Summary
This update improves SQL Server 2014 and SQL Server 2016 support for troubleshooting latency issues in AlwaysOn availability groups.
More Information
This update adds the following new AlwaysOn extended events:
- recovery_unit_harden_log_timestamps
- log_block_pushed_to_logpool
- hadr_log_block_compression
- hadr_log_block_decompression
- hadr_transport_receive_log_block_message
- hadr_log_block_group_commit
- hadr_capture_filestream_wait
- hadr_lsn_send_complete
- hadr_receive_harden_lsn_message
It also changes the following existing extended events:
- log_flush_start
- log_flush_complete
- hadr_apply_log_block
- hadr_capture_log_block
- hadr_capture_vlfheader
- hadr_log_block_send_complete
- hadr_send_harden_lsn_message
- ucs_connection_send_msg
This update introduces the following new performance counters:
| Counter | Comment |
|---|---|
| RedZones/sec | The number of log blocks RedZone in the last second to catch up the database replica. |
| Group Commit Time | Number of microseconds all transactions group commit waited. |
| Group Commits/Sec | Number of times transactions waited for group commit. |
| Log Bytes Compressed/sec | The amount of log in bytes compressed per sec. |
| Log Compressions/sec | The number of log blocks compressed per sec. |
| Log Compression Cache misses/sec | The number of log block compression cache misses per sec. |
| Log Compression Cache hits/sec | The number of log block compression hits per sec. |
| Log Bytes Decompressed/sec | The amount of log in bytes decompressed per sec. |
| Log Decompressions/sec | The number of log blocks decompressed per sec. |
| Database Flow Control Delay | Duration spent in database flow control wait. |
| Database Flow Controls/sec | The number of database flow control per sec. |
| Encryption I/Os/sec | The number of transport encrypted I/Os per second. Be aware that a transport send I/O may contain more than one message fragment. |
| Encrypted I/O bytes/sec | The number of transport encrypted I/O bytes per second. |
| Decryption I/Os/sec | The number of transport decrypted I/Os per second. You should be aware that a transport send I/O may contain more than one message fragment. |
| Decrypted I/O bytes/sec | The number of transport decrypted I/O bytes per second. |
| Send Flow Control Gate | UCS send boxcars pending on flow control gate exit. |
| Send Flow Control Enters/sec | UCS send flow control enters per sec. |
| Send Flow Control Exits/sec | UCS send flow control exists per sec. |
| Receive Flow Control Gate | UCS receive messages pending on flow control gate exit. |
| Receive Flow Control Enters/sec | UCS receive flow control enters per sec. |
| Receive Flow Control Exits/sec | UCS send flow control exits per sec. |
This update is included in the following service pack for SQL Server:
SQL Server 2014 Service Pack 2
SQL Server 2016 Service Pack 1
About service packs for SQL Server
Service packs are cumulative. Each new service pack contains all the fixes that are in previous service packs, together with any new fixes. Our recommendation is to apply the latest service pack and the latest cumulative update for that service pack. You do not have to install a previous service pack before you install the latest service pack. Use Table 1 in the following article for finding more information about the latest service pack and latest cumulative update.
How to determine the version, edition, and update level of SQL Server and its components
References
Learn about the terminology that Microsoft uses to describe software updates.