# Parallel Hash Join (The Bucket Brigade)
When the Elephant is performing a **Hash Join** across multiple workers, he must coordinate the allocation and building of the hash tables. If these events are high, it means the workers are "fighting" over who gets to fill the bucket.
![[HashBatchAllocate]]
![[HashBatchElect]]
![[HashBatchLoad]]
![[HashGrowBatchesDecide]]
![[HashGrowBatchesElect]]
![[HashGrowBatchesFinish]]
![[HashGrowBatchesReallocate]]
![[HashGrowBatchesRepartition]]
![[HashGrowBucketsElect]]
![[HashGrowBucketsReallocate]]
![[HashGrowBucketsReinsert]]
![[HashBuildAllocate]]
![[HashBuildElect]]
![[HashBuildHashInner]]
![[HashBuildHashOuter]]