Given this extract from an AWR :
Instance Efficiency Percentages (Target 100%)
Buffer Nowait %: 100.00 Redo NoWait %: 100.00
Buffer Hit %: 99.93 In-memory Sort %: 100.00
Library Hit %: 94.76 Soft Parse %: 96.21
Execute to Parse %: 30.63 Latch Hit %: 100.00
Parse CPU to Parse Elapsd %: 79.13 % Non-Parse CPU: 93.52
Should I be worried about the Parse ratios ?
Occasionally, we come across questions about multiple channels and parallelism in RMAN.
Although RMAN distributes the datafiles across the channels, it doesn't necessarily mean that each channel has the same I/O requirements and needs the same amount of time. One channel may be reading more data and writing a larger backup than another.
For example, in this database with 16 datafiles where data is not equally distributed across all the datafiles :
SQL> select file_id, sum(blocks) from dba_extents group by file_id order by 1;
A few weeks ago, there was a question about disabling TRUNCATEs. That can be easily done via a Trigger.
SQL> -- create a trigger that raises an error on truncates
SQL> create or replace trigger prevent_truncates
2 before truncate on schema
4 raise_application_error(-20001,'TRUNCATE not permitted');
Here's a video by Stephane Faroult (RoughSea) : "Are you ready 2.0 ?"
A recent ComputerWorld article "How are students learning programming in a post-Basic world ?" (It should be BASIC, not Basic) reminds me of the time I first learnt programming.
Oracle ACEs in this part of the world had a conference call with Oracle's Program Executive for the APAC Developer Program.
A response recent forums question about handling an inequality condition also reminded me, once again, about NULL handling in Oracle.
You can have :
WHERE column = 100
in a query.
In another query, you could have
WHERE column != 100
However, if the column does contain a NULL in any one (or more rows), the union of the two queries is not the entire table. That is, rows with NULLs are excluded.
You have to specifically handle NULLs with either