Merge remote-tracking branch 'origin/main' into gatekeeper/fix-3153-1

<!-- lance-gatekeeper-fix:v1 agent=5c80c44c083b3b8ad0da595419d468fc
generation=1 -->

## Root cause

The legacy synchronous Python table called `delete` on a shared, mutable
`lance.Dataset`. Concurrent table operations could hold a PyO3 borrow
while delete requested an exclusive borrow, producing `RuntimeError:
Already borrowed`. The current async-backed binding fixes this by
cloning its thread-safe Rust table handle before awaiting, but that
concurrency contract had no regression coverage.

## Fix

- Document why delete must clone the Rust table handle before entering
its async future.
- Add a barrier-synchronized regression test that deletes distinct rows
through one shared table from eight Python threads.
- Verify every delete commits exactly one row, every commit gets a
distinct version, and no rows remain.

## Validation

- `cargo check --quiet --features remote --tests --examples`
- `cargo fmt --all -- --check`
- `uv run --extra tests --extra dev ruff format --check
python/tests/test_table.py`
- `uv run --extra tests --extra dev ruff check
python/tests/test_table.py`
- `uv run --extra tests --extra dev pytest
python/tests/test_table.py::test_concurrent_deletes_are_thread_safe
python/tests/test_table.py::test_delete
python/tests/test_table.py::test_delete_expr
python/tests/test_table.py::test_delete_expr_async -q` (4 passed)
- Manual stress reproduction: 100 concurrent deletes on one table
completed at versions 2–101 with zero rows remaining.

Fixes #530

Co-authored-by: Gatefixer <313497061+lancedb-gatefixer[bot]@users.noreply.github.com>

Cargo.lock

@@ -3422,7 +3422,7 @@ checksum = "42703706b716c37f96a77aea830392ad231f44c9e9a67872fa5548707e11b11c"
 [[package]]
 name = "fsst"
 version = "10.1.0-beta.1"
-source = "git+https://github.com/lance-format/lance.git?rev=b7ef2bae3c7aeb85da637a8c3bc6643ab7d81564#b7ef2bae3c7aeb85da637a8c3bc6643ab7d81564"
+source = "git+https://github.com/lance-format/lance.git?tag=v10.1.0-beta.1#68f4d4c1d0c4871b067557c61fc405078f1ab3b7"
 dependencies = [
  "arrow-array",
  "rand 0.9.5",
@@ -4778,7 +4778,7 @@ checksum = "e037a2e1d8d5fdbd49b16a4ea09d5d6401c1f29eca5ff29d03d3824dba16256a"
 [[package]]
 name = "lance"
 version = "10.1.0-beta.1"
-source = "git+https://github.com/lance-format/lance.git?rev=b7ef2bae3c7aeb85da637a8c3bc6643ab7d81564#b7ef2bae3c7aeb85da637a8c3bc6643ab7d81564"
+source = "git+https://github.com/lance-format/lance.git?tag=v10.1.0-beta.1#68f4d4c1d0c4871b067557c61fc405078f1ab3b7"
 dependencies = [
  "arc-swap",
  "arrow",
@@ -4853,7 +4853,7 @@ dependencies = [
 [[package]]
 name = "lance-arrow"
 version = "10.1.0-beta.1"
-source = "git+https://github.com/lance-format/lance.git?rev=b7ef2bae3c7aeb85da637a8c3bc6643ab7d81564#b7ef2bae3c7aeb85da637a8c3bc6643ab7d81564"
+source = "git+https://github.com/lance-format/lance.git?tag=v10.1.0-beta.1#68f4d4c1d0c4871b067557c61fc405078f1ab3b7"
 dependencies = [
  "arrow-array",
  "arrow-buffer",
@@ -4875,7 +4875,7 @@ dependencies = [
 [[package]]
 name = "lance-arrow-scalar"
 version = "58.0.0"
-source = "git+https://github.com/lance-format/lance.git?rev=b7ef2bae3c7aeb85da637a8c3bc6643ab7d81564#b7ef2bae3c7aeb85da637a8c3bc6643ab7d81564"
+source = "git+https://github.com/lance-format/lance.git?tag=v10.1.0-beta.1#68f4d4c1d0c4871b067557c61fc405078f1ab3b7"
 dependencies = [
  "arrow-array",
  "arrow-buffer",
@@ -4889,7 +4889,7 @@ dependencies = [
 [[package]]
 name = "lance-arrow-stats"
 version = "58.0.0"
-source = "git+https://github.com/lance-format/lance.git?rev=b7ef2bae3c7aeb85da637a8c3bc6643ab7d81564#b7ef2bae3c7aeb85da637a8c3bc6643ab7d81564"
+source = "git+https://github.com/lance-format/lance.git?tag=v10.1.0-beta.1#68f4d4c1d0c4871b067557c61fc405078f1ab3b7"
 dependencies = [
  "arrow-array",
  "arrow-schema",
@@ -4899,7 +4899,7 @@ dependencies = [
 [[package]]
 name = "lance-bitpacking"
 version = "10.1.0-beta.1"
-source = "git+https://github.com/lance-format/lance.git?rev=b7ef2bae3c7aeb85da637a8c3bc6643ab7d81564#b7ef2bae3c7aeb85da637a8c3bc6643ab7d81564"
+source = "git+https://github.com/lance-format/lance.git?tag=v10.1.0-beta.1#68f4d4c1d0c4871b067557c61fc405078f1ab3b7"
 dependencies = [
  "arrayref",
  "crunchy",
@@ -4910,7 +4910,7 @@ dependencies = [
 [[package]]
 name = "lance-core"
 version = "10.1.0-beta.1"
-source = "git+https://github.com/lance-format/lance.git?rev=b7ef2bae3c7aeb85da637a8c3bc6643ab7d81564#b7ef2bae3c7aeb85da637a8c3bc6643ab7d81564"
+source = "git+https://github.com/lance-format/lance.git?tag=v10.1.0-beta.1#68f4d4c1d0c4871b067557c61fc405078f1ab3b7"
 dependencies = [
  "arrow-array",
  "arrow-buffer",
@@ -4951,7 +4951,7 @@ dependencies = [
 [[package]]
 name = "lance-datafusion"
 version = "10.1.0-beta.1"
-source = "git+https://github.com/lance-format/lance.git?rev=b7ef2bae3c7aeb85da637a8c3bc6643ab7d81564#b7ef2bae3c7aeb85da637a8c3bc6643ab7d81564"
+source = "git+https://github.com/lance-format/lance.git?tag=v10.1.0-beta.1#68f4d4c1d0c4871b067557c61fc405078f1ab3b7"
 dependencies = [
  "arrow",
  "arrow-array",
@@ -4982,7 +4982,7 @@ dependencies = [
 [[package]]
 name = "lance-datagen"
 version = "10.1.0-beta.1"
-source = "git+https://github.com/lance-format/lance.git?rev=b7ef2bae3c7aeb85da637a8c3bc6643ab7d81564#b7ef2bae3c7aeb85da637a8c3bc6643ab7d81564"
+source = "git+https://github.com/lance-format/lance.git?tag=v10.1.0-beta.1#68f4d4c1d0c4871b067557c61fc405078f1ab3b7"
 dependencies = [
  "arrow",
  "arrow-array",
@@ -5000,7 +5000,7 @@ dependencies = [
 [[package]]
 name = "lance-derive"
 version = "10.1.0-beta.1"
-source = "git+https://github.com/lance-format/lance.git?rev=b7ef2bae3c7aeb85da637a8c3bc6643ab7d81564#b7ef2bae3c7aeb85da637a8c3bc6643ab7d81564"
+source = "git+https://github.com/lance-format/lance.git?tag=v10.1.0-beta.1#68f4d4c1d0c4871b067557c61fc405078f1ab3b7"
 dependencies = [
  "proc-macro2",
  "quote",
@@ -5010,7 +5010,7 @@ dependencies = [
 [[package]]
 name = "lance-encoding"
 version = "10.1.0-beta.1"
-source = "git+https://github.com/lance-format/lance.git?rev=b7ef2bae3c7aeb85da637a8c3bc6643ab7d81564#b7ef2bae3c7aeb85da637a8c3bc6643ab7d81564"
+source = "git+https://github.com/lance-format/lance.git?tag=v10.1.0-beta.1#68f4d4c1d0c4871b067557c61fc405078f1ab3b7"
 dependencies = [
  "arrow-arith",
  "arrow-array",
@@ -5046,7 +5046,7 @@ dependencies = [
 [[package]]
 name = "lance-file"
 version = "10.1.0-beta.1"
-source = "git+https://github.com/lance-format/lance.git?rev=b7ef2bae3c7aeb85da637a8c3bc6643ab7d81564#b7ef2bae3c7aeb85da637a8c3bc6643ab7d81564"
+source = "git+https://github.com/lance-format/lance.git?tag=v10.1.0-beta.1#68f4d4c1d0c4871b067557c61fc405078f1ab3b7"
 dependencies = [
  "arrow-arith",
  "arrow-array",
@@ -5078,7 +5078,7 @@ dependencies = [
 [[package]]
 name = "lance-index"
 version = "10.1.0-beta.1"
-source = "git+https://github.com/lance-format/lance.git?rev=b7ef2bae3c7aeb85da637a8c3bc6643ab7d81564#b7ef2bae3c7aeb85da637a8c3bc6643ab7d81564"
+source = "git+https://github.com/lance-format/lance.git?tag=v10.1.0-beta.1#68f4d4c1d0c4871b067557c61fc405078f1ab3b7"
 dependencies = [
  "arc-swap",
  "arrow",
@@ -5146,7 +5146,7 @@ dependencies = [
 [[package]]
 name = "lance-index-core"
 version = "10.1.0-beta.1"
-source = "git+https://github.com/lance-format/lance.git?rev=b7ef2bae3c7aeb85da637a8c3bc6643ab7d81564#b7ef2bae3c7aeb85da637a8c3bc6643ab7d81564"
+source = "git+https://github.com/lance-format/lance.git?tag=v10.1.0-beta.1#68f4d4c1d0c4871b067557c61fc405078f1ab3b7"
 dependencies = [
  "arrow-array",
  "arrow-schema",
@@ -5169,7 +5169,7 @@ dependencies = [
 [[package]]
 name = "lance-io"
 version = "10.1.0-beta.1"
-source = "git+https://github.com/lance-format/lance.git?rev=b7ef2bae3c7aeb85da637a8c3bc6643ab7d81564#b7ef2bae3c7aeb85da637a8c3bc6643ab7d81564"
+source = "git+https://github.com/lance-format/lance.git?tag=v10.1.0-beta.1#68f4d4c1d0c4871b067557c61fc405078f1ab3b7"
 dependencies = [
  "arrow",
  "arrow-array",
@@ -5207,7 +5207,7 @@ dependencies = [
 [[package]]
 name = "lance-linalg"
 version = "10.1.0-beta.1"
-source = "git+https://github.com/lance-format/lance.git?rev=b7ef2bae3c7aeb85da637a8c3bc6643ab7d81564#b7ef2bae3c7aeb85da637a8c3bc6643ab7d81564"
+source = "git+https://github.com/lance-format/lance.git?tag=v10.1.0-beta.1#68f4d4c1d0c4871b067557c61fc405078f1ab3b7"
 dependencies = [
  "arrow-array",
  "arrow-buffer",
@@ -5224,7 +5224,7 @@ dependencies = [
 [[package]]
 name = "lance-namespace"
 version = "10.1.0-beta.1"
-source = "git+https://github.com/lance-format/lance.git?rev=b7ef2bae3c7aeb85da637a8c3bc6643ab7d81564#b7ef2bae3c7aeb85da637a8c3bc6643ab7d81564"
+source = "git+https://github.com/lance-format/lance.git?tag=v10.1.0-beta.1#68f4d4c1d0c4871b067557c61fc405078f1ab3b7"
 dependencies = [
  "arrow",
  "async-trait",
@@ -5237,7 +5237,7 @@ dependencies = [
 [[package]]
 name = "lance-namespace-impls"
 version = "10.1.0-beta.1"
-source = "git+https://github.com/lance-format/lance.git?rev=b7ef2bae3c7aeb85da637a8c3bc6643ab7d81564#b7ef2bae3c7aeb85da637a8c3bc6643ab7d81564"
+source = "git+https://github.com/lance-format/lance.git?tag=v10.1.0-beta.1#68f4d4c1d0c4871b067557c61fc405078f1ab3b7"
 dependencies = [
  "arrow",
  "arrow-ipc",
@@ -5292,7 +5292,7 @@ dependencies = [
 [[package]]
 name = "lance-select"
 version = "10.1.0-beta.1"
-source = "git+https://github.com/lance-format/lance.git?rev=b7ef2bae3c7aeb85da637a8c3bc6643ab7d81564#b7ef2bae3c7aeb85da637a8c3bc6643ab7d81564"
+source = "git+https://github.com/lance-format/lance.git?tag=v10.1.0-beta.1#68f4d4c1d0c4871b067557c61fc405078f1ab3b7"
 dependencies = [
  "arrow-array",
  "arrow-buffer",
@@ -5308,7 +5308,7 @@ dependencies = [
 [[package]]
 name = "lance-table"
 version = "10.1.0-beta.1"
-source = "git+https://github.com/lance-format/lance.git?rev=b7ef2bae3c7aeb85da637a8c3bc6643ab7d81564#b7ef2bae3c7aeb85da637a8c3bc6643ab7d81564"
+source = "git+https://github.com/lance-format/lance.git?tag=v10.1.0-beta.1#68f4d4c1d0c4871b067557c61fc405078f1ab3b7"
 dependencies = [
  "arrow",
  "arrow-array",
@@ -5348,7 +5348,7 @@ dependencies = [
 [[package]]
 name = "lance-testing"
 version = "10.1.0-beta.1"
-source = "git+https://github.com/lance-format/lance.git?rev=b7ef2bae3c7aeb85da637a8c3bc6643ab7d81564#b7ef2bae3c7aeb85da637a8c3bc6643ab7d81564"
+source = "git+https://github.com/lance-format/lance.git?tag=v10.1.0-beta.1#68f4d4c1d0c4871b067557c61fc405078f1ab3b7"
 dependencies = [
  "arrow-array",
  "arrow-schema",
@@ -5362,7 +5362,7 @@ dependencies = [
 [[package]]
 name = "lance-tokenizer"
 version = "10.1.0-beta.1"
-source = "git+https://github.com/lance-format/lance.git?rev=b7ef2bae3c7aeb85da637a8c3bc6643ab7d81564#b7ef2bae3c7aeb85da637a8c3bc6643ab7d81564"
+source = "git+https://github.com/lance-format/lance.git?tag=v10.1.0-beta.1#68f4d4c1d0c4871b067557c61fc405078f1ab3b7"
 dependencies = [
  "icu_segmenter",
  "jieba-rs",
@@ -7583,7 +7583,7 @@ version = "0.14.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "343d3bd7056eda839b03204e68deff7d1b13aba7af2b2fd16890697274262ee7"
 dependencies = [
- "heck 0.5.0",
+ "heck 0.4.1",
  "itertools 0.14.0",
  "log",
  "multimap",
@@ -8498,9 +8498,9 @@ dependencies = [
 
