Fixed failed to add index item error with sparsevec - fixes #625

test/t/038_hnsw_sparsevec_vacuum_insert.pl

@@ -0,0 +1,38 @@
+use strict;
+use warnings;
+use PostgresNode;
+use TestLib;
+use Test::More;
+
+# Initialize node
+my $node = get_new_node('node');
+$node->init;
+$node->start;
+
+# Create table and index
+$node->safe_psql("postgres", "CREATE EXTENSION vector;");
+$node->safe_psql("postgres", "CREATE TABLE tst (i serial, v sparsevec(100000));");
+$node->safe_psql("postgres", "CREATE INDEX ON tst USING hnsw (v sparsevec_l2_ops);");
+
+for (1 .. 3) {
+    for (1 .. 100) {
+        my @elements;
+        my %indices;
+        for (1 .. int(rand() * 100)) {
+            my $index = int(rand() * (100000 - 1)) + 1;
+            if (!exists($indices{$index})) {
+                my $value = rand();
+                push(@elements, "$index:$value");
+                $indices{$index} = 1;
+            }
+        }
+        my $embedding = "{" . join(",", @elements) . "}/100000";
+        $node->safe_psql("postgres", "INSERT INTO tst (v) VALUES ('$embedding');");
+    }
+
+    $node->safe_psql("postgres", "DELETE FROM tst WHERE i % 2 = 0;");
+    $node->safe_psql("postgres", "VACUUM tst;");
+    is(1, 1);
+}
+
+done_testing();