perf(InvoiceGeneration) - add index on invoices to speed up fetching …

…the highest organization_sequential_id (#3146)

## description

This index reduces the time to fetch the highest id from around 40ms to
0.4ms.

app/models/invoice.rb

@@ -517,16 +517,17 @@ def status_changed_to_finalized?
 #
 # Indexes
 #
-#  index_invoices_on_customer_id                    (customer_id)
-#  index_invoices_on_customer_id_and_sequential_id  (customer_id,sequential_id) UNIQUE
-#  index_invoices_on_issuing_date                   (issuing_date)
-#  index_invoices_on_number                         (number)
-#  index_invoices_on_organization_id                (organization_id)
-#  index_invoices_on_payment_overdue                (payment_overdue)
-#  index_invoices_on_ready_to_be_refreshed          (ready_to_be_refreshed) WHERE (ready_to_be_refreshed = true)
-#  index_invoices_on_self_billed                    (self_billed)
-#  index_invoices_on_sequential_id                  (sequential_id)
-#  index_invoices_on_status                         (status)
+#  idx_on_organization_id_organization_sequential_id_2387146f54  (organization_id,organization_sequential_id DESC)
+#  index_invoices_on_customer_id                                 (customer_id)
+#  index_invoices_on_customer_id_and_sequential_id               (customer_id,sequential_id) UNIQUE
+#  index_invoices_on_issuing_date                                (issuing_date)
+#  index_invoices_on_number                                      (number)
+#  index_invoices_on_organization_id                             (organization_id)
+#  index_invoices_on_payment_overdue                             (payment_overdue)
+#  index_invoices_on_ready_to_be_refreshed                       (ready_to_be_refreshed) WHERE (ready_to_be_refreshed = true)
+#  index_invoices_on_self_billed                                 (self_billed)
+#  index_invoices_on_sequential_id                               (sequential_id)
+#  index_invoices_on_status                                      (status)
 #
 # Foreign Keys
 #

db/migrate/20250205184611_add_index_on_invoices_org_seq_id.rb

@@ -0,0 +1,13 @@
+# frozen_string_literal: true
+
+class AddIndexOnInvoicesOrgSeqId < ActiveRecord::Migration[7.1]
+  disable_ddl_transaction!
+
+  def change
+    add_index :invoices, [:organization_id, :organization_sequential_id],
+      order: {organization_sequential_id: :desc},
+      algorithm: :concurrently,
+      if_not_exists: true,
+      include: %i[self_billed]
+  end
+end