 [[package]]
 name = "rkyv"
-version = "0.8.16"
+version = "0.8.17"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "73389e0c99e664f919275ab5b5b0471391fe9a8de61e1dff9b1eaf56a90f16e3"
+checksum = "815cc8a37159a463064825246cadb07961e25cd9885908606f6d08a98d8f8874"
 dependencies = [
  "bytecheck",
  "bytes",
@@ -8517,9 +8517,9 @@ dependencies = [
 
 [[package]]
 name = "rkyv_derive"
-version = "0.8.16"
+version = "0.8.17"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "5d2ed0b54125315fb36bd021e82d314d1c126548f871634b483f46b31d13cac6"
+checksum = "c0ed1a78a1b19d184b0daa629dd9a024573173ec7d485b287cb369fb3607cc1c"
 dependencies = [
  "proc-macro2",
  "quote",
@@ -9277,7 +9277,7 @@ version = "0.8.9"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "c1c97747dbf44bb1ca44a561ece23508e99cb592e862f22222dcf42f51d1e451"
 dependencies = [
- "heck 0.5.0",
+ "heck 0.4.1",
  "proc-macro2",
  "quote",
  "syn 2.0.117",
@@ -9289,7 +9289,7 @@ version = "0.9.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "54254b8531cafa275c5e096f62d48c81435d1015405a91198ddb11e967301d40"
 dependencies = [
- "heck 0.5.0",
+ "heck 0.4.1",
  "proc-macro2",
  "quote",
  "syn 2.0.117",
@@ -9730,7 +9730,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "32497e9a4c7b38532efcdebeef879707aa9f794296a4f0244f6f69e9bc8574bd"
 dependencies = [
  "fastrand",
- "getrandom 0.4.2",
+ "getrandom 0.3.4",
  "once_cell",
  "rustix",
  "windows-sys 0.61.2",

Cargo.toml

@@ -13,23 +13,20 @@ categories = ["database-implementations"]
 rust-version = "1.91.0"
 
 [workspace.dependencies]
-# TEMPORARY: `ObjectStore::read_dir_stream` is not in a lance release yet, so these point at
-# lance-format/lance#8120 cherry-picked onto the v10.1.0-beta.1 tag. Put the tag back once that
-# PR has merged and shipped in a release.
-lance = { "version" = "=10.1.0-beta.1", default-features = false, "rev" = "b7ef2bae3c7aeb85da637a8c3bc6643ab7d81564", "git" = "https://github.com/lance-format/lance.git" }
-lance-core = { "version" = "=10.1.0-beta.1", "rev" = "b7ef2bae3c7aeb85da637a8c3bc6643ab7d81564", "git" = "https://github.com/lance-format/lance.git" }
-lance-datagen = { "version" = "=10.1.0-beta.1", "rev" = "b7ef2bae3c7aeb85da637a8c3bc6643ab7d81564", "git" = "https://github.com/lance-format/lance.git" }
-lance-file = { "version" = "=10.1.0-beta.1", "rev" = "b7ef2bae3c7aeb85da637a8c3bc6643ab7d81564", "git" = "https://github.com/lance-format/lance.git" }
-lance-io = { "version" = "=10.1.0-beta.1", default-features = false, "rev" = "b7ef2bae3c7aeb85da637a8c3bc6643ab7d81564", "git" = "https://github.com/lance-format/lance.git" }
-lance-index = { "version" = "=10.1.0-beta.1", "rev" = "b7ef2bae3c7aeb85da637a8c3bc6643ab7d81564", "git" = "https://github.com/lance-format/lance.git" }
-lance-linalg = { "version" = "=10.1.0-beta.1", "rev" = "b7ef2bae3c7aeb85da637a8c3bc6643ab7d81564", "git" = "https://github.com/lance-format/lance.git" }
-lance-namespace = { "version" = "=10.1.0-beta.1", "rev" = "b7ef2bae3c7aeb85da637a8c3bc6643ab7d81564", "git" = "https://github.com/lance-format/lance.git" }
-lance-namespace-impls = { "version" = "=10.1.0-beta.1", default-features = false, "rev" = "b7ef2bae3c7aeb85da637a8c3bc6643ab7d81564", "git" = "https://github.com/lance-format/lance.git" }
-lance-table = { "version" = "=10.1.0-beta.1", "rev" = "b7ef2bae3c7aeb85da637a8c3bc6643ab7d81564", "git" = "https://github.com/lance-format/lance.git" }
-lance-testing = { "version" = "=10.1.0-beta.1", "rev" = "b7ef2bae3c7aeb85da637a8c3bc6643ab7d81564", "git" = "https://github.com/lance-format/lance.git" }
-lance-datafusion = { "version" = "=10.1.0-beta.1", "rev" = "b7ef2bae3c7aeb85da637a8c3bc6643ab7d81564", "git" = "https://github.com/lance-format/lance.git" }
-lance-encoding = { "version" = "=10.1.0-beta.1", "rev" = "b7ef2bae3c7aeb85da637a8c3bc6643ab7d81564", "git" = "https://github.com/lance-format/lance.git" }
-lance-arrow = { "version" = "=10.1.0-beta.1", "rev" = "b7ef2bae3c7aeb85da637a8c3bc6643ab7d81564", "git" = "https://github.com/lance-format/lance.git" }
+lance = { "version" = "=10.1.0-beta.1", default-features = false, "tag" = "v10.1.0-beta.1", "git" = "https://github.com/lance-format/lance.git" }
+lance-core = { "version" = "=10.1.0-beta.1", "tag" = "v10.1.0-beta.1", "git" = "https://github.com/lance-format/lance.git" }
+lance-datagen = { "version" = "=10.1.0-beta.1", "tag" = "v10.1.0-beta.1", "git" = "https://github.com/lance-format/lance.git" }
+lance-file = { "version" = "=10.1.0-beta.1", "tag" = "v10.1.0-beta.1", "git" = "https://github.com/lance-format/lance.git" }
+lance-io = { "version" = "=10.1.0-beta.1", default-features = false, "tag" = "v10.1.0-beta.1", "git" = "https://github.com/lance-format/lance.git" }
+lance-index = { "version" = "=10.1.0-beta.1", "tag" = "v10.1.0-beta.1", "git" = "https://github.com/lance-format/lance.git" }
+lance-linalg = { "version" = "=10.1.0-beta.1", "tag" = "v10.1.0-beta.1", "git" = "https://github.com/lance-format/lance.git" }
+lance-namespace = { "version" = "=10.1.0-beta.1", "tag" = "v10.1.0-beta.1", "git" = "https://github.com/lance-format/lance.git" }
+lance-namespace-impls = { "version" = "=10.1.0-beta.1", default-features = false, "tag" = "v10.1.0-beta.1", "git" = "https://github.com/lance-format/lance.git" }
+lance-table = { "version" = "=10.1.0-beta.1", "tag" = "v10.1.0-beta.1", "git" = "https://github.com/lance-format/lance.git" }
+lance-testing = { "version" = "=10.1.0-beta.1", "tag" = "v10.1.0-beta.1", "git" = "https://github.com/lance-format/lance.git" }
+lance-datafusion = { "version" = "=10.1.0-beta.1", "tag" = "v10.1.0-beta.1", "git" = "https://github.com/lance-format/lance.git" }
+lance-encoding = { "version" = "=10.1.0-beta.1", "tag" = "v10.1.0-beta.1", "git" = "https://github.com/lance-format/lance.git" }
+lance-arrow = { "version" = "=10.1.0-beta.1", "tag" = "v10.1.0-beta.1", "git" = "https://github.com/lance-format/lance.git" }
 ahash = "0.8"
 # Note that this one does not include pyarrow
 arrow = { version = "58.0.0", optional = false }

