[MySQL] Fix missing innodb metrics for MySQL 5.6 & 5.7 (#18904)

* add mocked tests for innodb status parsing

* fix missing innodb metrics pending_log_writes, pending_checkpoint_writes, history_list_length

* add changelog

* remove print

mysql/changelog.d/18904.fixed

@@ -0,0 +1,5 @@
+Fixes missing innodb metrics collected from `SHOW ENGINE INNODB STATUS` output.
+- `mysql.innodb.history_list_length` for MySQL 5.6
+- `mysq..innodb.pending_log_writes` for MySQL 5.7
+- `mysql.innodb.pending_checkpoint_writes` for MySQL 5.7
+

mysql/datadog_checks/mysql/innodb_metrics.py

@@ -79,6 +79,7 @@ def get_stats_from_innodb_status(self, db):
 
             # SEMAPHORES
             if line.find('Mutex spin waits') == 0:
+                # MySQL 5.6 & 5.7 only
                 # Mutex spin waits 79626940, rounds 157459864, OS waits 698719
                 # Mutex spin waits 0, rounds 247280272495, OS waits 316513438
                 results['Innodb_mutex_spin_waits'] = int(row[3])
@@ -116,8 +117,13 @@ def get_stats_from_innodb_status(self, db):
                 # Trx id counter 861B144C
                 txn_seen = True
             elif line.find('History list length') == 0:
+                # MySQL 5.7 and above
                 # History list length 132
                 results['Innodb_history_list_length'] = int(row[3])
+            elif line.find('idle History list length') == 0:
+                # MySQL 5.6 only
+                # idle History list length 123
+                results['Innodb_history_list_length'] += int(row[4])
             elif txn_seen and line.find('---TRANSACTION') == 0:
                 # ---TRANSACTION 0, not started, process no 13510, OS thread id 1170446656
                 results['Innodb_current_transactions'] += 1
@@ -257,9 +263,15 @@ def get_stats_from_innodb_status(self, db):
                 # syncs, 2980893 checkpoints
                 results['Innodb_log_writes'] = int(row[0])
             elif line.find(" pending log writes, ") > 0:
+                # MySQL 5.6 only
                 # 0 pending log writes, 0 pending chkp writes
                 results['Innodb_pending_log_writes'] = int(row[0])
                 results['Innodb_pending_checkpoint_writes'] = int(row[4])
+            elif line.find(" pending log flushes, ") > 0:
+                # MySQL 5.7 only
+                # 0 pending log flushes, 0 pending chkp writes
+                results['Innodb_pending_log_writes'] = int(row[0])
+                results['Innodb_pending_checkpoint_writes'] = int(row[4])
             elif line.find("Log sequence number") == 0:
                 # This number is NOT printed in hex in InnoDB plugin.
                 # Log sequence number 272588624

