_mode.value
+
+    @ordering_mode.setter
+    def ordering_mode(self, ordering_mode: Literal["strict", "partial"]) -> None:
+        self._ordering_mode = _validate_ordering_mode(ordering_mode)
diff --git a/bigframes/constants.py b/bigframes/constants.py
@@ -99,3 +99,5 @@
 
 # BigQuery default is 10000, leave 100 for overhead
 MAX_COLUMNS = 9900
+
+SUGGEST_PEEK_PREVIEW = "Use .peek(n) to preview n arbitrary rows."
diff --git a/bigframes/core/__init__.py b/bigframes/core/__init__.py
@@ -147,7 +147,7 @@ def _compiled_schema(self) -> schemata.ArraySchema:
     def as_cached(
         self: ArrayValue,
         cache_table: google.cloud.bigquery.Table,
-        ordering: Optional[orderings.TotalOrdering],
+        ordering: Optional[orderings.RowOrdering],
     ) -> ArrayValue:
         """
         Replace the node with an equivalent one that references a tabel where the value has been materialized to.
@@ -194,7 +194,7 @@ def promote_offsets(self, col_id: str) -> ArrayValue:
         """
         Convenience function to promote copy of column offsets to a value column. Can be used to reset index.
         """
-        if not self.session._strictly_ordered:
+        if self.node.order_ambiguous and not self.session._strictly_ordered:
             raise ValueError("Generating offsets not supported in unordered mode")
         return ArrayValue(nodes.PromoteOffsetsNode(child=self.node, col_id=col_id))
 
@@ -346,7 +346,7 @@ def project_window_op(
         """
         # TODO: Support non-deterministic windowing
         if window_spec.row_bounded or not op.order_independent:
-            if not self.session._strictly_ordered:
+            if self.node.order_ambiguous and not self.session._strictly_ordered:
                 raise ValueError(
                     "Order-dependent windowed ops not supported in unordered mode"
                 )
@@ -460,9 +460,9 @@ def _cross_join_w_labels(
             conditions=(), mappings=(*labels_mappings, *table_mappings), type="cross"
         )
         if join_side == "left":
-            joined_array = self.join(labels_array, join_def=join)
+            joined_array = self.relational_join(labels_array, join_def=join)
         else:
-            joined_array = labels_array.join(self, join_def=join)
+            joined_array = labels_array.relational_join(self, join_def=join)
         return joined_array
 
     def _create_unpivot_labels_array(
@@ -485,30 +485,27 @@ def _create_unpivot_labels_array(
 
         return ArrayValue.from_pyarrow(pa.Table.from_pylist(rows), session=self.session)
 
-    def join(
+    def relational_join(
         self,
         other: ArrayValue,
         join_def: join_def.JoinDefinition,
-        allow_row_identity_join: bool = False,
-    ):
+    ) -> ArrayValue:
         join_node = nodes.JoinNode(
             left_child=self.node,
             right_child=other.node,
             join=join_def,
-            allow_row_identity_join=allow_row_identity_join,
         )
-        if allow_row_identity_join:
-            return ArrayValue(bigframes.core.rewrite.maybe_rewrite_join(join_node))
         return ArrayValue(join_node)
 
     def try_align_as_projection(
         self,
         other: ArrayValue,
         join_type: join_def.JoinType,
+        join_keys: typing.Tuple[join_def.CoalescedColumnMapping, ...],
         mappings: typing.Tuple[join_def.JoinColumnMapping, ...],
     ) -> typing.Optional[ArrayValue]:
         result = bigframes.core.rewrite.join_as_projection(
-            self.node, other.node, mappings, join_type
+            self.node, other.node, join_keys, mappings, join_type
         )
         if result is not None:
             return ArrayValue(result)
Original file line number	Diff line number	Diff line change
		@@ -99,3 +99,5 @@

		# BigQuery default is 10000, leave 100 for overhead
		MAX_COLUMNS = 9900

		SUGGEST_PEEK_PREVIEW = "Use .peek(n) to preview n arbitrary rows."