### What problem does this PR solve?

Issue Number: None

Related PR: #65730 #66608 #66805 #66841 #66999 #67005 #67011 #67110
#67268 #67289 #67325 #67650 #67921 #68028 #68335 #68375 #68615 #68690
#68813 #68815 #68707 #68649

Problem Summary:

**In short.** This ports the Lance BE read path of branch-4.1 /
branch-4.2 to master, in its branch-4.2 form as of `cabcf45c1af`, plus
the BE side of three 4.x changes merged after that snapshot: the search
filter `prefilter` flag and profile layout (#68813), distance bounds for
`vector_search` (#68815), and the split-level index rule of #68707 that
#68815 relies on. It gathers the BE parts of the PRs listed above.
Master links `liblance_c` but has no Lance reader, so every
`FORMAT_LANCE` scan fails today. With this PR the BE reads Lance
datasets through FileScannerV2: plain scans, vector search and full-text
search, predicate and runtime-filter pushdown, the schema fetch of a
local Lance TVF, and the second phase of TopN lazy materialization. The
PR is BE only. The FE connector plugin and the regression suites come in
separate PRs, so until then nothing on master plans a Lance scan, and
the BE unit tests carry the proof.

Original authors: @zhangstar333 @Gabriel39 @wangzhaobo957-cloud @Jay-ju
@FANNG1

**Background.** Lance shipped in 4.1.4: the Lance catalog, `local()` /
`s3()` with `format=lance`, and the `vector_search` / `full_text_search`
TVFs. On master the FE side is being rebuilt as a connector plugin
(`fe-connector-lance`), and the BE needs the reader from 4.x. The thrift
ids are the branch-4.1 / 4.2 ones, including `TExternalSearchRequest.5`
(`prefilter`) and `TVectorSearchParams.6/7` (distance bounds) added
after the snapshot, so a BE built from master also reads the Lance scan
ranges and search requests that a 4.x FE sends during a rolling upgrade.
The one exception is `TVectorSearchOptions` 6, branch-4.2's
`approx_mode` (#69852, merged into branch-4.2 after the snapshot and not
ported): it is reserved in a comment, and a master BE ignores it, so
during a rolling upgrade a 4.2 FE that asks for `fast` or `accurate`
gets Lance's default (`normal`).

**The problem, and what it cost.**

| | master today | with this PR |
|---|---|---|
| A `FORMAT_LANCE` scan | FileScannerV2 has no Lance reader, so the scan
fails with "FileScannerV2 does not support file format" | read by
`LanceTableReader` in FileScannerV2 |
| `fetch_table_schema` for a local Lance TVF | not handled | returns the
Arrow schema mapped to Doris types; Null leaves keep `NULL_TYPE` |
| The row location of a Lance row in TopN lazy materialization |
`GlobalRowLoacationV2` only has a 32-bit row id, but a Lance row id is a
64-bit id within the snapshot | a version 1 layout carries the 64-bit
row id; phase two reads the rows with the dataset's `take_rows` |

