[DBMON-4818] Fix query for sql replica threads (#20172)

* Fix query for sql replica threads

* Add changelog

* Fix formatting

* Clarify changelog

* Remove unnecessary leading %

Author: eric-weaver

mysql/changelog.d/20172.fixed

@@ -0,0 +1 @@
+Fixes incorrect replica counts when querying from performance_schema.threads

mysql/datadog_checks/mysql/mysql.py

@@ -69,14 +69,14 @@
     SQL_GROUP_REPLICATION_METRICS_8_0_2,
     SQL_GROUP_REPLICATION_PLUGIN_STATUS,
     SQL_INNODB_ENGINES,
-    SQL_PROCESS_LIST,
     SQL_QUERY_SCHEMA_SIZE,
     SQL_QUERY_SYSTEM_TABLE_SIZE,
     SQL_QUERY_TABLE_ROWS_STATS,
     SQL_QUERY_TABLE_SIZE,
+    SQL_REPLICA_PROCESS_LIST,
+    SQL_REPLICA_WORKER_THREADS,
     SQL_REPLICATION_ROLE_AWS_AURORA,
     SQL_SERVER_ID_AWS_AURORA,
-    SQL_WORKER_THREADS,
     show_replica_status_query,
 )
 from .statement_samples import MySQLStatementSamples
@@ -1183,9 +1183,9 @@ def _get_replica_status(self, db, above_560, nonblocking):
                 if above_560 and nonblocking:
                     # Query `performance_schema.threads` instead of `
                     # information_schema.processlist` to avoid mutex impact on performance.
-                    cursor.execute(SQL_WORKER_THREADS)
+                    cursor.execute(SQL_REPLICA_WORKER_THREADS)
                 else:
-                    cursor.execute(SQL_PROCESS_LIST)
+                    cursor.execute(SQL_REPLICA_PROCESS_LIST)
                 replica_results = cursor.fetchall()
                 replicas = 0
                 for _ in replica_results:

mysql/datadog_checks/mysql/queries.py

@@ -41,9 +41,11 @@
 WHERE schema_name IS NOT NULL
 GROUP BY schema_name"""
 
-SQL_WORKER_THREADS = "SELECT THREAD_ID, NAME FROM performance_schema.threads WHERE NAME LIKE '%worker'"
+SQL_REPLICA_WORKER_THREADS = (
+    "SELECT THREAD_ID, NAME FROM performance_schema.threads WHERE PROCESSLIST_COMMAND LIKE 'Binlog dump%'"
+)
 
-SQL_PROCESS_LIST = "SELECT * FROM INFORMATION_SCHEMA.PROCESSLIST WHERE COMMAND LIKE '%Binlog dump%'"
+SQL_REPLICA_PROCESS_LIST = "SELECT * FROM INFORMATION_SCHEMA.PROCESSLIST WHERE COMMAND LIKE 'Binlog dump%'"
 
 SQL_INNODB_ENGINES = """\
 SELECT engine