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Set HashJoin seed #15783

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Merged
merged 4 commits into from
Apr 29, 2025
Merged

Set HashJoin seed #15783

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49491fa
Set HashJoin seed
ctsk Apr 20, 2025
231629a
fmt
ctsk Apr 20, 2025
af232c6
whitespace grr
ctsk Apr 20, 2025
e1fc96d
Document hash seed
ctsk Apr 22, 2025
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6 changes: 5 additions & 1 deletion datafusion/physical-plan/src/joins/hash_join.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -86,6 +86,10 @@ use datafusion_physical_expr_common::physical_expr::fmt_sql;
use futures::{ready, Stream, StreamExt, TryStreamExt};
use parking_lot::Mutex;

/// Hard-coded seed to ensure hash values from the hash join differ from `RepartitionExec`, avoiding collisions.
const HASH_JOIN_SEED: RandomState =
RandomState::with_seeds('J' as u64, 'O' as u64, 'I' as u64, 'N' as u64);
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Love it


/// HashTable and input data for the left (build side) of a join
struct JoinLeftData {
/// The hash table with indices into `batch`
Expand Down Expand Up @@ -385,7 +389,7 @@ impl HashJoinExec {
let (join_schema, column_indices) =
build_join_schema(&left_schema, &right_schema, join_type);

let random_state = RandomState::with_seeds(0, 0, 0, 0);
let random_state = HASH_JOIN_SEED;

let join_schema = Arc::new(join_schema);

Expand Down