**How this PR fixes it.**

- Reader: `be/src/format_v2/lance/*` and
`be/src/format_v2/table/lance_reader.*`, as on branch-4.2 except one
local renamed for master's `-Wshadow`. The unit tests construct
`RuntimeState(TQueryOptions(), globals)`, because master removed the
globals-only constructor.
- FileScannerV2: the reader dispatch and `_to_file_format` handle
`FORMAT_LANCE` / `"lance"`; `FileFormat::LANCE` is added to its two
exhaustive switches. Since #69723 every file scan uses FileScannerV2, so
nothing else routes Lance scans (on branch-4.2 a Lance query fails with
NotSupported when `enable_file_scanner_v2` is off).
- Row locations: `ROW_VERSION {FILE_LOCAL_ROW_ID = 0,
LANCE_DATASET_ROW_ID = 1}` and a union layout for
`GlobalRowLoacationV2`. Version 0 keeps its byte layout, which static
asserts pin. `PRequestBlockDesc.row_id` becomes `uint64` (a proto2
varint, so the wire format is compatible). The materialization operator
decodes row locations by version, rejects an unknown version or a wrong
size, and stamps `row_location_version`. `RowIdStorageReader` validates
the counts and the version, range-checks internal row ids against
`uint32`, and groups Lance rows by plan node, snapshot version and
dataset URI, so each dataset is read with one `take_rows`. Master's
segment batching, scan-slot dedup and fetch concurrency stay as they
are.
- Thrift (`PlanNodes.thrift`): the external search request body
(`TVectorElementType`, `TVectorMetric`, `TSearchVector`,
`TVectorSearchParams` 1-7, `TFtsCoverageMode`, `TFtsQueryType`,
`TFtsMatchOperator`, `TFullTextSearchParams`, `TSearchFilterFormat`,
`TSearchFilter`, `TVectorSearchOptions`, `TExternalSearchQuery`),
`TExternalSearchRequest` 2-5 and `TLanceFileDesc` 4-6, all with the
branch-4.1 / 4.2 ids. The enums spell out their 4.x values. No id is
reused. On master, #70075 reserved `TExternalSearchRequest` 2-5 in
comments and added 6 (`paimon_options`); this PR replaces those comments
with the fields and leaves 6 as it is. `TVectorSearchOptions` 6 is
reserved in a comment for branch-4.2's `approx_mode` (#69852).
- After the snapshot (one commit each):
- #68813: `prefilter` decides whether the TVF search filter runs before
(true) or after (unset / false) candidate selection, for vector and
full-text search. The profile groups the Lance counters under
`LanceTiming`, `LanceIO`, `LanceIndex`, `LanceVectorIndex`,
`LanceScalarIndex`, `LanceExecutionPlan`, `LanceScan`, `LanceSearchPlan`
and `LanceDataCache`, uses the 4.x counter names, and registers every
scan metric before the statistics callback is installed, so the
callback, which Lance invokes from its execution streams, never adds
counters. #68813's FE tweak that hides `TUnit.NONE` labels in
`AggCounter` belongs to the FE port.
- #68707 (part): a vector split searches exactly the index segments FE
planned for it, and a split without segments is searched flat whatever
`use_index` says; a split with segments under `use_index = false` is
rejected. 4.x FEs plan segments only when `use_index` allows them.
- #68815: `distance_lower_bound` (inclusive) and `distance_upper_bound`
(exclusive) are validated (finite FLOAT values, lower < upper at FLOAT
precision, single-vector only) and installed with
`lance_scanner_set_distance_range()`, which master's pinned lance-c
provides.
- Review fixes:
- A nested array goes to the Doris SerDes without a copy only when it
and every descendant start at offset 0 and reference exactly their child
ranges. Lance's legacy (v1) decoder can return a struct or list that is
tight at its own level over a Boolean child with a bit offset (a batch
that starts mid-byte in the bitmap), and the SerDes reject that under
Arrow input validation.
- A zero-field `STRUCT<>`, which Lance decodes, is reported as an
unsupported column at any nesting level, like the other unsupported
Lance types. It used to be typed as a STRUCT that `ColumnStruct` cannot
hold (its row count comes from its first child).
- A Lance Decimal256 field with precision <= 38 is narrowed to
Decimal128 by a safe Arrow cast before decoding. Doris types it
DECIMAL32/64/128I by precision, and those SerDes read only Decimal128
arrays; the BE used to crash on the first value, also for nested leaves.
Only values a reader can see are cast: before a nested leaf is narrowed,
every child slot that no visible row references (under a NULL list,
fixed-size-list, map or struct row, or outside a sliced parent) is
marked NULL, so a hidden value does not fail the cast and a visible
value outside the declared precision still does; map keys, which cannot
be NULL, stay checked.
- FLOAT / DOUBLE `>=` runtime filters stay residual-only. Lance compares
floats by totalOrder, so a pushed `x >= c` dropped negative-NaN rows
that Doris keeps.
- Runtime filters that mention INT64_MIN stay residual-only. The pinned
Lance SQL parser reads `-9223372036854775808` as the negation of a
magnitude that it parses as i64 first; the overflow turns the literal
into a Float64, which the planner cannot coerce to Int64 or Decimal, so
a pushed IN, `>=` or `<=` filter on an INT64 or scale-zero decimal
column failed planning and the query failed. Every other i64 is still
pushed.
- The shared Arrow DATE32 decoding
(`DataTypeDateV2SerDe::read_column_from_arrow`) rejects days outside
0000-01-01..9999-12-31 instead of returning a non-null `0000-00-00`,
skips null slots and adds the epoch in 64 bits: the DATE32 range part of
branch-4.1 / 4.2 #68649. It also changes ADBC, Arrow stream load and
paimon-rust reads.
- Child values hidden by a NULL list, fixed-size-list, map or struct row
are not decoded: the array, map and struct SerDes give the element SerDe
a validity bitmap that also clears those slots
(`mask_arrow_children_hidden_by_null_parents()`). Arrow leaves them
unspecified, and Lance's v2.1 miniblock encoding keeps them, so a hidden
10000-01-01 under a NULL fixed-size list used to fail the DATE32 range
check above. Visible values are unchanged; this applies to ADBC, Arrow
stream load and paimon-rust as well. The masks come from ExecEnv's
tracked Arrow pool. A nested Lance array that is compacted before
decoding is masked the same way, at every level, before its
`ValidateFull()`, so a hidden invalid UTF-8 string, out-of-precision
decimal, Date64 or time no longer fails the batch while a visible one
still does. Since #69697 the same masks keep hidden DATETIMEV2 /
TIMESTAMPTZ values out of its range checks. A mask costs at most one
pass per batch: a NULL row that owns no child slots, or only NULL ones,
allocates nothing, and Arrow stream load masks each retained IPC batch
once (`mask_arrow_descendants_not_visible()`) before it hands row ranges
to the SerDes, so its per-block reads allocate nothing. The one
per-block mask left is for map keys under a NULL map row that still owns
entries, since a MapArray cannot hold NULL keys; Arrow's map builder
writes NULL map rows without entries.
- Core: `to_protobuf` keeps `NULL_TYPE` for a NULL literal type, so a
Null leaf in ARRAY / MAP / STRUCT no longer comes back as BOOLEAN. The
nullable serde reads an Arrow Null array as NULLs without touching
buffers that the array does not have.
- Configs, caches and metrics, with the 4.x names and defaults:

  | Config | Default |
  |---|---|
  | `lance_index_cache_size_bytes` | 10 GiB |
  | `lance_metadata_cache_size_bytes` | 1 GiB |
  | `enable_lance_data_cache` | true |
  | `lance_data_cache_path` | `${DORIS_HOME}/lance_data_cache` |
  | `lance_data_cache_disk_capacity_bytes` | 100 GiB |
  | `lance_data_cache_read_block_size_bytes` | 1 MiB |
  | `lance_io_buffer_size_bytes` (mutable) | 2 GiB |
  | `lance_batch_readahead` (mutable) | 5 |
  | `lance_fragment_readahead` (mutable) | 5 |

The BE-wide Lance session (index cache, metadata cache and the optional
Foyer disk cache) is created by the first Lance scan, so a BE that never
reads Lance creates no cache directory. The first six configs take
effect after a restart. A negative cache size (and, while the data cache
is enabled, a negative disk capacity or read block size) fails the first
Lance scan with a message that names the setting, as does any data-cache
value lance-c rejects; the rest of the BE keeps serving. Ten
`lance_session_*` metrics report the two in-memory caches. With the
defaults, the disk tier keeps 51,200 sparse 2 MiB block files open from
the first Lance scan on (100 GiB in blocks of twice the read block
size), the same as on branch-4.1 / 4.2. Size
`lance_data_cache_disk_capacity_bytes` and
`lance_data_cache_read_block_size_bytes` against the BE's open-file
limit, or set `enable_lance_data_cache = false`.

