Oracle 12c: Inconsistency of Inline “with” functions
I was hoping that if inline “with” functions are in the query, so their results will be consistent with it (as operators), but unfortunately such functions returns also inconsistent results as...
View ArticleOracle 12c: behavior tests of the Inline functions, “Identities” and “defaults”
I have done several minitests: 1. SQL and PL/SQL engines: which functions will be executed if there are two functions with same name as in SQL, as in PL/SQL (like “USER”, LPAD/RPAD, etc..) - PL/SQL....
View Article12c: Little test of “TABLE ACCESS INMEMORY FULL” with count stopkey
The table has 9M rows: SQL> with function f return int is 2 begin 3 for r in (select value from v$mystat natural join v$statname where name like 'IM scan rows') loop 4 dbms_output.put_line(r.value);...
View Article12c: New SQL PLAN OPERATIONS and HINTS
This post is just a compilation of the links to other people’s articles and short descriptions about new SQL PLAN OPERATIONS and HINTS with a couple little additions from me. th.c_operation_name {...
View ArticleHow to speed up slow unicode migration of a table with xmltype columns
Recently I have had an issue with slow unicode migration of the database upgraded from 10g to 12.1.0.2. The main problem was a table with xmltype: we spent about 4 hours for this table(~17GB) during...
View ArticleAdaptive serial direct path read decision ignores object statistics since 12.1
On versions 11.2.0.2 – 11.2.0.4 Oracle uses objects’ statistics to make direct path reads decision (of course, if “_direct_read_decision_statistics_driven” haven’t changed it to “false”), and we can...
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