nodejs/src/table.rs

@@ -339,7 +339,9 @@ impl Table {
         let transforms = NewColumnTransform::SqlExpressions(transforms);
         let res = self
             .inner_ref()?
-            .add_columns(transforms, None)
+            .add_columns()
+            .transform(transforms)
+            .execute()
             .await
             .default_error()?;
         Ok(res.into())
@@ -356,7 +358,9 @@ impl Table {
         let transforms = NewColumnTransform::AllNulls(schema);
         let res = self
             .inner_ref()?
-            .add_columns(transforms, None)
+            .add_columns()
+            .transform(transforms)
+            .execute()
             .await
             .default_error()?;
         Ok(res.into())

python/python/lancedb/_lancedb.pyi

@@ -269,6 +269,7 @@ class Table:
         mode: Literal["append", "overwrite"],
         progress: Optional[Any] = None,
         write_parallelism: Optional[int] = None,
+        on_nan_vectors: Optional[Literal["error", "keep"]] = None,
     ) -> AddResult: ...
     async def update(
         self, updates: Dict[str, str], where: Optional[str]

python/python/lancedb/db.py

@@ -333,7 +333,9 @@ class DBConnection(EnforceOverrides):
             schema that's specified.
         on_bad_vectors: str, default "error"
             What to do if any of the vectors are not the same size or contains NaNs.
-            One of "error", "drop", "fill".
+            One of "error", "drop", "fill", "null", or "keep". With "keep",
+            vectors containing NaNs are preserved, but vectors with the wrong
+            dimension still raise an error.
         fill_value: float
             The value to use when filling vectors. Only used if on_bad_vectors="fill".
         storage_options: dict, optional
@@ -707,6 +709,9 @@ class LanceDBConnection(DBConnection):
         self._namespace_client_properties = namespace_client_properties
         if _inner is not None:
             self._conn = _inner
+            # Native-derived wrappers resolve this in their async reconstruction
+            # path so construction never synchronously re-enters LOOP.
+            self._read_consistency_interval = read_consistency_interval
             self._cached_namespace_client = None
             return
 
@@ -756,11 +761,14 @@ class LanceDBConnection(DBConnection):
         # storage_options.  Also, this class really shouldn't be holding any state
         # beyond _conn.
         self._conn = AsyncConnection(LOOP.run(do_connect()))
+        # Keep property access synchronous so debugger introspection cannot wait on
+        # the background loop while that thread is suspended at a breakpoint.
+        self._read_consistency_interval = read_consistency_interval
         self._cached_namespace_client: Optional[LanceNamespace] = None
 
     @property
     def read_consistency_interval(self) -> Optional[timedelta]:
-        return LOOP.run(self._conn.get_read_consistency_interval())
+        return self._read_consistency_interval
 
     @property
     def session(self) -> Optional[Session]:
@@ -771,8 +779,16 @@ class LanceDBConnection(DBConnection):
         return self._conn.uri
 
     @classmethod
-    def from_inner(cls, inner: LanceDbConnection):
-        return cls(None, _inner=inner)
+    def from_inner(
+        cls,
+        inner: LanceDbConnection,
+        read_consistency_interval: Optional[timedelta],
+    ):
+        return cls(
+            None,
+            read_consistency_interval=read_consistency_interval,
+            _inner=inner,
+        )
 
     def __repr__(self) -> str:
         return f"{self.__class__.__name__}(uri={self._conn.uri!r})"
@@ -1581,7 +1597,9 @@ class AsyncConnection(object):
             schema that's specified.
         on_bad_vectors: str, default "error"
             What to do if any of the vectors are not the same size or contains NaNs.
-            One of "error", "drop", "fill".
+            One of "error", "drop", "fill", "null", or "keep". With "keep",
+            vectors containing NaNs are preserved, but vectors with the wrong
+            dimension still raise an error.
         fill_value: float
             The value to use when filling vectors. Only used if on_bad_vectors="fill".
         storage_options: dict, optional

python/python/lancedb/merge.py

@@ -175,7 +175,9 @@ class LanceMergeInsertBuilder(object):
             can be anything you use for [`add`][lancedb.table.Table.add]
         on_bad_vectors: str, default "error"
             What to do if any of the vectors are not the same size or contains NaNs.
-            One of "error", "drop", "fill".
+            One of "error", "drop", "fill", "null", or "keep". With "keep",
+            vectors containing NaNs are preserved, but vectors with the wrong
+            dimension still raise an error.
         fill_value: float, default 0.
             The value to use when filling vectors. Only used if on_bad_vectors="fill".
         timeout: Optional[timedelta], default None

python/python/lancedb/permutation.py

@@ -226,7 +226,7 @@ class PermutationBuilder:
 
         async def do_execute():
             inner_tbl = await self._async.execute()
-            return LanceTable.from_inner(inner_tbl)
+            return await LanceTable.from_inner(inner_tbl)
 
         return LOOP.run(do_execute())
 

python/python/lancedb/remote/db.py

@@ -543,7 +543,9 @@ class RemoteDBConnection(DBConnection):
             to "exist_ok".
         on_bad_vectors: str, default "error"
             What to do if any of the vectors are not the same size or contains NaNs.
-            One of "error", "drop", "fill".
+            One of "error", "drop", "fill", "null", or "keep". With "keep",
+            vectors containing NaNs are preserved, but vectors with the wrong
+            dimension still raise an error.
         fill_value: float
             The value to use when filling vectors. Only used if on_bad_vectors="fill".
 

python/python/lancedb/remote/table.py

@@ -629,7 +629,9 @@ class RemoteTable(Table):
             "append" and "overwrite".
         on_bad_vectors: str, default "error"
             What to do if any of the vectors are not the same size or contains NaNs.
-            One of "error", "drop", "fill".
+            One of "error", "drop", "fill", "null", or "keep". With "keep",
+            vectors containing NaNs are preserved, but vectors with the wrong
+            dimension still raise an error.
         fill_value: float, default 0.
             The value to use when filling vectors. Only used if on_bad_vectors="fill".
         progress: bool, callable, or tqdm-like, optional

python/python/lancedb/table.py

@@ -350,8 +350,10 @@ def _sanitize_data(
         in the input table before casting.
     metadata : Optional[dict], default None
         The embedding metadata to add to the schema.
-    on_bad_vectors : Literal["error", "drop", "fill", "null"], default "error"
+    on_bad_vectors : Literal["error", "drop", "fill", "null", "keep"], default "error"
         What to do if any of the vectors are not the same size or contains NaNs.
+        With "keep", vectors containing NaNs are preserved, but vectors with the
+        wrong dimension still raise an error.
     fill_value : float, default 0.0
         The value to use when filling vectors. Only used if on_bad_vectors="fill".
         All entries in the vector will be set to this value.
@@ -1247,7 +1249,9 @@ class Table(ABC):
             "append" and "overwrite".
         on_bad_vectors: str, default "error"
             What to do if any of the vectors are not the same size or contains NaNs.
-            One of "error", "drop", "fill".
+            One of "error", "drop", "fill", "null", or "keep". With "keep",
+            vectors containing NaNs are preserved but are not indexed for vector
+            search; vectors with the wrong dimension still raise an error.
         fill_value: float, default 0.
             The value to use when filling vectors. Only used if on_bad_vectors="fill".
         progress: bool, callable, or tqdm-like, optional
@@ -2182,11 +2186,15 @@ class LanceTable(Table):
         return self.name
 
     @classmethod
-    def from_inner(cls, tbl: LanceDBTable):
-        from .db import LanceDBConnection
+    async def from_inner(cls, tbl: LanceDBTable):
+        from .db import AsyncConnection, LanceDBConnection
 
         async_tbl = AsyncTable(tbl)
-        conn = LanceDBConnection.from_inner(tbl.database())
+        inner_conn = tbl.database()
+        read_consistency_interval = await AsyncConnection(
+            inner_conn
+        ).get_read_consistency_interval()
+        conn = LanceDBConnection.from_inner(inner_conn, read_consistency_interval)
         return cls(
             conn,
             async_tbl.name,
@@ -3265,7 +3273,9 @@ class LanceTable(Table):
             "append" and "overwrite".
         on_bad_vectors: str, default "error"
             What to do if any of the vectors are not the same size or contains NaNs.
-            One of "error", "drop", "fill", "null".
+            One of "error", "drop", "fill", "null", or "keep". With "keep",
+            vectors containing NaNs are preserved, but vectors with the wrong
+            dimension still raise an error.
         fill_value: float, default 0.
             The value to use when filling vectors. Only used if on_bad_vectors="fill".
         progress: bool, callable, or tqdm-like, optional
@@ -3578,7 +3588,9 @@ class LanceTable(Table):
             data but will validate against any schema that's specified.
         on_bad_vectors: str, default "error"
             What to do if any of the vectors are not the same size or contains NaNs.
-            One of "error", "drop", "fill", "null".
+            One of "error", "drop", "fill", "null", or "keep". With "keep",
+            vectors containing NaNs are preserved, but vectors with the wrong
+            dimension still raise an error.
         fill_value: float, default 0.
             The value to use when filling vectors. Only used if on_bad_vectors="fill".
         embedding_functions: list of EmbeddingFunctionModel, default None
@@ -4014,7 +4026,7 @@ class LanceTable(Table):
 
 def _handle_bad_vectors(
     reader: pa.RecordBatchReader,
-    on_bad_vectors: Literal["error", "drop", "fill", "null"] = "error",
+    on_bad_vectors: OnBadVectorsType = "error",
     fill_value: float = 0.0,
     target_schema: Optional[pa.Schema] = None,
     metadata: Optional[dict] = None,
@@ -4188,7 +4200,9 @@ def _handle_bad_vector_column(
         The name of the vector column.
     on_bad_vectors: str, default "error"
         What to do if any of the vectors are not the same size or contains NaNs.
-        One of "error", "drop", "fill", "null".
+        One of "error", "drop", "fill", "null", or "keep". With "keep",
+        vectors containing NaNs are preserved, but vectors with the wrong dimension
+        still raise an error.
     fill_value: float, default 0.0
         The value to use when filling vectors. Only used if on_bad_vectors="fill".
     """
@@ -4253,7 +4267,8 @@ def _handle_bad_vector_column(
                     f"Vector column '{vector_column_name}' has NaNs. "
                     "Set on_bad_vectors='drop' to remove them, "
                     "set on_bad_vectors='fill' and fill_value=<value> to replace them, "
-                    "or set on_bad_vectors='null' to replace them with null."
+                    "set on_bad_vectors='null' to replace them with null, "
+                    "or set on_bad_vectors='keep' to preserve them."
                 )
         elif on_bad_vectors == "null":
             vec_arr = pc.if_else(
@@ -4270,6 +4285,16 @@ def _handle_bad_vector_column(
                     "`fill_value` must not be None if `on_bad_vectors` is 'fill'"
                 )
             vec_arr = _fill_bad_vector_values(vec_arr, dim, fill_value)
+        elif on_bad_vectors == "keep":
+            if pc.any(has_wrong_dim).as_py():
+                raise ValueError(
+                    f"Vector column '{vector_column_name}' has variable length "
+                    "vectors. on_bad_vectors='keep' only preserves vectors "
+                    "containing NaNs. Set on_bad_vectors='drop' to remove "
+                    "wrong-size vectors, set on_bad_vectors='fill' and "
+                    "fill_value=<value> to replace them, or set "
+                    "on_bad_vectors='null' to replace them with null."
+                )
         else:
             raise ValueError(f"Invalid value for on_bad_vectors: {on_bad_vectors}")
 
@@ -5114,7 +5139,9 @@ class AsyncTable:
             "append" and "overwrite".
         on_bad_vectors: str, default "error"
             What to do if any of the vectors are not the same size or contains NaNs.
-            One of "error", "drop", "fill", "null".
+            One of "error", "drop", "fill", "null", or "keep". With "keep",
+            vectors containing NaNs are preserved but are not indexed for vector
+            search; vectors with the wrong dimension still raise an error.
         fill_value: float, default 0.
             The value to use when filling vectors. Only used if on_bad_vectors="fill".
         progress: callable or tqdm-like, optional
@@ -5162,6 +5189,7 @@ class AsyncTable:
                 mode or "append",
                 progress=progress,
                 write_parallelism=write_parallelism,
+                on_nan_vectors="keep" if on_bad_vectors == "keep" else None,
             )
         except RuntimeError as e:
             if "Cast error" in str(e):

python/python/lancedb/types.py

@@ -24,7 +24,7 @@ DistanceType = Literal["l2", "cosine", "dot"]
 DistanceTypeWithHamming = Literal["l2", "cosine", "dot", "hamming"]
 
 # Vector handling literals
-OnBadVectorsType = Literal["error", "drop", "fill", "null"]
+OnBadVectorsType = Literal["error", "drop", "fill", "null", "keep"]
 
 # Mode literals
 AddMode = Literal["append", "overwrite"]

python/python/tests/test_db.py

@@ -77,6 +77,23 @@ def test_sync_repr_does_not_use_background_loop(tmp_path, monkeypatch):
     assert repr(table) == f"LanceTable(name='test', _conn={db!r})"
 
 
+def test_read_consistency_interval_does_not_use_background_loop(tmp_path, monkeypatch):
+    from lancedb.background_loop import LOOP
+    from lancedb.db import LanceDBConnection
+
+    consistency_interval = timedelta(seconds=5)
+    db = lancedb.connect(tmp_path, read_consistency_interval=consistency_interval)
+    db_from_inner = LanceDBConnection.from_inner(db._inner, consistency_interval)
+
+    def fail_run(*args, **kwargs):
+        raise AssertionError("properties should not use the Python background loop")
+
+    monkeypatch.setattr(LOOP, "run", fail_run)
+
+    assert db.read_consistency_interval == consistency_interval
+    assert db_from_inner.read_consistency_interval == consistency_interval
+
+
 def test_ingest_pd(tmp_path):
     db = lancedb.connect(tmp_path)
 

python/python/tests/test_permutation.py

@@ -6,6 +6,7 @@ import math
 import pytest
 
 from lancedb import DBConnection, Table, connect
+from lancedb.background_loop import LOOP
 from lancedb.permutation import Permutation, Permutations, permutation_builder
 
 
@@ -31,6 +32,25 @@ def test_split_random_ratios(mem_db):
     assert 65 <= split_1_count <= 75  # ~70% ± tolerance
 
 
+def test_execute_does_not_reenter_background_loop(tmp_path, monkeypatch):
+    import threading
+
+    db = connect(tmp_path)
+    tbl = db.create_table("test_table", pa.table({"x": range(10)}))
+    original_run = LOOP.run
+
+    def fail_on_reentry(future):
+        assert threading.current_thread() is not LOOP.thread
+        return original_run(future)
+
+    monkeypatch.setattr(LOOP, "run", fail_on_reentry)
+
+    permutation_tbl = permutation_builder(tbl).execute()
+
+    assert permutation_tbl.count_rows() == 10
+    assert permutation_tbl._conn.read_consistency_interval is None
+
+
 def test_split_random_counts(mem_db):
     """Test random splitting with absolute counts."""
     tbl = mem_db.create_table(

python/python/tests/test_table.py

@@ -6,6 +6,7 @@ import os
 import sys
 import threading
 import warnings
+from concurrent.futures import ThreadPoolExecutor
 from datetime import date, datetime, timedelta
 from time import sleep
 from typing import List
@@ -1766,6 +1767,40 @@ def test_add_with_nans(mem_db: DBConnection):
     assert np.allclose(filled_vectors[22.0], np.array([5.0, 0.0]))
 
 
+def test_add_with_non_finite_values_keep(mem_db: DBConnection):
+    schema = pa.schema([pa.field("data", pa.list_(pa.float32(), 4))])
+    table = mem_db.create_table("test", schema=schema)
+    batch = pa.table(
+        {
+            "data": pa.array(
+                [[np.nan, np.inf, -np.inf, -0.0]],
+                type=schema.field("data").type,
+            )
+        },
+        schema=schema,
+    )
+
+    with pytest.raises(ValueError, match="NaN"):
+        table.add(batch)
+
+    table.add(batch, on_bad_vectors="keep")
+
+    values = table.to_arrow()["data"][0].as_py()
+    assert np.isnan(values[0])
+    assert np.isposinf(values[1])
+    assert np.isneginf(values[2])
+    assert values[3] == 0.0
+    assert np.signbit(values[3])
+
+
+def test_add_keep_rejects_wrong_dimension(mem_db: DBConnection):
+    schema = pa.schema([pa.field("vector", pa.list_(pa.float32(), 2))])
+    table = mem_db.create_table("test", schema=schema)
+
+    with pytest.raises((ValueError, RuntimeError), match="variable length"):
+        table.add([{"vector": [1.0]}], on_bad_vectors="keep")
+
+
 def test_add_with_empty_fixed_size_list_drops_bad_rows(mem_db: DBConnection):
     class Schema(LanceModel):
         text: str
@@ -2124,6 +2159,27 @@ def test_delete(mem_db: DBConnection):
     assert table.to_arrow()["id"].to_pylist() == [1]
 