The index and metadata caches live in lance-c memory: they are not
charged to a MemTracker or registered with CacheManager, so memory GC,
the cache capacity adjustment under memory pressure and
`/api/clear_cache/all` do not shrink them, and `enable_lance_data_cache
= false` does not turn them off. lance-c has no call to clear, evict or
resize them, so size them with the two configs. The disk tier keys
blocks by Lance's store prefix (`scheme$bucket` for S3, GCS and OSS,
without the endpoint) and the object path
(`thirdparty/patches/lance-c-foyer.patch`). Several endpoints that serve
the same bucket name and data-file path with different bytes (data files
registered under chosen names or replaced in place; Lance's writers use
random file names) share entries, also across a BE restart; such a
deployment should set `enable_lance_data_cache = false`. Both are as on
branch-4.1 / 4.2 and tracked as follow-ups.

A Lance scan's native working set, that is the I/O buffered up to
`lance_io_buffer_size_bytes` per scanner, the decode readahead and the
operators of a search plan such as the top-k of a flat vector search, is
allocated inside lance-c and is charged to neither the query nor its
workload group. It counts toward the BE process memory only, so memory
GC, which ranks queries by tracked memory, does not attribute it to the
Lance query. lance-c accepts no memory budget, so on BEs with little
memory headroom size `lance_io_buffer_size_bytes`,
`lance_batch_readahead` and `lance_fragment_readahead` for the number of
concurrent Lance scanners. As on branch-4.1 / 4.2; tracked as a
follow-up.
- Build: macOS links `-framework IOKit`. This is the first time objects
of `liblance_c.a` are pulled into `doris_be`, so the binary and the link
time grow. With this PR `util/rle_encoding.h` reaches 231 TUs and
`util/threadpool.h` 589, the same as master `315c2e00331` alone (limits
275 and 660 since #69717), and `gen_cpp/internal_service.pb.h` 562
(master alone 559, limit 660); the reach budgets are unchanged.

Not included: the Lance index metadata scanner (`LANCE_INDEX_ENTRIES`);
the FE side, including the rolling-upgrade guard that keeps Lance lazy
materialization off while an old BE could decode a version 1 row
location as version 0; the regression suites; the rest of #68707
(searching historical versions, tags and branches, rejecting fragment
ids missing from the snapshot, naming the snapshot in errors and the
profile). The `InitReaderAvgTime` / `GetBlockAvgTime` profile fix that
#67005 carried goes in a separate PR.

**Results.**

| | master | with this PR |
|---|---|---|
| A `FORMAT_LANCE` query | fails before reading anything | read by
`LanceTableReader` in FileScannerV2 |
| A Lance row in the second phase of TopN lazy materialization | cannot
be represented | a version 1 row location, read back with `take_rows` |
| A row location of an unknown version or size in phase two | decoded as
version 0 | rejected with an error |
| An Arrow DATE32 day outside 0000-01-01..9999-12-31 (ADBC, Arrow stream
load, paimon-rust, Lance) | read as a non-null `0000-00-00` | the read
fails with `InvalidArgument` |

BE unit tests (ASAN, macOS arm64, against master's pinned lance-c), on
the head rebased onto master `378404eeb12`: 1029 cases in 54 suites run,
1027 pass and 2 Parquet microbenchmarks skip by design. They cover the
Lance suites (107: `LanceTableReader*` 83, `LanceNestedNullTest` 10,
`LanceRuntimeFilterHelperTest` 10, `LanceSessionManagerTest` 4); the
row-location protocol (`MaterializationSharedStateTest`,
`RowIdStorageReaderTest`, and the new `RowIdFetchRequestValidationTest`:
count mismatch, unknown version, a Lance version on an internal mapping,
an internal row id of 2^32); `FileScannerV2Test` (28); the ORC and
Parquet reader suites (`NewOrcReaderTest`, `NewParquetReaderTest`,
`ParquetScanTest` and the other `Parquet*` suites), whose row ids now go
through `file_local`; and the Arrow / protobuf / DATE serde suites with
the new `ArrowParentNullsTest`, plus the Iceberg and Parquet reader
suites that decode Arrow dates. Reverting any of the review fixes, the
#68813 flag, the #68707 split rule or the #68815 bounds makes its new
tests fail. The sixth review round adds 13 cases (`ArrowParentNullsTest`
10, `LanceTableReaderTypeTest` 3) and extends one; with them the Arrow
SerDe, Lance, ADBC and `IcebergV2ReaderTest` suites run 317 cases: 310
pass and the 7 ADBC SQLite cases skip without a local SQLite driver. The
ninth review round adds
`LanceRuntimeFilterHelperTest.KeepsInt64MinFiltersResidualOnly` and
`LanceTableReaderFilterTest.KeepsInt64MinRuntimeFiltersOutOfLanceScanner`:
both pass with the 106 Lance cases (`Lance*`) on the branch rebased onto
`339e087b11f`, and restoring `parse_int64()` in either check makes
exactly these two fail. On the head rebased onto master `315c2e00331`,
with the per-block mask fix (`42cf4e3e5d1`), 328 cases in 24 suites
pass: the Arrow SerDe and validation suites, `ArrowParentNullsTest`
(15), `LoadArrowPipeTest` (47), the DATETIMEV2 / TIMESTAMPTZ SerDe
suites, `ArrowColumnToDorisColumnTest`, `ArrowBlockConvertorTest`,
`AdbcReaderTest`, `RemoteDorisV2ReaderTest`, `PaimonRustTableReaderTest`
and the Lance suites. Allocating at the first NULL row of each call
again fails the new `ArrowParentNullsTest` case and the four new
`LoadArrowPipeTest` block cases, dropping the per-batch mask fails the
LIST and STRUCT block cases, and returning the child unmasked fails the
new timestamp case, four `ArrowParentNullsTest` cases and
`LanceTableReaderTypeTest.IgnoresDate32PayloadHiddenByNullParents`.

### Release note

Add nine `lance_*` BE configs and `lance_session_*` BE metrics. They
take effect once the FE can plan Lance scans. Reading an Arrow DATE32
value outside 0000-01-01..9999-12-31 through ADBC, Arrow stream load or
paimon-rust now fails instead of returning 0000-00-00.

### Check List (For Author)

- Test <!-- At least one of them must be included. -->
    - [ ] Regression test
    - [x] Unit Test
- `run-be-ut.sh --run --filter=...` with the suites listed under
Results: 420 of 420 pass on macOS arm64 (ASAN) on the content before the
rebases, and the Lance and Arrow SerDe suites pass again with the
nested-offset, zero-field struct, hidden-child, hidden-Decimal256 and
compaction-mask fixes (the ADBC SQLite cases skip without a local SQLite
driver). Rebased onto master `43f9ceb48d7`: #69668 conflicted in the
scanner selection and in `fetch_table_schema`, which now hands every
file format to `format::fetch_file_schema()`, so the Lance branch runs
ahead of that call; #69646 added a TopN row-group test that reads the
version 0 row location fields, which now go through `file_local` (the
earlier rebase onto `5caaeb3e3d4` resolved #69614 and #69601 in the
scanner selection, the `FileFormat` enum, its test and the reach budget
table). The 95 TUs that this PR changes or that master changed since
`5caaeb3e3d4` were syntax-checked against the rebased tree with the UT
build flags, and CI runs the suites again. Rebased again onto master
`8d88f1cc6f7`: the only conflict was the budget table, where #65858
moved the `util/rle_encoding.h` baseline to 828, and the 163 TUs that
this PR changes or that master changed since `43f9ceb48d7` pass the same
syntax check. Rebased again onto master `339e087b11f`: the only conflict
was the budget table again, where #67292 moved the `util/rle_encoding.h`
baseline to 834; #69872 added Arrow type checks ahead of the NULL-parent
masking in the map and struct readers and merged cleanly. Of the 114
sources that this PR changes or that master changed since `8d88f1cc6f7`,
111 pass the same syntax check. The other three are master's: two new
#67292 files under `storage/segment` fail the same way on master alone,
since they compile only inside their unity batch, and this PR adds no
source to that target; the #69818 benchmark is not in the UT build and
includes only `util/simd` headers that this PR does not touch. Reverting
any of the review fixes, the #68813 flag, the #68707 split rule or the
#68815 bounds makes its new tests fail. Rebased again onto master
`378404eeb12`, which removed the legacy file scanner (#69723): the
conflicts were in the scanner-selection code and tests that #69723
deleted, so this PR's Lance lines there went with them (including its
`LanceQueriesAlwaysUseScannerV2` test), in the profile keys of
`materialization_opertor.cpp`, and in the row fetch of
`rowid_fetcher.cpp`, whose non-Lance path is now only
`FileScannerV2::read_by_rows`; the deleted V1 ORC / Parquet row id tests
took this PR's `file_local` rename with them, and the
`util/rle_encoding.h` budget commit is dropped because master is no
longer near that limit. Of the 100 sources that this PR changes or that
master changed since `339e087b11f`, 99 pass the same syntax check; the
other, `format_v2/orc/orc_reader.cpp`, fails the same way on master
alone. On the rebased head the suites listed under Results run 1029
cases: 1027 pass and 2 microbenchmarks skip. The test-utility fix that
`DataTypeDateTimeV2SerDeTest` needed on macOS (#69695) is now on master.
Rebased again onto master `315c2e00331`: the only conflict was
`TExternalSearchRequest` in `PlanNodes.thrift`, where #70075 had
reserved fields 2-5 in comments; the two commits that add the fields
replace those comments, and field 6 stays #70075's `paimon_options`.
#69717 cut transitive includes from shared headers: of the 160 sources
that this PR changes or that master changed since `378404eeb12`, 156
pass the same syntax check; the two `jemalloc_hook` tests have no
compile command on macOS, `runtime/memory/jemalloc_hook.cpp` uses glibc
aliases that macOS cannot build (#69819), and
`format_v2/table_reader.cpp` alone fails the same way on master alone
while its unity batch compiles. The full `doris_be_test` builds and
links on the rebased head; `ArrowParentNulls*` and `Lance*` (121 cases)
pass before the mask fix, and the 328 cases above with it.
- `build-support/check-build-hygiene.sh` (on this branch rebased onto
master `315c2e00331`), clang-format 16 and
`build-support/run-clang-tidy.sh` on the changed files: all pass; on the
changed lines clang-tidy (llvm 22) reports only
`readability-inconsistent-ifelse-braces` on the `DORIS_CHECK` lines of
the masking functions, the macro's expansion that master's existing
`DORIS_CHECK`s report too.
    - [ ] Manual test (add detailed scripts or steps below)
    - [ ] No need to test or manual test. Explain why:
- Behavior changed:
    - [ ] No.
- [x] Yes. `PRequestBlockDesc.row_id` is `uint64`; phase two of TopN
lazy materialization rejects row locations of an unknown version or
size; `FORMAT_LANCE` scans run on FileScannerV2; an Arrow DATE32 day
outside the Doris DATE range fails the read instead of becoming
`0000-00-00`.
- Does this need documentation?
    - [x] No. Lance is documented with the FE connector.
- [ ] Yes. <!-- Add document PR link here. eg:
apache/doris-website#1214 -->

### Check List (For Reviewer who merge this PR)

- [ ] Confirm the release note
- [ ] Confirm test cases
- [ ] Confirm document
- [ ] Add branch pick label <!-- Add branch pick label that this PR
should merge into -->

---------

Co-authored-by: zhangstar333 <[email protected]>
Co-authored-by: Gabriel <[email protected]>
Co-authored-by: zhaobo wang <[email protected]>
Co-authored-by: jay <[email protected]>
Co-authored-by: FANNG <[email protected]>
Co-authored-by: Claude Opus 5.5 (1M context) <[email protected]>
Co-authored-by: zy-kkk <[email protected]>