diff --git a/lib/pg_ha_migrations/relation.rb b/lib/pg_ha_migrations/relation.rb
index 4d4c077..c190046 100644
--- a/lib/pg_ha_migrations/relation.rb
+++ b/lib/pg_ha_migrations/relation.rb
@@ -107,7 +107,7 @@ def self.from_table_and_columns(table, columns)
       # modified from https://github.com/rails/rails/pull/47753
       if name.bytesize > MAX_NAME_SIZE
         hashed_identifier = "_#{OpenSSL::Digest::SHA256.hexdigest(name).first(10)}"
-        description = name.sub("index_#{table.name}_on", "ix_on")
+        description = name.sub("index_#{table.name}_on", "idx_on")
 
         short_limit = MAX_NAME_SIZE - hashed_identifier.bytesize
         short_description = description.mb_chars.limit(short_limit).to_s
diff --git a/spec/safe_statements_spec.rb b/spec/safe_statements_spec.rb
index 82a8a86..644482a 100644
--- a/spec/safe_statements_spec.rb
+++ b/spec/safe_statements_spec.rb
@@ -1832,19 +1832,19 @@ def up
           end
 
           it "generates index name with hashed identifier when default child index name is too large" do
-            create_range_partitioned_table("x" * 43, migration_klass, with_partman: true)
+            create_range_partitioned_table("x" * 42, migration_klass, with_partman: true)
 
             test_migration = Class.new(migration_klass) do
               def up
-                safe_add_concurrent_partitioned_index "x" * 43, :updated_at
+                safe_add_concurrent_partitioned_index "x" * 42, :updated_at
               end
             end
 
             allow(ActiveRecord::Base.connection).to receive(:execute).and_call_original
 
             aggregate_failures do
-              expect(ActiveRecord::Base.connection).to receive(:execute).with(/CREATE INDEX "index_#{"x" * 43}_on_updated_at" ON ONLY/).once.ordered
-              expect(ActiveRecord::Base.connection).to receive(:execute).with(/CREATE INDEX CONCURRENTLY "ix_on_updated_at_\w{10}/).exactly(10).times.ordered
+              expect(ActiveRecord::Base.connection).to receive(:execute).with(/CREATE INDEX "index_#{"x" * 42}_on_updated_at" ON ONLY/).once.ordered
+              expect(ActiveRecord::Base.connection).to receive(:execute).with(/CREATE INDEX CONCURRENTLY "idx_on_updated_at_\w{10}/).exactly(10).times.ordered
               expect(ActiveRecord::Base.connection).to receive(:execute).with(/ALTER INDEX .+\nATTACH PARTITION/).exactly(10).times.ordered
             end