mysql/metadata.csv

@@ -75,16 +75,16 @@ mysql.innodb.lsn_current,gauge,,,,Log sequence number as shown in the LOG sectio
 mysql.innodb.lsn_flushed,gauge,,,,Flushed up to log sequence number as shown in the LOG section of the SHOW ENGINE INNODB STATUS output.,0,mysql,mysql innodb lsn_flushed,
 mysql.innodb.lsn_last_checkpoint,gauge,,,,Log sequence number last checkpoint as shown in the LOG section of the SHOW ENGINE INNODB STATUS output.,0,mysql,mysql innodb lsn_last_checkpoint,
 mysql.innodb.mem_adaptive_hash,gauge,,byte,,As shown in the BUFFER POOL AND MEMORY section of the SHOW ENGINE INNODB STATUS output.,0,mysql,mysql innodb mem_adaptive_hash,
-mysql.innodb.mem_additional_pool,gauge,,byte,,As shown in the BUFFER POOL AND MEMORY section of the SHOW ENGINE INNODB STATUS output.,0,mysql,mysql innodb mem_additional_total,
+mysql.innodb.mem_additional_pool,gauge,,byte,,As shown in the BUFFER POOL AND MEMORY section of the SHOW ENGINE INNODB STATUS output. Only available in MySQL 5.6.,0,mysql,mysql innodb mem_additional_total,
 mysql.innodb.mem_dictionary,gauge,,byte,,As shown in the BUFFER POOL AND MEMORY section of the SHOW ENGINE INNODB STATUS output.,0,mysql,mysql innodb mem_dictionary,
 mysql.innodb.mem_file_system,gauge,,,,As shown in the BUFFER POOL AND MEMORY section of the SHOW ENGINE INNODB STATUS output.,0,mysql,mysql innodb mem filesystem,
 mysql.innodb.mem_lock_system,gauge,,,,As shown in the BUFFER POOL AND MEMORY section of the SHOW ENGINE INNODB STATUS output.,0,mysql,mysql innodb mem locksystem,
 mysql.innodb.mem_page_hash,gauge,,,,As shown in the BUFFER POOL AND MEMORY section of the SHOW ENGINE INNODB STATUS output.,0,mysql,mysql innodb mem page hash,
 mysql.innodb.mem_recovery_system,gauge,,,,As shown in the BUFFER POOL AND MEMORY section of the SHOW ENGINE INNODB STATUS output.,0,mysql,mysql innodb mem recovery system,
 mysql.innodb.mem_total,gauge,,byte,,As shown in the BUFFER POOL AND MEMORY section of the SHOW ENGINE INNODB STATUS output.,0,mysql,mysql innodb mem_total,memory
-mysql.innodb.mutex_os_waits,gauge,,event,second,The rate of mutex OS waits.,0,mysql,mutex os waits,
-mysql.innodb.mutex_spin_rounds,gauge,,event,second,The rate of mutex spin rounds.,0,mysql,mutex spin rounds,
-mysql.innodb.mutex_spin_waits,gauge,,event,second,The rate of mutex spin waits.,0,mysql,mutex spin waits,
+mysql.innodb.mutex_os_waits,gauge,,event,second,The rate of mutex OS waits. Only available in MySQL 5.6 and 5.7.,0,mysql,mysql innodb mutex os waits,
+mysql.innodb.mutex_spin_rounds,gauge,,event,second,The rate of mutex spin rounds. Only available in MySQL 5.6 and 5.7.,0,mysql,mutex spin rounds,
+mysql.innodb.mutex_spin_waits,gauge,,event,second,The rate of mutex spin waits. Only available in MySQL 5.6 and 5.7.,0,mysql,mutex spin waits,
 mysql.innodb.os_file_fsyncs,gauge,,operation,,(Delta) The total number of fsync() operations performed by InnoDB.,0,mysql,mysql innodb os file fsyncs,
 mysql.innodb.os_file_reads,gauge,,operation,,(Delta) The total number of files reads performed by read threads within InnoDB.,0,mysql,mysql innodb os file reads,
 mysql.innodb.os_file_writes,gauge,,operation,,(Delta) The total number of file writes performed by write threads within InnoDB.,0,mysql,mysql innodb os file writes,
@@ -100,8 +100,8 @@ mysql.innodb.pending_aio_sync_ios,gauge,,,,As shown in the FILE I/O section of t
 mysql.innodb.pending_buffer_pool_flushes,gauge,,flush,,As shown in the FILE I/O section of the SHOW ENGINE INNODB STATUS output.,0,mysql,mysql innodb buffer flushes,
 mysql.innodb.pending_checkpoint_writes,gauge,,,,As shown in the FILE I/O section of the SHOW ENGINE INNODB STATUS output.,0,mysql,,
 mysql.innodb.pending_ibuf_aio_reads,gauge,,,,As shown in the FILE I/O section of the SHOW ENGINE INNODB STATUS output.,0,mysql,mysql innodb aio reads,
-mysql.innodb.pending_log_flushes,gauge,,flush,,As shown in the FILE I/O section of the SHOW ENGINE INNODB STATUS output.,0,mysql,mysql innodb log flush,
-mysql.innodb.pending_log_writes,gauge,,write,,As shown in the FILE I/O section of the SHOW ENGINE INNODB STATUS output.,0,mysql,mysql innodb log write,
+mysql.innodb.pending_log_flushes,gauge,,flush,,As shown in the FILE I/O section of the SHOW ENGINE INNODB STATUS output. Only available in MySQL 5.6 and 5.7.,0,mysql,mysql innodb log flush,
+mysql.innodb.pending_log_writes,gauge,,write,,As shown in the FILE I/O section of the SHOW ENGINE INNODB STATUS output. Only available in MySQL 5.6 and 5.7.,0,mysql,mysql innodb log write,
 mysql.innodb.pending_normal_aio_reads,gauge,,read,,As shown in the FILE I/O section of the SHOW ENGINE INNODB STATUS output.,0,mysql,mysql innodb aio read,
 mysql.innodb.pending_normal_aio_writes,gauge,,write,,As shown in the FILE I/O section of the SHOW ENGINE INNODB STATUS output.,0,mysql,mysql aio write,
 mysql.innodb.queries_inside,gauge,,query,,As shown in the FILE I/O section of the SHOW ENGINE INNODB STATUS output.,0,mysql,mysql innodb queries inside,