Bahvior Change

Network ACLs and Database Upgrade to Oracle 12c

What has been changed in Oracle Database 12c with Network ACLs?

Starting from 12c, network access control in the Oracle database is implemented using Real Application Security access control lists (ACLs). Existing 11g network ACLs in XDB will be migrated. Existing procedures and functions of the DBMS_NETWORK_ACL_ADMIN PL/SQL package and catalog views have been deprecated and replaced with new equivalents

In 12c, a network privilege can be granted by appending an access control entry (ACE) to a host ACL using DBMS_NETWORK_ACL_ADMIN.APPEND_HOST_ACE.  If you append an ACE to a host that has no existing host ACL, a new …

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UPDATE: _rowsets_enabled in Oracle Database 12c

Please find a recent update here:

Last week I did post this entry with a strong recommendation to disable _rowsets_enabled in Oracle Database

Today I can give you an update, more insight information and better workarounds.

Credits go to our DWH and Optimizer people (thanks to Hermann, Angela, Nigel and Mohammed).

When is the problem happening?

When a hash join operation receives rowsets from its right input but then produces one row at a time as output. This explains …

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Where do these large trace files come from in Oracle 12c?

Just had an observation about very large trace files on one of my customers I’m working with at the moment. When I write “very” I mean “VERY” as some grew over 10GB within a few hours.

Growth - Trace Files - (c) Mike Dietrich

The files contained a ton of such messages:

----- Cursor Obsoletion Dump sql_id=5p8a9d4017bq3 -----
Parent cursor obsoleted 1 time(s). maxchild=1024 basephd=00007FFB8AD45CB0 phd=00007FFB8AD45CB0

After doing a bit of research I came across this document and an explanation:

MOS Note:1955319.1;
Huge Trace Files Created Containing “—– Cursor Obsoletion Dump sql_id=%s —–“

Well, we introduced an Enhancement – via an unpublished bug (and I’d guess it is …

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