laminar_core/tpc/
router.rs

1//! Key routing specification and error types.
2//!
3//! Provides [`KeySpec`] for specifying how events are partitioned across cores
4//! and [`RouterError`] for routing failures.
5
6/// Routing errors with no heap allocation.
7///
8/// All error variants use static strings to avoid allocation on error paths,
9/// which is critical for Ring 0 hot path performance.
10#[derive(Debug, Clone, Copy, PartialEq, Eq, thiserror::Error)]
11pub enum RouterError {
12    /// A column specified by name was not found in the schema.
13    #[error("column not found by name")]
14    ColumnNotFoundByName,
15
16    /// A column index is out of range for the batch.
17    #[error("column index out of range")]
18    ColumnIndexOutOfRange,
19
20    /// A row index is out of range for the array.
21    #[error("row index out of range")]
22    RowIndexOutOfRange,
23
24    /// The data type is not supported for key extraction.
25    #[error("unsupported data type for routing")]
26    UnsupportedDataType,
27
28    /// The batch is empty and cannot be routed.
29    #[error("empty batch")]
30    EmptyBatch,
31}
32
33/// Specifies how to extract routing keys from events.
34///
35/// The key determines which core processes an event. All events with the
36/// same key are guaranteed to go to the same core.
37#[derive(Debug, Clone, Default)]
38pub enum KeySpec {
39    /// Use specific column names as the key.
40    ///
41    /// The columns are concatenated in order to form the key.
42    Columns(Vec<String>),
43
44    /// Use column indices as the key.
45    ///
46    /// Useful when column names are not known or for performance.
47    ColumnIndices(Vec<usize>),
48
49    /// Round-robin distribution (no key).
50    ///
51    /// Events are distributed evenly across cores without regard to content.
52    /// Use this when state locality is not required.
53    #[default]
54    RoundRobin,
55
56    /// Use all columns as the key.
57    ///
58    /// The entire row is hashed to determine routing.
59    AllColumns,
60}
laminar_core/tpc/router.rs

laminar_core/tpc/
router.rs
