cspann: pass tree key to delete vector fixup

Previously, the delete vector fixup did not take a tree key parameter,
which meant it always searched the default tree for the vector to
delete. This commit fixes that by passing the tree key to the fixup.

Epic: CRDB-42943
Release note: None

Author: andy-kimball

pkg/sql/vecindex/cspann/fixup_processor.go

@@ -287,9 +287,10 @@ func (fp *FixupProcessor) DelayInsertOrDelete(ctx context.Context) error {
 
 // AddDeleteVector enqueues a vector deletion fixup for later processing.
 func (fp *FixupProcessor) AddDeleteVector(
-	ctx context.Context, partitionKey PartitionKey, vectorKey KeyBytes,
+	ctx context.Context, treeKey TreeKey, partitionKey PartitionKey, vectorKey KeyBytes,
 ) {
 	fp.addFixup(ctx, fixup{
+		TreeKey:      treeKey,
 		Type:         vectorDeleteFixup,
 		PartitionKey: partitionKey,
 		VectorKey:    vectorKey,

pkg/sql/vecindex/cspann/index.go

@@ -921,8 +921,8 @@ func (vi *Index) getFullVectors(
 			// the case of a dangling partition key.
 			if candidates[i].ChildKey.KeyBytes != nil {
 				// Vector was deleted, so add fixup to delete it.
-				vi.fixups.AddDeleteVector(
-					ctx, candidates[i].ParentPartitionKey, candidates[i].ChildKey.KeyBytes)
+				vi.fixups.AddDeleteVector(ctx, idxCtx.treeKey,
+					candidates[i].ParentPartitionKey, candidates[i].ChildKey.KeyBytes)
 			}
 
 			// Move the last candidate to the current position and reduce size

pkg/sql/vecindex/cspann/testdata/tree-key.ddt

@@ -106,3 +106,70 @@ format-tree
 ├───• vec1 (1, 2)
 ├───• vec2 (7, 4)
 └───• vec3 (4, 3)
+
+# ----------------------------------------------------------------------
+# Test delete vector fixup in non-default tree.
+# ----------------------------------------------------------------------
+new-index min-partition-size=2 max-partition-size=4 beam-size=2 tree=1
+vec1: (1, 2)
+vec2: (7, 4)
+vec3: (4, 3)
+vec4: (8, 11)
+vec5: (14, 1)
+vec6: (0, 0)
+----
+• 1 (0, 0)
+│
+├───• 2 (1.6667, 1.6667)
+│   │
+│   ├───• vec1 (1, 2)
+│   ├───• vec6 (0, 0)
+│   └───• vec3 (4, 3)
+│
+└───• 3 (9.6667, 5.3333)
+    │
+    ├───• vec4 (8, 11)
+    ├───• vec5 (14, 1)
+    └───• vec2 (7, 4)
+
+# Delete vector from primary index, but not from secondary index.
+delete not-found tree=1
+vec1
+----
+• 1 (0, 0)
+│
+├───• 2 (1.6667, 1.6667)
+│   │
+│   ├───• vec1 (MISSING)
+│   ├───• vec6 (0, 0)
+│   └───• vec3 (4, 3)
+│
+└───• 3 (9.6667, 5.3333)
+    │
+    ├───• vec4 (8, 11)
+    ├───• vec5 (14, 1)
+    └───• vec2 (7, 4)
+
+# Ensure deleted vector is not returned by search. This should enqueue a fixup
+# that removes the vector from the index.
+search max-results=1 tree=1
+(1, 2)
+----
+vec6: 5 (centroid=2.36)
+6 leaf vectors, 8 vectors, 2 full vectors, 3 partitions
+
+# Vector should now be gone from the index.
+format-tree tree=1
+----
+• 1 (0, 0)
+│
+├───• 2 (1.6667, 1.6667)
+│   │
+│   ├───• vec3 (4, 3)
+│   └───• vec6 (0, 0)
+│
+└───• 3 (9.6667, 5.3333)
+    │
+    ├───• vec4 (8, 11)
+    ├───• vec5 (14, 1)
+    └───• vec2 (7, 4)