fix: revert change default read_consistency_interval=5s (#2327)

This reverts commit a547c523c2 or #2281

The current implementation can cause panics and performance degradation.
I will bring this back with more testing in
https://github.com/lancedb/lancedb/pull/2311

<!-- This is an auto-generated comment: release notes by coderabbit.ai
-->
## Summary by CodeRabbit

- **Documentation**
- Enhanced clarity on read consistency settings with updated
descriptions and default behavior.
- Removed outdated warnings about eventual consistency from the
troubleshooting guide.

- **Refactor**
- Streamlined the handling of the read consistency interval across
integrations, now defaulting to "None" for improved performance.
  - Simplified internal logic to offer a more consistent experience.

- **Tests**
- Updated test expectations to reflect the new default representation
for the read consistency interval.
- Removed redundant tests related to "no consistency" settings for
streamlined testing.
<!-- end of auto-generated comment: release notes by coderabbit.ai -->

---------

Co-authored-by: coderabbitai[bot] <136622811+coderabbitai[bot]@users.noreply.github.com>

python/python/lancedb/__init__.py

@@ -26,7 +26,7 @@ def connect(
     api_key: Optional[str] = None,
     region: str = "us-east-1",
     host_override: Optional[str] = None,
-    read_consistency_interval: Optional[timedelta] = timedelta(seconds=5),
+    read_consistency_interval: Optional[timedelta] = None,
     request_thread_pool: Optional[Union[int, ThreadPoolExecutor]] = None,
     client_config: Union[ClientConfig, Dict[str, Any], None] = None,
     storage_options: Optional[Dict[str, str]] = None,
@@ -49,8 +49,9 @@ def connect(
     read_consistency_interval: timedelta, default None
         (For LanceDB OSS only)
         The interval at which to check for updates to the table from other
-        processes. If None, then consistency is not checked. For strong consistency,
-        set this to zero seconds. Then every read will check for updates from other
+        processes. If None, then consistency is not checked. For performance
+        reasons, this is the default. For strong consistency, set this to
+        zero seconds. Then every read will check for updates from other
         processes. As a compromise, you can set this to a non-zero timedelta
         for eventual consistency. If more than that interval has passed since
         the last check, then the table will be checked for updates. Note: this
@@ -121,7 +122,7 @@ async def connect_async(
     api_key: Optional[str] = None,
     region: str = "us-east-1",
     host_override: Optional[str] = None,
-    read_consistency_interval: Optional[timedelta] = timedelta(seconds=5),
+    read_consistency_interval: Optional[timedelta] = None,
     client_config: Optional[Union[ClientConfig, Dict[str, Any]]] = None,
     storage_options: Optional[Dict[str, str]] = None,
 ) -> AsyncConnection:
@@ -142,8 +143,9 @@ async def connect_async(
     read_consistency_interval: timedelta, default None
         (For LanceDB OSS only)
         The interval at which to check for updates to the table from other
-        processes. If None, then consistency is not checked. For strong consistency,
-        set this to zero seconds. Then every read will check for updates from other
+        processes. If None, then consistency is not checked. For performance
+        reasons, this is the default. For strong consistency, set this to
+        zero seconds. Then every read will check for updates from other
         processes. As a compromise, you can set this to a non-zero timedelta
         for eventual consistency. If more than that interval has passed since
         the last check, then the table will be checked for updates. Note: this

python/python/lancedb/db.py

@@ -6,7 +6,6 @@ from __future__ import annotations
 
 from abc import abstractmethod
 from pathlib import Path
-from datetime import timedelta
 from typing import TYPE_CHECKING, Dict, Iterable, List, Literal, Optional, Union
 
 from lancedb.embeddings.registry import EmbeddingFunctionRegistry
@@ -33,6 +32,7 @@ import deprecation
 if TYPE_CHECKING:
     import pyarrow as pa
     from .pydantic import LanceModel
+    from datetime import timedelta
 
