SQL 2016 – It Just Runs Faster: AlwaysOn Parallel Compression / Improved Algorithms

SQL Server 2016 introduces two distinct changes in the AlwaysOn transport, compression design.


  1. Improved compression algorithms
  2. Parallel compression of log block data


Compression can be performed faster, using less resource overhead and maintains compression ratios.


SQL Server 2016 also introduces parallel compression operations.  The following chart outlines the performance and resource gains as tested using a TPCC stress load.



Throughput MB/s

Average CPU utilization (secondary)

MB sent on wire/sec










Since the primary's compressed buffers are shared among multiple secondary transports all secondary's must support the newer algorithms or the primary uses the SQL 2014 compression algorithms.


SQL Server 2016 always performances parallel decompression regardless of the compression algorithm chosen.


'It Just Runs Faster' - SQL Server 2016 combines new compression algorithms and parallelization to significantly improve AlwaysOn log transport capabilities.


Bob Dorr - Principal SQL Server Software Engineer

Zhengguo Sun

Nithin Mahesh

Fady Sedrak

Comments (2)
  1. Glenn Berry says:

    Is there any difference in this particular area between Basic Availability Groups (BAG) (in Standard Edition) and regular Availability Groups (in Enterprise Edition)? In other words, will you get parallel compression with BAGs?

    1. RDORR says:

      For the most part the AG logic for Standard (BAGs) is just to add the limitations for a single, non-readable replica. We tried to avoid additional code variations.

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