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Author Archives Tanel Poder

List Exadata Storage Cell disk summary with cellpd.sql and cellpdx.sql scripts

In the previous post I explained how to list Exadata disk layout and topology details with the exadisktopo scripts, in this post I’ll introduce one celldisk overview script, which I use to quickly see the celldisk configuration, specs and error statuses. The cellpd.sql script (Cell Physical Disk) will show the following output: SQL> @exadata/cellpd.sql Show [...]

Posted 24 May 2013 § Oracle § Uncategorized ‡ Comments Off °

List Exadata Disk Layout and Topology with the exadisktopo scripts

Here are two more Exadata scripts for listing the end-to-end ASM<->Exadata disk topology from V$ASM_ views and from V$CELL_CONFIG. These scripts see both the ASM level layout and the storage cell-level disk topology. The exadisktopo.sql script shows all disks starting from the ASM diskgroup layer, going deeper and deeper all the way to the OS [...]

Posted 24 May 2013 § Oracle § Uncategorized ‡ Comments Off °

V$CELL_THREAD_HISTORY – “ASH” for Exadata Storage Cells

Did you know that there’s something like Active Session History also in the Exadata storage cells? ;-) The V$CELL_THREAD_HISTORY view is somewhat like V$ACTIVE_SESSION_HISTORY, but it’s measuring thread activity in the Exadata Storage Cells: SQL> @desc v$cell_thread_history Name Null? Type ——————————- ——– —————————- 1 CELL_NAME VARCHAR2(1024) 2 SNAPSHOT_ID NUMBER 3 SNAPSHOT_TIME DATE 4 THREAD_ID NUMBER [...]

Posted 23 May 2013 § Oracle § Uncategorized ‡ Comments Off °

Is this valid SQL syntax? :-)

I’m talking about this: select-1from from dual; Looks like invalid, right? Well, let’s run it: SQL> select-1from from dual;        ROM ———-  -1.0E+000 This is because: Oracle doesn’t need whitespace for tokenizing the SQL statement (differences in character classes will do – as I’ve explained here) The first from “keyword” in the above statement is [...]

Posted 10 January 2011 § Uncategorized ‡ Comments Off °

Quiz: Explaining index creation

Did you know that it’s possible to use EXPLAIN PLAN FOR CREATE INDEX ON table(col1,col2,col3) syntax for explaining what exactly would be done when an index is created? That’s useful for example for seeing the Oracle’s estimated index size without having to actually create the index. You can also use EXPLAIN PLAN FOR ALTER INDEX [...]

Posted 23 April 2010 § Uncategorized ‡ Comments Off °