 
+def test_concurrent_deletes_are_thread_safe(mem_db: DBConnection):
+    num_workers = 8
+    table = mem_db.create_table(
+        "my_table", data=[{"id": row_id} for row_id in range(num_workers)]
+    )
+    barrier = threading.Barrier(num_workers)
+
+    def delete(row_id: int):
+        barrier.wait()
+        return table.delete(f"id = {row_id}")
+
+    with ThreadPoolExecutor(max_workers=num_workers) as pool:
+        results = list(pool.map(delete, range(num_workers)))
+
+    assert all(result.num_deleted_rows == 1 for result in results)
+    assert sorted(result.version for result in results) == list(
+        range(2, num_workers + 2)
+    )
+    assert table.count_rows() == 0
+
+
 def test_delete_expr(mem_db: DBConnection):
     table = mem_db.create_table(
         "my_table",

python/python/tests/test_util.py

@@ -2,6 +2,7 @@
 # SPDX-FileCopyrightText: Copyright The LanceDB Authors
 
 
+import math
 import os
 import pathlib
 from typing import Optional
@@ -364,7 +365,7 @@ def test_fill_bad_vector_values_arrow_types(vector_type, vectors, expected):
     assert actual.to_pylist() == expected
 
 
-@pytest.mark.parametrize("on_bad_vectors", ["error", "drop", "fill", "null"])
+@pytest.mark.parametrize("on_bad_vectors", ["error", "drop", "fill", "null", "keep"])
 def test_handle_bad_vectors_nan(on_bad_vectors):
     vector = pa.array([[1.0, float("nan")], [3.0, 4.0]])
     data = pa.table({"vector": vector})
@@ -379,8 +380,9 @@ def test_handle_bad_vectors_nan(on_bad_vectors):
         assert output == (
             "ValueError: Vector column 'vector' has NaNs. Set "
             "on_bad_vectors='drop' to remove them, set on_bad_vectors='fill' "
-            "and fill_value=<value> to replace them, or set on_bad_vectors='null' "
-            "to replace them with null."
+            "and fill_value=<value> to replace them, set on_bad_vectors='null' "
+            "to replace them with null, or set on_bad_vectors='keep' to preserve "
+            "them."
         )
         return
     else:
@@ -396,10 +398,26 @@ def test_handle_bad_vectors_nan(on_bad_vectors):
         expected = pa.array([[1.0, 42.0], [3.0, 4.0]])
     elif on_bad_vectors == "null":
         expected = pa.array([None, [3.0, 4.0]])
+    elif on_bad_vectors == "keep":
+        actual = output["vector"].to_pylist()
+        assert actual[0][0] == 1.0
+        assert math.isnan(actual[0][1])
+        assert actual[1] == [3.0, 4.0]
+        return
 
     assert output["vector"].combine_chunks() == expected
 
 
+def test_handle_bad_vectors_keep_rejects_wrong_dimension():
+    data = pa.table({"vector": [[1.0, 2.0], [3.0]]})
+
+    with pytest.raises(ValueError, match="only preserves vectors containing NaNs"):
+        _handle_bad_vectors(
+            data.to_reader(),
+            on_bad_vectors="keep",
+        ).read_all()
+
+
 def test_handle_bad_vectors_noop():
     # ChunkedArray should be preserved as-is
     vector = pa.chunked_array(

python/src/table.rs

@@ -21,7 +21,8 @@ use lancedb::blob::{BlobFile, BlobRangeRequest};
 use lancedb::index::scalar::FtsIndexBuilder;
 use lancedb::table::{
     AddDataMode, ColumnAlteration, Duration, FieldMetadataUpdate, FtsToken as LanceDbFtsToken,
-    NewColumnTransform, OptimizeAction, OptimizeOptions, Ref, Table as LanceDbTable,
+    NaNVectorBehavior, NewColumnTransform, OptimizeAction, OptimizeOptions, Ref,
+    Table as LanceDbTable,
 };
 use lancedb::tokenize as lancedb_tokenize;
 use pyo3::{
@@ -642,13 +643,14 @@ impl Table {
         })
     }
 
-    #[pyo3(signature = (data, mode, progress=None, write_parallelism=None))]
+    #[pyo3(signature = (data, mode, progress=None, write_parallelism=None, on_nan_vectors=None))]
     pub fn add<'a>(
         self_: PyRef<'a, Self>,
         data: PyScannable,
         mode: String,
         progress: Option<Py<PyAny>>,
         write_parallelism: Option<usize>,
+        on_nan_vectors: Option<String>,
     ) -> PyResult<Bound<'a, PyAny>> {
         let mut op = self_.inner_ref()?.add(data);
         if mode == "append" {
@@ -658,6 +660,18 @@ impl Table {
         } else {
             return Err(PyValueError::new_err(format!("Invalid mode: {}", mode)));
         }
+        match on_nan_vectors.as_deref() {
+            None | Some("error") => {}
+            Some("keep") => {
+                op = op.on_nan_vectors(NaNVectorBehavior::Keep);
+            }
+            Some(other) => {
+                return Err(PyValueError::new_err(format!(
+                    "Invalid on_nan_vectors: {}",
+                    other
+                )));
+            }
+        }
         if let Some(write_parallelism) = write_parallelism {
             op = op.write_parallelism(write_parallelism);
         }
@@ -745,6 +759,9 @@ impl Table {
 
     #[allow(private_interfaces)]
     pub fn delete(self_: PyRef<'_, Self>, condition: PredicateArg) -> PyResult<Bound<'_, PyAny>> {
+        // Do not hold the Python borrow across the await.  The cloned Rust table
+        // handle is thread-safe and allows deletes on the same Python table to
+        // run concurrently without PyO3 reporting "Already borrowed".
         let inner = self_.inner_ref()?.clone();
         future_into_py(self_.py(), async move {
             let result = match &condition {
@@ -1375,7 +1392,12 @@ impl Table {
 
         let inner = self_.inner_ref()?.clone();
         future_into_py(self_.py(), async move {
-            let result = inner.add_columns(definitions, None).await.infer_error()?;
+            let result = inner
+                .add_columns()
+                .transform(definitions)
+                .execute()
+                .await
+                .infer_error()?;
             Ok(AddColumnsResult::from(result))
         })
     }
@@ -1389,7 +1411,12 @@ impl Table {
 
         let inner = self_.inner_ref()?.clone();
         future_into_py(self_.py(), async move {
-            let result = inner.add_columns(transform, None).await.infer_error()?;
+            let result = inner
+                .add_columns()
+                .transform(transform)
+                .execute()
+                .await
+                .infer_error()?;
             Ok(AddColumnsResult::from(result))
         })
     }

rust/lancedb/src/database/listing.rs

@@ -8,15 +8,12 @@ use std::fs::create_dir_all;
 use std::path::Path;
 use std::{collections::HashMap, sync::Arc};
 
-use futures::TryStreamExt;
 use lance::dataset::refs::Ref;
 use lance::dataset::{ReadParams, WriteMode, builder::DatasetBuilder};
 use lance::io::{ObjectStore, ObjectStoreParams, WrappingObjectStore};
 use lance_datafusion::utils::StreamingWriteSource;
 use lance_encoding::version::LanceFileVersion;
-use lance_io::object_store::{
-    DirCursor, ReadDirOptions, StorageOptionsAccessor, StorageOptionsProvider,
-};
+use lance_io::object_store::{StorageOptionsAccessor, StorageOptionsProvider};
 use lance_table::io::commit::commit_handler_from_url;
 use object_store::local::LocalFileSystem;
 use snafu::ResultExt;
@@ -721,54 +718,6 @@ impl ListingDatabase {
         self.namespace_database.clone()
     }
 
-    /// List up to `limit` table names, resuming after the table named `start_after`.
-    ///
-    /// The cursor and the page size go into the object store's list request rather than
-    /// being applied to a full listing, so the cost of a page is set by the size of the
-    /// page and not by the size of the database. Stores with no paginated list API fall
-    /// back to a full listing, which is what this did for every store before.
-    ///
-    /// Names come back in the order the store lists the directories in, which is by key:
-    /// `foo-bar` precedes `foo`, because the `-` of `foo-bar.lance` sorts below the `.` of
-    /// `foo.lance`. Pagination has to follow the order the cursor is pushed down in, so
-    /// that is the order both listing methods report and the order `start_after` resumes
-    /// in. It matches sorting by name except between a name and one that extends it.
-    async fn list_table_dirs(
-        &self,
-        start_after: Option<&str>,
-        limit: Option<usize>,
-    ) -> Result<Vec<String>> {
-        let dir_suffix = format!(".{}", LANCE_EXTENSION);
-        let options = ReadDirOptions {
-            // An empty name means "from the start": that is how comparing names against it
-            // behaved, and how a client looping on a page token spells its first request.
-            // Built into a cursor it would instead sit after every name below `.lance`.
-            resume_from: start_after
-                .filter(|name| !name.is_empty())
-                .map(|name| DirCursor::after_directory(format!("{name}{dir_suffix}"))),
-            page_size: limit,
-        };
-        let mut entries = self
-            .object_store
-            .read_dir_stream(self.base_path.clone(), options);
-
-        let mut names = Vec::new();
-        while limit.is_none_or(|limit| names.len() < limit) {
-            let Some(entry) = entries.try_next().await? else {
-                break;
-            };
-            // A table is the directory `<name>.lance`; anything else under the database
-            // prefix belongs to something other than a table.
-            if !entry.is_dir() {
-                continue;
-            }
-            if let Some(name) = entry.name.strip_suffix(&dir_suffix) {
-                names.push(name.to_string());
-            }
-        }
-        Ok(names)
-    }
-
     async fn drop_tables(&self, names: Vec<String>) -> Result<()> {
         let object_store_params = ObjectStoreParams {
             storage_options_accessor: if self.storage_options.is_empty() {
@@ -1010,37 +959,80 @@ impl Database for ListingDatabase {
         if !request.namespace_path.is_empty() {
             return self.namespace_database().table_names(request).await;
         }
-        self.list_table_dirs(
-            request.start_after.as_deref(),
-            request.limit.map(|limit| limit as usize),
-        )
-        .await
+        let mut f = self
+            .object_store
+            .read_dir(self.base_path.clone())
+            .await?
+            .iter()
+            .map(Path::new)
+            .filter(|path| {
+                let is_lance = path
+                    .extension()
+                    .and_then(|e| e.to_str())
+                    .map(|e| e == LANCE_EXTENSION);
+                is_lance.unwrap_or(false)
+            })
+            .filter_map(|p| p.file_stem().and_then(|s| s.to_str().map(String::from)))
+            .collect::<Vec<String>>();
+        f.sort();
+        if let Some(start_after) = request.start_after {
+            let index = f
+                .iter()
+                .position(|name| name.as_str() > start_after.as_str())
+                .unwrap_or(f.len());
+            f.drain(0..index);
+        }
+        if let Some(limit) = request.limit {
+            f.truncate(limit as usize);
+        }
+        Ok(f)
     }
 
