Optimize coalesce (#508)

fpetkovski · web-flow · commit 1630e99ad49b · 2025-01-13T15:22:13.000Z
If coalesce has a single downstream operator, we can skip it
and directly return the downstream.

Signed-off-by: Filip Petkovski &lt;filip.petkovsky@gmail.com&gt;
diff --git a/execution/exchange/coalesce.go b/execution/exchange/coalesce.go
@@ -53,6 +53,9 @@ type coalesce struct {
 }
 
 func NewCoalesce(pool *model.VectorPool, opts *query.Options, batchSize int64, operators ...model.VectorOperator) model.VectorOperator {
+	if len(operators) == 1 {
+		return operators[0]
+	}
 	oper := &coalesce{
 		pool:          pool,
 		sampleOffsets: make([]uint64, len(operators)),

Original file line number	Diff line number	Diff line change
`@@ -53,6 +53,9 @@ type coalesce struct {`
`53`	`53`	`}`
`54`	`54`
`55`	`55`	`func NewCoalesce(pool model.VectorPool, opts query.Options, batchSize int64, operators ...model.VectorOperator) model.VectorOperator {`
	`56`	`+ if len(operators) == 1 {`
	`57`	`+ return operators[0]`
	`58`	`+ }`
`56`	`59`	`oper := &coalesce{`
`57`	`60`	`pool: pool,`
`58`	`61`	`sampleOffsets: make([]uint64, len(operators)),`