Quanlong Huang has posted comments on this change. ( http://gerrit.cloudera.org:8080/16861 )
Change subject: IMPALA-10388: [DOCS] add limitations on mask functions ...................................................................... Patch Set 2: (1 comment) http://gerrit.cloudera.org:8080/#/c/16861/2/docs/topics/impala_authorization.xml File docs/topics/impala_authorization.xml: http://gerrit.cloudera.org:8080/#/c/16861/2/docs/topics/impala_authorization.xml@711 PS2, Line 711: <li>This example shows how to use the overload mask(FLOAT) that is not yet implemented in : Impala. If you want to mask float/double/decimal to NULLs, you can use a more efficient : Nullify policy (MASK_NULL) for the same purpose. Do not use Redact(MASK) on : float/double/decimal types as Hive always returns NULL for them since it is not : redact.</li> This is not an example "shows how to use the overload mask(FLOAT) that is not yet implemented in Impala"... What I want to say is mask(FLOAT), mask(DOUBLE), mask(DECIMAL) are missing in Impala currently. If users use Redact(MASK) column masking policy on float/double/decimal columns, they will hit an error like "No matching function with signature: mask..." in Impala. Then I explain that it doesn't make sense to use Redact(MASK) column masking policy on float/double/decimal columns. The reason is Hive's mask function always returns NULLs on these types. The actually meaning of "Redact" is replacing the content with mask characters, e.g. transforming "ABCDabcd-1234" to "XXXXxxxx-nnnn". So transforming 3.14 to NULL doesn't mean "Redact" actually. "Redact" will transform "3.14" to "n.nn". If users do want to mask float/double/decimal types to NULLs, they should use the Nullify policy. I think you understand this part correctly. :) The missing overloads are not just mask(FLOAT), mask(DOUBLE) and mask(DECIMAL). This is an example explaining why they are missing (because it doesn't make sense to use them), and providing a workaround if users do want to use them. I think if it's hard to explain these, we can remove this paragraph. -- To view, visit http://gerrit.cloudera.org:8080/16861 To unsubscribe, visit http://gerrit.cloudera.org:8080/settings Gerrit-Project: Impala-ASF Gerrit-Branch: master Gerrit-MessageType: comment Gerrit-Change-Id: I37f0bcf4cf586cc5cfd03e4df68443967b6bb88f Gerrit-Change-Number: 16861 Gerrit-PatchSet: 2 Gerrit-Owner: Shajini Thayasingh <sthayasi...@cloudera.com> Gerrit-Reviewer: Impala Public Jenkins <impala-public-jenk...@cloudera.com> Gerrit-Reviewer: Quanlong Huang <huangquanl...@gmail.com> Gerrit-Comment-Date: Fri, 18 Dec 2020 13:20:29 +0000 Gerrit-HasComments: Yes
