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TB054 Performance of Masking Jobs May Degrade or Introduce Inconsistent Results



This article applies to the following versions of the Delphix Masking Engine:

Major Release

All Sub Releases




Alert Type

Performance, Functional


In affected software releases, tables to be masked may incorrectly be masked multiple times, one time for each configured masking stream.   This can lead to significant decreases in masking job performance and inconsistent results as a result of multiple-passes of masking algorithms being applied.   

Additionally, despite being configured to run with multiple masking streams in parallel, affected configurations will instead run streams serially, further impacting performance.

Inconsistent results of masking can lead to referential integrity issues in masked databases. Masked results could be non-deterministic, with different results occurring even with identically-configured jobs and algorithms.

Contributing Factors

Masking jobs that have more than one stream configured are impacted. The number of streams configured dictates the number of tables that can be processed simultaneously during a masking job.

The impact severity may increase with larger numbers of concurrent streams.


Masking jobs may take longer to complete, especially when compared to identically-configured masking jobs running under prior, non-impacted,  Delphix software releases.

Masked data results may not match those from prior runs, even when the same masking options and algorithms are selected.


Configure only a single stream by configuring a 1 in the No. of Streams field of a masking job.   This will prevent pathological performance that may be seen with high values for concurrency. It will also eliminate the possibility of inconsistent masking results and the associated risk of referential integrity problems.

This should be considered a temporary measure. Once an official fix is available the configuration should be reverted to use a concurrency level that optimizes performance.


This issue is fully resolved in Delphix Release, and later releases. 

Additional Information





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