     async fn list_tables(&self, request: ListTablesRequest) -> Result<ListTablesResponse> {
         if request.id.as_ref().map(|v| !v.is_empty()).unwrap_or(false) {
             return self.namespace_database().list_tables(request).await;
         }
-        let limit = request.limit.map(|limit| limit as usize);
-        // Reading one past the page is how we learn whether another page follows, without
-        // a second request. The extra name is dropped before the response goes out.
-        let mut tables = self
-            .list_table_dirs(
-                request.page_token.as_deref(),
-                limit.map(|limit| limit.saturating_add(1)),
-            )
-            .await?;
+        let mut f = self
+            .object_store
+            .read_dir(self.base_path.clone())
+            .await?
+            .iter()
+            .map(Path::new)
+            .filter(|path| {
+                let is_lance = path
+                    .extension()
+                    .and_then(|e| e.to_str())
+                    .map(|e| e == LANCE_EXTENSION);
+                is_lance.unwrap_or(false)
+            })
+            .filter_map(|p| p.file_stem().and_then(|s| s.to_str().map(String::from)))
+            .collect::<Vec<String>>();
+        f.sort();
 
-        let next_page_token = match limit {
-            Some(limit) if tables.len() > limit => {
-                tables.truncate(limit);
-                tables.last().cloned()
+        // Handle pagination with page_token
+        if let Some(ref page_token) = request.page_token {
+            let index = f
+                .iter()
+                .position(|name| name.as_str() > page_token.as_str())
+                .unwrap_or(f.len());
+            f.drain(0..index);
+        }
+
+        // Determine if there's a next page
+        let next_page_token = if let Some(limit) = request.limit {
+            if f.len() > limit as usize {
+                let token = f[limit as usize].clone();
+                f.truncate(limit as usize);
+                Some(token)
+            } else {
+                None
             }
-            _ => None,
+        } else {
+            None
         };
 
         Ok(ListTablesResponse {
-            tables,
+            tables: f,
             page_token: next_page_token,
         })
     }
@@ -1330,130 +1322,6 @@ mod tests {
         (tempdir, db)
     }
 
-    async fn create_tables(db: &ListingDatabase, names: &[&str]) {
-        let schema = Arc::new(Schema::new(vec![Field::new("id", DataType::Int32, false)]));
-        for name in names {
-            db.create_table(CreateTableRequest {
-                name: name.to_string(),
-                namespace_path: vec![],
-                data: Box::new(RecordBatch::new_empty(schema.clone())) as Box<dyn Scannable>,
-                mode: CreateTableMode::Create,
-                write_options: Default::default(),
-                location: None,
-                namespace_client: None,
-            })
-            .await
-            .unwrap();
-        }
-    }
-
-    /// Paging with the returned token has to visit every table exactly once. The token is
-    /// the last name of the page, which is what `page_token` resumes after.
-    #[tokio::test]
-    async fn test_list_tables_pages_over_every_table_once() {
-        let (_tempdir, db) = setup_database().await;
-        create_tables(&db, &["a", "b", "c", "d", "e"]).await;
-
-        let mut seen = Vec::new();
-        let mut page_token = None;
-        loop {
-            let page = db
-                .list_tables(ListTablesRequest {
-                    limit: Some(2),
-                    page_token,
-                    ..Default::default()
-                })
-                .await
-                .unwrap();
-            seen.extend(page.tables);
-            match page.page_token {
-                Some(token) => page_token = Some(token),
-                None => break,
-            }
-        }
-
-        assert_eq!(seen, vec!["a", "b", "c", "d", "e"]);
-    }
-
-    /// The last page reports no token, so a caller paging by token knows to stop without
-    /// asking for an empty page.
-    #[tokio::test]
-    async fn test_list_tables_exhausted_page_has_no_token() {
-        let (_tempdir, db) = setup_database().await;
-        create_tables(&db, &["a", "b"]).await;
-
-        let page = db
-            .list_tables(ListTablesRequest {
-                limit: Some(2),
-                ..Default::default()
-            })
-            .await
-            .unwrap();
-
-        assert_eq!(page.tables, vec!["a", "b"]);
-        assert_eq!(page.page_token, None);
-    }
-
-    /// Listing follows the order the object store lists directories in, so a name that
-    /// extends another comes first: `-` sorts below the `.` of `.lance`. Pagination pushes
-    /// its cursor into the list request, so it cannot report a different order than the
-    /// one it resumes in.
-    #[tokio::test]
-    async fn test_listing_order_follows_the_store_not_the_table_name() {
-        let (_tempdir, db) = setup_database().await;
-        create_tables(&db, &["users", "users-archive", "users.old"]).await;
-
-        #[allow(deprecated)]
-        let names = db.table_names(TableNamesRequest::default()).await.unwrap();
-        assert_eq!(names, vec!["users-archive", "users", "users.old"]);
-
-        // Resuming after a name skips everything the store lists before it, which is what
-        // paging by the previous page's last name relies on.
-        #[allow(deprecated)]
-        let after = db
-            .table_names(TableNamesRequest {
-                start_after: Some("users-archive".to_string()),
-                ..Default::default()
-            })
-            .await
-            .unwrap();
-        assert_eq!(after, vec!["users", "users.old"]);
-    }
-
-    /// An empty `start_after` means "from the start". A name that sorts below `.lance` is
-    /// what disappears if it is treated as a cursor instead.
-    #[tokio::test]
-    async fn test_empty_start_after_lists_from_the_start() {
-        let (_tempdir, db) = setup_database().await;
-        create_tables(&db, &["-dash", "alpha"]).await;
-
-        #[allow(deprecated)]
-        let names = db
-            .table_names(TableNamesRequest {
-                start_after: Some(String::new()),
-                ..Default::default()
-            })
-            .await
-            .unwrap();
-
-        assert_eq!(names, vec!["-dash", "alpha"]);
-    }
-
-    /// Only directories named `<name>.lance` are tables; loose files and other directories
-    /// under the database prefix are not.
-    #[tokio::test]
-    async fn test_listing_ignores_non_table_children() {
-        let (tempdir, db) = setup_database().await;
-        create_tables(&db, &["real"]).await;
-        std::fs::write(tempdir.path().join("loose.lance"), b"not a table").unwrap();
-        create_dir_all(tempdir.path().join("scratch")).unwrap();
-
-        #[allow(deprecated)]
-        let names = db.table_names(TableNamesRequest::default()).await.unwrap();
-
-        assert_eq!(names, vec!["real"]);
-    }
-
     #[tokio::test]
     async fn test_listing_database_root_ops_do_not_create_manifest() {
         let tempdir = tempdir().unwrap();

rust/lancedb/src/remote/table.rs

@@ -3089,10 +3089,12 @@ mod tests {
             Box::pin(table.delete("false").map_ok(|_| ())),
             Box::pin(
                 table
-                    .add_columns(
-                        NewColumnTransform::SqlExpressions(vec![("x".into(), "y".into())]),
-                        None,
-                    )
+                    .add_columns()
+                    .transform(NewColumnTransform::SqlExpressions(vec![(
+                        "x".into(),
+                        "y".into(),
+                    )]))
+                    .execute()
                     .map_ok(|_| ()),
             ),
             Box::pin(async {
@@ -6388,13 +6390,12 @@ mod tests {
         });
 
         let result = table
-            .add_columns(
-                NewColumnTransform::SqlExpressions(vec![
-                    ("b".into(), "a + 1".into()),
-                    ("x".into(), "cast(NULL as int32)".into()),
-                ]),
-                None,
-            )
+            .add_columns()
+            .transform(NewColumnTransform::SqlExpressions(vec![
+                ("b".into(), "a + 1".into()),
+                ("x".into(), "cast(NULL as int32)".into()),
+            ]))
+            .execute()
             .await
             .unwrap();
 
@@ -7119,10 +7120,12 @@ mod tests {
             }
             "add_columns" => {
                 let _ = table
-                    .add_columns(
-                        NewColumnTransform::SqlExpressions(vec![("c".into(), "a + 1".into())]),
-                        None,
-                    )
+                    .add_columns()
+                    .transform(NewColumnTransform::SqlExpressions(vec![(
+                        "c".into(),
+                        "a + 1".into(),
+                    )]))
+                    .execute()
                     .await;
             }
             "drop_columns" => {
@@ -9880,10 +9883,12 @@ mod tests {
             .await
             .unwrap();
         branch
-            .add_columns(
-                NewColumnTransform::SqlExpressions(vec![("b".into(), "a + 1".into())]),
-                None,
-            )
+            .add_columns()
+            .transform(NewColumnTransform::SqlExpressions(vec![(
+                "b".into(),
+                "a + 1".into(),
+            )]))
+            .execute()
             .await
             .unwrap();
         branch

rust/lancedb/src/table.rs

@@ -65,6 +65,7 @@ use crate::utils::{PatchReadParam, PatchWriteParam, resolve_arrow_field_path};
 use self::dataset::DatasetConsistencyWrapper;
 use self::merge::MergeInsertBuilder;
 
