Add max_locks_per_transaction config option

Signed-off-by: Marcelo Henrique Neppel <[email protected]>

config.yaml

@@ -17,6 +17,14 @@ options:
       “pg_catalog.english”.
     type: string
     default: "pg_catalog.simple"
+  instance_max_locks_per_transaction:
+    description: |
+      Specifies the maximum amount of memory to be used by maintenance operations,
+      such as "VACUUM", "CREATE INDEX", and "ALTER TABLE ADD FOREIGN KEY".
+      If this value is specified without units, it is taken as kilobytes.
+      Allowed values are: from 64 to 2147483647.
+    type: int
+    default: 65536
   instance_password_encryption:
     description: |
       Determines the algorithm to use to encrypt the password.

src/config.py

@@ -18,6 +18,7 @@ class CharmConfig(BaseConfigModel):
 
     durability_synchronous_commit: Optional[str]
     instance_default_text_search_config: Optional[str]
+    instance_max_locks_per_transaction: Optional[int]
     instance_password_encryption: Optional[str]
     logging_log_connections: Optional[bool]
     logging_log_disconnections: Optional[bool]
@@ -129,6 +130,15 @@ def instance_password_encryption_values(cls, value: str) -> Optional[str]:
 
         return value
 
+    @validator("instance_max_locks_per_transaction")
+    @classmethod
+    def instance_max_locks_per_transaction_values(cls, value: int) -> Optional[int]:
+        """Check instance_max_locks_per_transaction config option is between 64 and 2147483647."""
+        if value < 64 or value > 2147483647:
+            raise ValueError("Value is not between 64 and 2147483647")
+
+        return value
+
     @validator("logging_log_min_duration_statement")
     @classmethod
     def logging_log_min_duration_statement_values(cls, value: int) -> Optional[int]: