Pass query_signature down into explain_statement

No need to recalculate this, and passing it down will allow trimmed SQL
to reuse the original query's signature.

Author: jasonmp85

postgres/datadog_checks/postgres/explain_parameterized_queries.py

@@ -7,7 +7,6 @@
 
 import psycopg2
 
-from datadog_checks.base.utils.db.sql import compute_sql_signature
 from datadog_checks.base.utils.tracking import tracked_method
 from datadog_checks.postgres.cursor import CommenterDictCursor
 
@@ -73,7 +72,7 @@ def __init__(self, check, config, explain_function):
         self._explain_function = explain_function
 
     @tracked_method(agent_check_getter=agent_check_getter)
-    def explain_statement(self, dbname, statement, obfuscated_statement):
+    def explain_statement(self, dbname, statement, obfuscated_statement, query_signature):
         if self._check.version < V12:
             # if pg version < 12, skip explaining parameterized queries because
             # plan_cache_mode is not supported
@@ -85,7 +84,6 @@ def explain_statement(self, dbname, statement, obfuscated_statement):
             return None, DBExplainError.parameterized_query, '{}'.format(type(e))
         self._set_plan_cache_mode(dbname)
 
-        query_signature = compute_sql_signature(obfuscated_statement)
         try:
             self._create_prepared_statement(dbname, statement, obfuscated_statement, query_signature)
         except psycopg2.errors.IndeterminateDatatype as e:

postgres/datadog_checks/postgres/statement_samples.py

@@ -786,7 +786,7 @@ def _run_explain_safe(self, dbname, statement, obfuscated_statement, query_signa
             if self._explain_parameterized_queries._is_parameterized_query(statement):
                 if is_affirmative(self._config.statement_samples_config.get('explain_parameterized_queries', True)):
                     return self._explain_parameterized_queries.explain_statement(
-                        dbname, statement, obfuscated_statement
+                        dbname, statement, obfuscated_statement, query_signature
                     )
                 e = psycopg2.errors.UndefinedParameter("Unable to explain parameterized query")
                 self._log.debug(

postgres/tests/test_explain_parameterized_queries.py

@@ -51,7 +51,9 @@ def test_explain_parameterized_queries(integration_check, dbm_instance, query, e
     if check.version < V12:
         return
 
-    plan_dict, explain_err_code, err = check.statement_samples._run_and_track_explain(DB_NAME, query, query, query)
+    plan_dict, explain_err_code, err = check.statement_samples._run_and_track_explain(
+        DB_NAME, query, query, "7231596c8b5536d1"
+    )
     assert plan_dict is not None
     assert explain_err_code == expected_explain_err_code
     assert err is None
@@ -111,7 +113,10 @@ def test_explain_parameterized_queries_version_below_12(integration_check, dbm_i
         return
 
     plan_dict, explain_err_code, err = check.statement_samples._run_and_track_explain(
-        DB_NAME, "SELECT * FROM pg_settings WHERE name = $1", "SELECT * FROM pg_settings WHERE name = $1", ""
+        DB_NAME,
+        "SELECT * FROM pg_settings WHERE name = $1",
+        "SELECT * FROM pg_settings WHERE name = $1",
+        "7231596c8b5536d1",
     )
     assert plan_dict is None
     assert explain_err_code == DBExplainError.parameterized_query
@@ -133,7 +138,10 @@ def test_explain_parameterized_queries_create_prepared_statement_exception(integ
         side_effect=psycopg2.errors.DatabaseError("unexpected exception"),
     ):
         plan_dict, explain_err_code, err = check.statement_samples._run_and_track_explain(
-            DB_NAME, "SELECT * FROM pg_settings WHERE name = $1", "SELECT * FROM pg_settings WHERE name = $1", ""
+            DB_NAME,
+            "SELECT * FROM pg_settings WHERE name = $1",
+            "SELECT * FROM pg_settings WHERE name = $1",
+            "7231596c8b5536d1",
         )
         assert plan_dict is None
         assert explain_err_code == DBExplainError.failed_to_explain_with_prepared_statement
@@ -155,7 +163,9 @@ def test_explain_parameterized_queries_explain_prepared_statement_exception(inte
         side_effect=psycopg2.errors.DatabaseError("unexpected exception"),
     ):
         query = "SELECT * FROM pg_settings WHERE name = $1"
-        plan_dict, explain_err_code, err = check.statement_samples._run_and_track_explain(DB_NAME, query, query, "")
+        plan_dict, explain_err_code, err = check.statement_samples._run_and_track_explain(
+            DB_NAME, query, query, "7231596c8b5536d1"
+        )
         assert plan_dict is None
         assert explain_err_code == DBExplainError.failed_to_explain_with_prepared_statement
         assert err is not None
@@ -184,7 +194,10 @@ def test_explain_parameterized_queries_explain_prepared_statement_no_plan_return
         return_value=None,
     ):
         plan_dict, explain_err_code, err = check.statement_samples._run_and_track_explain(
-            DB_NAME, "SELECT * FROM pg_settings WHERE name = $1", "SELECT * FROM pg_settings WHERE name = $1", ""
+            DB_NAME,
+            "SELECT * FROM pg_settings WHERE name = $1",
+            "SELECT * FROM pg_settings WHERE name = $1",
+            "7231596c8b5536d1",
         )
         assert plan_dict is None
         assert explain_err_code == DBExplainError.no_plan_returned_with_prepared_statement