feat: support table partitioning policies

[sshaplygin]

Closes #311.

CreateTableRequest only carried path, columns, primary key and attributes, so partitioning could not be configured from the Rust SDK at all. This adds the table-side equivalent of ydb-go-sdk's options.WithPartitioningSettings, WithUniformPartitions and WithExplicitPartitions.

API

table_client.create_table(
    CreateTableRequest::new(path)
        .with_column(TableColumn::new("id", Value::Uint64(0)))
        .with_primary_key(["id"])
        .with_partitioning_settings(
            TablePartitioningSettings::new()
                .with_partitioning_by_size(true)
                .with_partition_size_mb(128)
                .with_min_partitions_count(2)
                .with_max_partitions_count(16),
        )
        .with_uniform_partitions(4),
).await?;

Added	Purpose
TablePartitioningSettings	Auto-partitioning policy and partition-count bounds
CreateTableRequest::with_partitioning_settings	Policy for a new table
CreateTableRequest::with_uniform_partitions / with_partition_at_keys	Initial partition layout (the partitions oneof)
AlterTableRequest::alter_partitioning_settings	Change the policy of an existing table
TableDescription::partitioning_settings	Read the policy back

Every settings field is Option, mirroring the tri-state feature flags on the wire: unset means "server default" on create and "leave alone" on alter. Zero counts coming back from the server decode as None, so a describe result round-trips into an alter request unchanged.

Two things worth reviewing

Naming. The types are TablePartitioningSettings and TablePartitions, not the unprefixed names. The crate re-exports everything flat from the root, and PartitioningSettings is already the topic client's type — Go avoids the clash with separate packages, which is not available here. Happy to rename if you prefer a different convention.

Explicit split points needed the server to pin down. A split point is a prefix of the primary key, so YDB expects Tuple<Optional<T>, ...>. Sending a bare scalar is rejected with Partition ranges are not sorted at index 0 even when the values are strictly ascending — which is what my first attempt did. The public Value has no tuple variant yet (#309), so with_partition_at_keys takes one Vec<Value> per split point and builds the tuple in the raw layer:

.with_partition_at_keys([vec![Value::Uint64(100)], vec![Value::Uint64(200)]])

If #309 lands a Value::Tuple, this can be simplified without changing the signature.

Verification

Against ydbplatform/local-ydb:nightly, the image CI uses. Three integration tests, all exercising a real server:

• settings survive create → describe, and alter → describe;
• with_uniform_partitions applies;
• explicit split points place rows across partitions (checked with bulk_upsert + read_rows), and descending split points are rejected.

Unit tests cover the feature-flag tri-state and the zero-count decoding.

cargo test --workspace -- --include-ignored   # 309 passed, 0 failed
cargo test -p ydb --doc                       # 32 passed
cargo fmt --check
cargo clippy --workspace --all-targets --no-deps --exclude=ydb-grpc -- -D warnings

Not included

The legacy TableProfile.PartitioningPolicy message (preset names, AUTO_SPLIT / AUTO_SPLIT_MERGE) is untouched — PartitioningSettings is the modern replacement and the one the Go SDK's documented options map onto. Say the word if parity there is wanted too.

🤖 Generated with Claude Code

[codecov]

Codecov Report

❌ Patch coverage is 96.66667% with 10 lines in your changes missing coverage. Please review.
✅ Project coverage is 87.05%. Comparing base (a6d7911) to head (726a4a3).

Files with missing lines	Patch %	Lines
ydb/src/table_requests.rs	90.56%	10 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##           master     #596      +/-   ##
==========================================
+ Coverage   86.91%   87.05%   +0.14%     
==========================================
  Files         198      199       +1     
  Lines       19492    19788     +296     
==========================================
+ Hits        16941    17227     +286     
- Misses       2551     2561      +10     

Flag	Coverage Δ
rust-1.88.0	87.05% <96.66%> (+0.14%)	⬆️
rust-1.96.1	87.30% <96.66%> (+0.14%)	⬆️
tests	87.05% <96.66%> (+0.14%)	⬆️
ubuntu	87.05% <96.66%> (+0.14%)	⬆️

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