     from ._lancedb import Connection as LanceDbConnection
     from .common import DATA, URI
@@ -318,8 +318,9 @@ class LanceDBConnection(DBConnection):
         The root uri of the database.
     read_consistency_interval: timedelta, default None
         The interval at which to check for updates to the table from other
-        processes. If None, then consistency is not checked. For strong consistency,
-        set this to zero seconds. Then every read will check for updates from other
+        processes. If None, then consistency is not checked. For performance
+        reasons, this is the default. For strong consistency, set this to
+        zero seconds. Then every read will check for updates from other
         processes. As a compromise, you can set this to a non-zero timedelta
         for eventual consistency. If more than that interval has passed since
         the last check, then the table will be checked for updates. Note: this
@@ -351,7 +352,7 @@ class LanceDBConnection(DBConnection):
         self,
         uri: URI,
         *,
-        read_consistency_interval: Optional[timedelta] = timedelta(seconds=5),
+        read_consistency_interval: Optional[timedelta] = None,
         storage_options: Optional[Dict[str, str]] = None,
     ):
         if not isinstance(uri, Path):

python/python/tests/docs/test_guide_tables.py

@@ -315,11 +315,6 @@ def test_table():
     db = lancedb.connect(uri, read_consistency_interval=timedelta(seconds=5))
     tbl = db.open_table("test_table")
     # --8<-- [end:table_eventual_consistency]
-    # --8<-- [start:table_no_consistency]
-    uri = "data/sample-lancedb"
-    db = lancedb.connect(uri, read_consistency_interval=None)
-    tbl = db.open_table("test_table")
-    # --8<-- [end:table_no_consistency]
     # --8<-- [start:table_checkout_latest]
     tbl = db.open_table("test_table")
 
@@ -574,12 +569,6 @@ async def test_table_async():
     )
     async_tbl = await async_db.open_table("test_table_async")
     # --8<-- [end:table_async_eventual_consistency]
-    # --8<-- [start:table_async_no_consistency]
-    uri = "data/sample-lancedb"
-    async_db = await lancedb.connect_async(uri, read_consistency_interval=None)
-    async_tbl = await async_db.open_table("test_table_async")
-    # --8<-- [end:table_async_no_consistency]
-
     # --8<-- [start:table_async_checkout_latest]
     async_tbl = await async_db.open_table("test_table_async")
 

python/python/tests/test_db.py

@@ -3,6 +3,7 @@
 
 
 import re
+from datetime import timedelta
 import os
 
 import lancedb
@@ -298,11 +299,13 @@ def test_create_exist_ok(tmp_db: lancedb.DBConnection):
 @pytest.mark.asyncio
 async def test_connect(tmp_path):
     db = await lancedb.connect_async(tmp_path)
-    assert str(db) == f"ListingDatabase(uri={tmp_path}, read_consistency_interval=5s)"
-
-    db = await lancedb.connect_async(tmp_path, read_consistency_interval=None)
     assert str(db) == f"ListingDatabase(uri={tmp_path}, read_consistency_interval=None)"
 
+    db = await lancedb.connect_async(
+        tmp_path, read_consistency_interval=timedelta(seconds=5)
+    )
+    assert str(db) == f"ListingDatabase(uri={tmp_path}, read_consistency_interval=5s)"
+
 
 @pytest.mark.asyncio
 async def test_close(mem_db_async: lancedb.AsyncConnection):
@@ -450,7 +453,7 @@ async def test_open_table(tmp_path):
     assert tbl.name == "test"
     assert (
         re.search(
-            r"NativeTable\(test, uri=.*test\.lance, read_consistency_interval=5s\)",
+            r"NativeTable\(test, uri=.*test\.lance, read_consistency_interval=None\)",
             str(tbl),
         )
         is not None

python/python/tests/test_table.py

@@ -32,11 +32,7 @@ def test_basic(mem_db: DBConnection):
     table = mem_db.create_table("test", data=data)
 
     assert table.name == "test"
-    assert (
-        "LanceTable(name='test', version=1, "
-        "read_consistency_interval=datetime.timedelta(seconds=5), "
-        "_conn=LanceDBConnection("
-    ) in repr(table)
+    assert "LanceTable(name='test', version=1, _conn=LanceDBConnection(" in repr(table)
     expected_schema = pa.schema(
         {
             "vector": pa.list_(pa.float32(), 2),