Handle >64 characters partition names

dbt/include/postgres/macros/adapters.sql

@@ -44,8 +44,7 @@
                   date_trunc('{{ partition_by_granularity }}', min({{ partition_by_field }})),
                   date_trunc('{{ partition_by_granularity }}', max({{ partition_by_field }})),
                   '1 {{ partition_by_granularity }}'::interval
-              ) as begin_date,
-              (select floor(random() * 100 + 1)::int) as rand -- Random number to avoid name colissions
+              ) as begin_date
           from (
             {{ sql }}
           ) model_subq
@@ -109,19 +108,17 @@
     {% set existing_partitions_query %}
       select
         inhrelid::regclass::text as from_table_name,
-        replace(
-          inhrelid::regclass::text,
-          '{{ from_relation.schema }}.{{ from_relation.identifier }}', -- Current partition name
-          '{{ to_relation.identifier }}' -- New partition name
-        ) as to_table_name
+        regexp_substr(inhrelid::regclass::text, '[^_]*$') as partition_suffix -- Get the string after the last underscore
       from pg_catalog.pg_inherits
       where inhparent = '{{ from_relation.schema }}.{{ from_relation.identifier }}'::regclass;
     {% endset %}
     {% set existing_partitions_results = run_query(existing_partitions_query) %}
 
     -- Rename the existing partitions
     {% for existing_partition in existing_partitions_results.rows %}
-      alter table {{ existing_partition["from_table_name"] }} rename to {{ existing_partition["to_table_name"] }};
+      {%- set partition_relation = make_intermediate_relation(to_relation, existing_partition['partition_suffix']) %}
+
+      alter table {{ existing_partition["from_table_name"] }} rename to {{ partition_relation.identifier }};
     {% endfor %}
   {%- endcall %}
 {% endmacro %}