+pub mod add_columns;
 mod add_data;
 pub mod branch_merge;
 mod create_index;
@@ -79,6 +80,7 @@ pub mod schema_evolution;
 pub mod update;
 pub mod write_progress;
 use crate::index::waiter::wait_for_index;
+pub use add_columns::AddColumnsBuilder;
 #[cfg(feature = "remote")]
 pub(crate) use add_data::PreprocessingOutput;
 pub use add_data::{AddDataBuilder, AddDataMode, AddResult, NaNVectorBehavior};
@@ -1620,12 +1622,8 @@ impl Table {
     }
 
     /// Add new columns to the table, providing values to fill in.
-    pub async fn add_columns(
-        &self,
-        transforms: NewColumnTransform,
-        read_columns: Option<Vec<String>>,
-    ) -> Result<AddColumnsResult> {
-        self.inner.add_columns(transforms, read_columns).await
+    pub fn add_columns(&self) -> AddColumnsBuilder {
+        AddColumnsBuilder::new(self.inner.clone())
     }
 
     /// Change a column's name or nullability.

rust/lancedb/src/table/add_columns.rs

@@ -0,0 +1,161 @@
+// SPDX-License-Identifier: Apache-2.0
+// SPDX-FileCopyrightText: Copyright The LanceDB Authors
+
+//! Builder for adding columns to a table.
+
+use std::sync::Arc;
+
+use lance::dataset::NewColumnTransform;
+
+use super::BaseTable;
+use super::schema_evolution::AddColumnsResult;
+use crate::{Error, Result};
+
+/// Adds columns to a table. See [`Table::add_columns`](super::Table::add_columns).
+pub struct AddColumnsBuilder {
+    parent: Arc<dyn BaseTable>,
+    transform: Option<NewColumnTransform>,
+    read_columns: Option<Vec<String>>,
+}
+
+impl std::fmt::Debug for AddColumnsBuilder {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        f.debug_struct("AddColumnsBuilder")
+            .field("parent", &self.parent)
+            .field("has_transform", &self.transform.is_some())
+            .field("read_columns", &self.read_columns)
+            .finish()
+    }
+}
+
+impl AddColumnsBuilder {
+    pub(crate) fn new(parent: Arc<dyn BaseTable>) -> Self {
+        Self {
+            parent,
+            transform: None,
+            read_columns: None,
+        }
+    }
+
+    /// Set how the new columns' values are produced. Required.
+    pub fn transform(mut self, transform: NewColumnTransform) -> Self {
+        self.transform = Some(transform);
+        self
+    }
+
+    /// Limit which existing columns a [`NewColumnTransform::BatchUDF`] mapper
+    /// receives. Every other transform determines what it reads, so setting
+    /// this alongside one is an error rather than a silent no-op.
+    pub fn read_columns(mut self, columns: impl IntoIterator<Item = impl Into<String>>) -> Self {
+        self.read_columns = Some(columns.into_iter().map(Into::into).collect());
+        self
+    }
+
+    /// Add the columns.
+    pub async fn execute(self) -> Result<AddColumnsResult> {
+        let Self {
+            parent,
+            transform,
+            read_columns,
+        } = self;
+
+        let Some(transform) = transform else {
+            return Err(Error::InvalidInput {
+                message: "add_columns requires a transform".into(),
+            });
+        };
+
+        if read_columns.is_some() && !matches!(transform, NewColumnTransform::BatchUDF(_)) {
+            return Err(Error::InvalidInput {
+                message: "read_columns applies only to a BatchUDF transform; \
+                          every other transform determines what it reads"
+                    .into(),
+            });
+        }
+
+        parent.add_columns(transform, read_columns).await
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use std::sync::Arc;
+
+    use arrow_array::{Int32Array, RecordBatch, record_batch};
+    use arrow_schema::{DataType, Field, Schema};
+    use lance::dataset::{BatchUDF, NewColumnTransform};
+
+    use crate::Table;
+    use crate::connect;
+
+    async fn table_with_two_columns(name: &str) -> Table {
+        let conn = connect("memory://").execute().await.unwrap();
+        let batch = record_batch!(("x", Int32, [1, 2, 3]), ("y", Int32, [10, 20, 30])).unwrap();
+        conn.create_table(name, batch).execute().await.unwrap()
+    }
+
+    #[tokio::test]
+    async fn test_requires_a_transform() {
+        let table = table_with_two_columns("no_transform").await;
+        let err = table.add_columns().execute().await.unwrap_err();
+        assert!(
+            err.to_string().contains("requires a transform"),
+            "got: {err}"
+        );
+    }
+
+    #[tokio::test]
+    async fn test_read_columns_with_sql_expressions_is_rejected() {
+        let table = table_with_two_columns("read_cols_sql").await;
+        let err = table
+            .add_columns()
+            .transform(NewColumnTransform::SqlExpressions(vec![(
+                "doubled".into(),
+                "x * 2".into(),
+            )]))
+            .read_columns(["x"])
+            .execute()
+            .await
+            .unwrap_err();
+        assert!(err.to_string().contains("BatchUDF"), "got: {err}");
+
+        let schema = table.schema().await.unwrap();
+        assert!(
+            schema.field_with_name("doubled").is_err(),
+            "a rejected call must not commit"
+        );
+    }
+
+    #[tokio::test]
+    async fn test_read_columns_limits_what_a_batch_udf_sees() {
+        let table = table_with_two_columns("read_cols_udf").await;
+
+        let output_schema = Arc::new(Schema::new(vec![Field::new("sum", DataType::Int32, true)]));
+        let mapper_schema = output_schema.clone();
+        let udf = BatchUDF {
+            mapper: Box::new(move |batch: &RecordBatch| {
+                assert!(batch.column_by_name("x").is_some());
+                assert!(batch.column_by_name("y").is_none(), "y was not requested");
+                let x = batch["x"].as_any().downcast_ref::<Int32Array>().unwrap();
+                let doubled: Int32Array = x.iter().map(|v| v.map(|v| v * 2)).collect();
+                Ok(RecordBatch::try_new(
+                    mapper_schema.clone(),
+                    vec![Arc::new(doubled)],
+                )?)
+            }),
+            output_schema,
+            result_checkpoint: None,
+        };
+
+        table
+            .add_columns()
+            .transform(NewColumnTransform::BatchUDF(udf))
+            .read_columns(["x"])
+            .execute()
+            .await
+            .unwrap();
+
+        let schema = table.schema().await.unwrap();
+        assert!(schema.field_with_name("sum").is_ok());
+    }
+}

rust/lancedb/src/table/add_data.rs

@@ -576,10 +576,12 @@ mod tests {
 
         // Add a new physical column AFTER the embedding column.
         table
-            .add_columns(
-                NewColumnTransform::SqlExpressions(vec![("score".into(), "42.0".into())]),
-                None,
-            )
+            .add_columns()
+            .transform(NewColumnTransform::SqlExpressions(vec![(
+                "score".into(),
+                "42.0".into(),
+            )]))
+            .execute()
             .await
             .unwrap();
 
@@ -683,7 +685,9 @@ mod tests {
             true,
         )]));
         table
-            .add_columns(NewColumnTransform::AllNulls(nested_schema), None)
+            .add_columns()
+            .transform(NewColumnTransform::AllNulls(nested_schema))
+            .execute()
             .await
             .unwrap();
 

rust/lancedb/src/table/schema_evolution.rs

@@ -193,10 +193,12 @@ mod tests {
 
         // Add a computed column
         let result = table
-            .add_columns(
-                NewColumnTransform::SqlExpressions(vec![("doubled".into(), "id * 2".into())]),
-                None,
-            )
+            .add_columns()
+            .transform(NewColumnTransform::SqlExpressions(vec![(
+                "doubled".into(),
+                "id * 2".into(),
+            )]))
+            .execute()
             .await
             .unwrap();
 
@@ -251,13 +253,12 @@ mod tests {
 
         // Add multiple columns at once
         table
-            .add_columns(
-                NewColumnTransform::SqlExpressions(vec![
-                    ("y".into(), "x + 1".into()),
-                    ("z".into(), "x * x".into()),
-                ]),
-                None,
-            )
+            .add_columns()
+            .transform(NewColumnTransform::SqlExpressions(vec![
+                ("y".into(), "x + 1".into()),
+                ("z".into(), "x * x".into()),
+            ]))
+            .execute()
             .await
             .unwrap();
 
@@ -283,10 +284,12 @@ mod tests {
 
         // Add a column with a constant value
         table
-            .add_columns(
-                NewColumnTransform::SqlExpressions(vec![("constant".into(), "42".into())]),
-                None,
-            )
+            .add_columns()
+            .transform(NewColumnTransform::SqlExpressions(vec![(
+                "constant".into(),
+                "42".into(),
+            )]))
+            .execute()
             .await
             .unwrap();
 
@@ -659,10 +662,12 @@ mod tests {
 
         // Add column increments version
         let add_result = table
-            .add_columns(
-                NewColumnTransform::SqlExpressions(vec![("c".into(), "a + b".into())]),
-                None,
-            )
+            .add_columns()
+            .transform(NewColumnTransform::SqlExpressions(vec![(
+                "c".into(),
+                "a + b".into(),
+            )]))
+            .execute()
             .await
             .unwrap();
         assert!(add_result.version > v1);

rust/lancedb/tests/blob_integration.rs

@@ -9,14 +9,17 @@ use arrow_array::{
 };
 use arrow_schema::{DataType, Field, Fields, Schema};
 use futures::TryStreamExt;
+use lance::Dataset;
 use lance_encoding::version::LanceFileVersion;
 use lancedb::{
     Connection, Error, Result, Table,
     blob::{BlobRangeRequest, blob},
     connect, connect_namespace,
-    database::listing::OPT_NEW_TABLE_ENABLE_STABLE_ROW_IDS,
+    database::listing::{
+        ListingDatabaseOptions, NewTableConfig, OPT_NEW_TABLE_ENABLE_STABLE_ROW_IDS,
+    },
     query::{ExecutableQuery, QueryBase},
-    table::{AddDataMode, CompactionOptions, OptimizeAction},
+    table::{AddDataMode, CompactionOptions, OptimizeAction, OptimizeStats},
 };
 use tempfile::tempdir;
 
