Apr-14

24-Apr

 HAIP  – 11gR2

http://orainternals.files.wordpress.com/2012/04/2012_326_riyaj_scan_vip_haip_doc.pdf

 23-Apr

 Exadata Flashcache X4 Family

http://www.oracle.com/technetwork/database/exadata/exadata-smart-flash-cache-366203.pdf

Configure hugepages dynamically in Linux

# grep Huge /proc/meminfo

Update vm.nr_hugepages to required value in /etc/sysctl.conf and run sysctl as root to effect the new values

#sysctl -p

Exadata X4 storage configurations

http://www.oracle.com/technetwork/database/exadata/exadata-storage-technical-overview-128045.pdf

22-Apr

 Huge pages information is at: /sys/kernel/mm/hugepages

You can see there – Transparent Hugepages configured or not.

21-Apr

 Configuring jumbo frames for RAC interface

https://blogs.oracle.com/XPSONHA/entry/jumbo_frames_for_rac_interconn_1

To get interface page table –

netstat –i

MAA and backup – On Exadata machine

http://www.oracle.com/au/products/database/maa-tech-wp-sundbm-backup-11202-183503.pdf

 07-Apr

 To get total RAM in Linux

dmesg | grep RAM

04-Apr

 Exadata WriteThrough and buffer busy waits

http://guyharrison.squarespace.com/blog/2013/11/22/exadata-write-back-cache-and-free-buffer-waits.html

Setting CELL_FLASH_CACHE to KEEP for table shoots up time for the first time FTS and subsequent FTS will be faster.  So, remember to enable KEEP to pin a tbale in FLASHCACHE only if multiple scans are expected for a table.  The blogger is not clearly states the reasons for this extra time spent.  I believe this is the extra  time spend to cache the blocks in FLASHCACHE before sending the blocks to the buffer cache, but not sure.

http://guyharrison.squarespace.com/blog/2013/12/30/can-the-exadata-smart-flash-cache-slow-smart-scans.html

Switching between Writeback and Writethrouh –

<pre>CellCli> drop flashcache
 CellCLI> alter cell shutdown services cellsrv
 CellCLI> alter cell flashCacheMode = WriteBack
 CellCLI> alter cell startup services cellsrv
 CellCLI> create flashcache all
 

CellCLI> alter flashcache all flush
 CellCLI> drop flashcache
 CellCLI> alter cell shutdown services cellsrv
 CellCLI> alter cell flashCacheMode=Writethrough
 CellCLI> alter cell startup services cellsrv

http://sbhoracle.wordpress.com/2013/05/21/exadata-smart-flash-cache-a-note-of-understanding/

03-Apr

DBA_HIST_SEG_STAT captures the segment level statistics for heavily used segments.

http://docs.oracle.com/cd/E18283_01/server.112/e17110/statviews_4031.htm

ITL blocks history can be obtained from the DBA_HIST_SEG_STAT, see what Arup says

http://arup.blogspot.in/2011/01/more-on-interested-transaction-lists.html

02-April

LOG_BUFFER size can vary from 8MB to 256MB.  If ASYNC  log transport is configure, it is better to keep log_buffer 128MB or above to enable ‘in memory log’ hits for log transport.  See the note: 951152.1.  See the view x$logbuf_readhist.

<pre>select BUFSIZE, RDMEMBLKS, RDDISKBLKS, HITRATE, BUFINFO  from X$LOGBUF_READHIST;

LOG_BUFFER configuration from oracle documentation: http://docs.oracle.com/cd/E11882_01/server.112/e10803/config_db.htm#HABPT4836

About exadata storage indexes, by Arup :

http://www.oracle.com/technetwork/issue-archive/2011/11-may/o31exadata-354069.html

Oracle Exadata storage indexes intelligence is built into the CELL server to prune the data and reduce the physical I/O.  SI is an In Memory data structure.  For every 1MB data, the maximum and minimum column values for up to 8 columns are stored in storage indexes.  The block will be read by the Cell server only if the column data found in the index.  Placement of a column is automatically identified by the server based on the WHERE clause predicate.    See test cases

http://www.oaktable.net/blog/when-exadata%E2%80%99s-storage-indexes-used

Kerry talks about Exadata offloading – a good one

http://kerryosborne.oracle-guy.com/2010/06/exadata-offload-the-secret-sauce/#more-2531

Some facts about CELL performance

http://blog.tanelpoder.com/files/Tanel_Poder_Drilling_Deep_Into_Exadata_Performance.pdf

Various  Latches and locks

http://dbatrain.wordpress.com/page/2/

Good presentations

http://dbatrain.wordpress.com/articles-papers-and-presentations/

  1. No comments yet.
  1. No trackbacks yet.

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s

%d bloggers like this: