diff --git a/app/helpers/pg_hero/home_helper.rb b/app/helpers/pg_hero/home_helper.rb
index 6caa2d4c4..00f766c41 100644
--- a/app/helpers/pg_hero/home_helper.rb
+++ b/app/helpers/pg_hero/home_helper.rb
@@ -5,7 +5,7 @@ def pghero_pretty_ident(table, schema: nil)
       if schema && schema != "public"
         ident = "#{schema}.#{table}"
       end
-      if ident =~ /\A[a-z0-9_]+\z/
+      if /\A[a-z0-9_]+\z/.match?(ident)
         ident
       else
         @database.quote_ident(ident)
diff --git a/lib/pghero/database.rb b/lib/pghero/database.rb
index fa03e89be..2b70dd853 100644
--- a/lib/pghero/database.rb
+++ b/lib/pghero/database.rb
@@ -126,7 +126,7 @@ def connection_model
         # rough check for Postgres adapter
         # keep this message generic so it's useful
         # when empty url set in Docker image pghero.yml
-        unless @connection_model.connection.adapter_name =~ /postg/i
+        unless @connection_model.connection.adapter_name.match?(/postg/i)
           raise Error, "Invalid connection URL"
         end
         @adapter_checked = true
diff --git a/lib/pghero/methods/explain.rb b/lib/pghero/methods/explain.rb
index f997eeddc..7189667a5 100644
--- a/lib/pghero/methods/explain.rb
+++ b/lib/pghero/methods/explain.rb
@@ -9,7 +9,7 @@ def explain(sql)
 
         # use transaction for safety
         with_transaction(statement_timeout: (explain_timeout_sec * 1000).round, rollback: true) do
-          if (sql.sub(/;\z/, "").include?(";") || sql.upcase.include?("COMMIT")) && !explain_safe?
+          if (sql.delete_suffix(";").include?(";") || sql.upcase.include?("COMMIT")) && !explain_safe?
             raise ActiveRecord::StatementInvalid, "Unsafe statement"
           end
           explanation = execute("EXPLAIN #{sql}").map { |v| v["QUERY PLAN"] }.join("\n")
diff --git a/lib/pghero/methods/query_stats.rb b/lib/pghero/methods/query_stats.rb
index 03c6d5cc7..ab83f9c87 100644
--- a/lib/pghero/methods/query_stats.rb
+++ b/lib/pghero/methods/query_stats.rb
@@ -322,7 +322,7 @@ def combine_query_stats(grouped_stats)
             all_queries_total_minutes: stats2.sum { |s| s[:all_queries_total_minutes] }
           }
           value[:total_percent] = value[:total_minutes] * 100.0 / value[:all_queries_total_minutes]
-          value[:explainable_query] = stats2.map { |s| s[:explainable_query] }.select { |q| q && explainable?(q) }.first
+          value[:explainable_query] = stats2.map { |s| s[:explainable_query] }.find { |q| q && explainable?(q) }
           query_stats << value
         end
         query_stats
diff --git a/lib/pghero/methods/suggested_indexes.rb b/lib/pghero/methods/suggested_indexes.rb
index 26431850d..9d17560e2 100644
--- a/lib/pghero/methods/suggested_indexes.rb
+++ b/lib/pghero/methods/suggested_indexes.rb
@@ -46,7 +46,7 @@ def suggested_indexes_by_query(queries: nil, query_stats: nil, indexes: nil)
                   indexes += existing_columns["brin"][index[:table]]
                 end
 
-                covering_index = indexes.find { |e| index_covers?(e.map { |v| v.sub(/ inet_ops\z/, "") }, index[:columns]) }
+                covering_index = indexes.find { |e| index_covers?(e.map { |v| v.delete_suffix(" inet_ops") }, index[:columns]) }
                 if covering_index
                   best_index[:covering_index] = covering_index
                   best_index[:explanation] = "Covered by index on (#{covering_index.join(", ")})"
diff --git a/lib/pghero/methods/system.rb b/lib/pghero/methods/system.rb
index 556ff0ea5..92ed19424 100644
--- a/lib/pghero/methods/system.rb
+++ b/lib/pghero/methods/system.rb
@@ -136,8 +136,8 @@ def gcp_stats(metric_name, duration: nil, period: nil, offset: nil, series: fals
         start_time = end_time - duration
 
         # validate input since we need to interpolate below
-        raise Error, "Invalid metric name" unless metric_name =~ /\A[a-z\/_]+\z/i
-        raise Error, "Invalid database id" unless gcp_database_id =~ /\A[a-z0-9\-:]+\z/i
+        raise Error, "Invalid metric name" unless /\A[a-z\/_]+\z/i.match?(metric_name)
+        raise Error, "Invalid database id" unless /\A[a-z0-9\-:]+\z/i.match?(gcp_database_id)
 
         # we handle four situations:
         # 1. google-cloud-monitoring-v3