@@ -1075,3 +1078,252 @@ async fn fetch_blob_files_aligns_across_fragments_with_nulls_and_dups() -> Resul
     }
     Ok(())
 }
+
+/// Rows exercising the null/empty interleavings from
+/// <https://github.com/lancedb/lancedb/issues/3744>: a payload, a null, a valid
+/// empty value, then payloads whose descriptors a fragment rewrite used to zero.
+fn null_empty_input_batch() -> RecordBatch {
+    let owned = [
+        Some(dedicated_blob_bytes(1)),
+        None,
+        Some(Vec::new()),
+        Some(dedicated_blob_bytes(4)),
+        Some(dedicated_blob_bytes(5)),
+        Some(dedicated_blob_bytes(6)),
+    ];
+    let payloads: Vec<Option<&[u8]>> = owned.iter().map(|payload| payload.as_deref()).collect();
+    binary_input_batch(&[1, 2, 3, 4, 5, 6], &payloads)
+}
+
+/// One `(id, Some((payload length, first byte)))` per live row, or `(id, None)`
+/// for a null blob.  Comparing lengths and first bytes keeps failure output
+/// readable where comparing whole payloads would not.
+type BlobSummary = Vec<(i64, Option<(usize, Option<u8>)>)>;
+
+/// The rows [`null_empty_input_batch`] leaves behind after `id IN (1, 4)` is
+/// deleted: a null, a valid empty value, and the two payloads that follow them.
+fn expected_null_empty_survivors() -> BlobSummary {
+    vec![
+        (2, None),
+        (3, Some((0, None))),
+        (5, Some((DEDICATED_BLOB_LEN, Some(5)))),
+        (6, Some((DEDICATED_BLOB_LEN, Some(6)))),
+    ]
+}
+
+/// `optimize()` only rewrites a fragment when lance's compaction planner selects
+/// it — here because the delete pushes the fragment past
+/// `materialize_deletions_threshold` (0.1 by default; these tests delete 2 of 6
+/// rows). Without this check, a planner or threshold change upstream would leave
+/// both regression tests green while no rewrite happened at all.
+fn assert_compacted(stats: &OptimizeStats) {
+    let metrics = stats
+        .compaction
+        .as_ref()
+        .expect("OptimizeAction::All runs compaction");
+    assert!(
+        metrics.fragments_removed >= 1,
+        "optimize() rewrote no fragment, so this test proves nothing: {metrics:?}"
+    );
+}
+
+fn summarize(rows: &[(i64, Option<Vec<u8>>)]) -> BlobSummary {
+    rows.iter()
+        .map(|(id, payload)| {
+            (
+                *id,
+                payload
+                    .as_ref()
+                    .map(|bytes| (bytes.len(), bytes.first().copied())),
+            )
+        })
+        .collect()
+}
+
+async fn sorted_id_rowid(table: &Table) -> Result<Vec<(i64, u64)>> {
+    let mut pairs = collect_id_rowid(table).await?;
+    pairs.sort_by_key(|(id, _)| *id);
+    Ok(pairs)
+}
+
+/// `{position, size}` descriptors of a legacy v1 blob column, keyed by `id`.
+async fn v1_blob_descriptors(table: &Table) -> Result<Vec<(i64, Option<(u64, u64)>)>> {
+    let batches = table
+        .query()
+        .execute()
+        .await?
+        .try_collect::<Vec<_>>()
+        .await?;
+    let batch = arrow_select::concat::concat_batches(&batches[0].schema(), &batches).unwrap();
+    let ids = batch
+        .column_by_name("id")
+        .unwrap()
+        .as_any()
+        .downcast_ref::<Int64Array>()
+        .unwrap();
+    let descriptors = batch
+        .column_by_name("image")
+        .unwrap()
+        .as_any()
+        .downcast_ref::<StructArray>()
+        .expect("v1 blob column reads back as a descriptor struct");
+    let position = descriptors
+        .column_by_name("position")
+        .unwrap()
+        .as_any()
+        .downcast_ref::<UInt64Array>()
+        .unwrap();
+    let size = descriptors
+        .column_by_name("size")
+        .unwrap()
+        .as_any()
+        .downcast_ref::<UInt64Array>()
+        .unwrap();
+    let mut rows: Vec<(i64, Option<(u64, u64)>)> = (0..batch.num_rows())
+        .map(|row| {
+            let descriptor =
+                (!descriptors.is_null(row)).then(|| (position.value(row), size.value(row)));
+            (ids.value(row), descriptor)
+        })
+        .collect();
+    rows.sort_by_key(|(id, _)| *id);
+    Ok(rows)
+}
+
+/// Payload bytes of every live row of a legacy v1 blob column, keyed by `id`.
+/// [`Table::fetch_blobs`] rejects v1 columns, so read them through lance.
+async fn v1_blob_payloads(dataset_uri: &str, table: &Table) -> Result<Vec<(i64, Option<Vec<u8>>)>> {
+    let pairs = sorted_id_rowid(table).await?;
+    let row_ids: Vec<u64> = pairs.iter().map(|(_, row_id)| *row_id).collect();
+    let dataset = Arc::new(Dataset::open(dataset_uri).await?);
+    let files = dataset.take_blobs(&row_ids, "image").await?;
+    assert_eq!(
+        files.len(),
+        pairs.len(),
+        "take_blobs returned {} handles for {} live rows",
+        files.len(),
+        pairs.len()
+    );
+    let mut rows = Vec::with_capacity(pairs.len());
+    for ((id, _), file) in pairs.iter().zip(files) {
+        let payload = match file {
+            Some(file) => Some(file.read().await?.to_vec()),
+            None => None,
+        };
+        rows.push((*id, payload));
+    }
+    Ok(rows)
+}
+
+/// Length and first byte of every live blob v2 value, keyed by `id`.
+async fn blob_v2_values(table: &Table) -> Result<BlobSummary> {
+    let pairs = sorted_id_rowid(table).await?;
+    let row_ids: Vec<u64> = pairs.iter().map(|(_, row_id)| *row_id).collect();
+    let bytes = table.fetch_blobs("image", &row_ids).await?;
+    Ok(pairs
+        .iter()
+        .enumerate()
+        .map(|(slot, (id, _))| {
+            let value = (!bytes.is_null(slot))
+                .then(|| (bytes.value(slot).len(), bytes.value(slot).first().copied()));
+            (*id, value)
+        })
+        .collect())
+}
+
+/// Regression test for [#3744]: on storage 2.0 (legacy v1 descriptors),
+/// compaction rewrote every payload following a null or empty value in the same
+/// fragment as `{position: 0, size: 0}`, so the payload bytes read back as `b""`
+/// and the new fragment no longer referenced them at all.
+///
+/// [#3744]: https://github.com/lancedb/lancedb/issues/3744
+#[tokio::test]
+async fn optimize_preserves_v1_blob_payloads_with_null_and_empty() -> Result<()> {
+    let tmp = tempdir().unwrap();
+    let db_uri = tmp.path().to_str().unwrap().to_string();
+    let db = connect(&db_uri)
+        .database_options(&ListingDatabaseOptions {
+            new_table_config: NewTableConfig {
+                data_storage_version: Some(LanceFileVersion::V2_0),
+                ..Default::default()
+            },
+            ..Default::default()
+        })
+        .execute()
+        .await?;
+    let legacy = Field::new("image", DataType::LargeBinary, true).with_metadata(
+        std::collections::HashMap::from([("lance-encoding:blob".to_string(), "true".to_string())]),
+    );
+    let schema = Arc::new(Schema::new(vec![
+        Field::new("id", DataType::Int64, false),
+        legacy,
+    ]));
+    let table = db.create_empty_table("t", schema).execute().await?;
+    table.add(null_empty_input_batch()).execute().await?;
+    assert_eq!(
+        storage_format_version(&table).await,
+        LanceFileVersion::V2_0.resolve(),
+        "v1 blob descriptors only exist below storage 2.2"
+    );
+    let dataset_uri = table.uri().await?;
+
+    // Any rewrite triggers it; deleting rows is the shape from the issue.
+    table.delete("id IN (1, 4)").await?;
+    let descriptors_before = v1_blob_descriptors(&table).await?;
+    let before = v1_blob_payloads(&dataset_uri, &table).await?;
+    assert_eq!(
+        summarize(&before),
+        expected_null_empty_survivors(),
+        "test setup no longer produces the null/empty/payload mix"
+    );
+
+    let stats = table.optimize(OptimizeAction::All).await?;
+    assert_compacted(&stats);
+
+    let descriptors_after = v1_blob_descriptors(&table).await?;
+    let after = v1_blob_payloads(&dataset_uri, &table).await?;
+    assert_eq!(
+        summarize(&after),
+        summarize(&before),
+        "optimize() lost blob payloads; descriptors before={descriptors_before:?} after={descriptors_after:?}"
+    );
+    assert!(after == before, "optimize() changed blob payload bytes");
+    Ok(())
+}
+
+/// Regression test for the blob v2 half of [#3744]: compaction rewrote a valid
+/// empty value as null, destroying the null-vs-empty distinction.
+///
+/// [#3744]: https://github.com/lancedb/lancedb/issues/3744
+#[tokio::test]
+async fn optimize_preserves_blob_v2_null_and_empty_distinction() -> Result<()> {
+    let tmp = tempdir().unwrap();
+    let db = connect(tmp.path().to_str().unwrap()).execute().await?;
+    let table = db
+        .create_empty_table("t", blob_table_schema())
+        .execute()
+        .await?;
+    table.add(null_empty_input_batch()).execute().await?;
+    assert!(
+        storage_format_version(&table).await >= LanceFileVersion::V2_2,
+        "blob v2 columns require storage >= 2.2"
+    );
+
+    table.delete("id IN (1, 4)").await?;
+    let before = blob_v2_values(&table).await?;
+    assert_eq!(
+        before,
+        expected_null_empty_survivors(),
+        "test setup no longer produces the null/empty/payload mix"
+    );
+
+    let stats = table.optimize(OptimizeAction::All).await?;
+    assert_compacted(&stats);
+
+    assert_eq!(
+        blob_v2_values(&table).await?,
+        before,
+        "optimize() changed blob v2 values"
+    );
+    Ok(())
+}