May-14
28-May
OS watcher location in Exadata (Linux)
$ cd /opt/oracle.oswatcher/osw
To see a compressed file
$ bzcat <file name> > head -10
SQL monitor details using DBMS_SQLTUNE
set pagesize 0 echo on timing off set linesize 200 trimspool on trim on set long 2000000 longchunksize 2000000 select DBMS_SQLTUNE.REPORT_SQL_MONITOR( sql_id=>'&p_sqlid',event_detail=>'YES',report_level=>'ALL',type=>'TEXT') from dual;
11-May
DBA_HIST_ACTIVE_SESSION_HISTORY – aggregate with SQL_PLAN_LINE_ID or SQL_PLAN_OPERATION to see in which line operation the time is spent.
Combine V$SQL_PLAN and DBA_HIST_ACTIVE_SESSION_HISTORY with SQL_ID and SQL_CHILD_NUMBER.
08-May
You can purge / enable /disable storage indexes
alter cell events = “immediate cellsrv.cellsrv_storidx(‘disable’, ‘ALL’, 0, 0, 0)”; alter cell events = “immediate cellsrv.cellsrv_storidx(‘enable’, ‘ALL’, 0, 0, 0)”; alter cell events = “immediate cellsrv.cellsrv_storidx(‘purge’, ‘ALL’, 0, 0, 0)”;
Enable / disable Flashcache compression
alter cell flashCacheCompress=TRUE.
On an X3 Exadata you should also run
alter cell flashCacheCompX3Support= TRUE
04- May
Database server disk controller configuration details – linux (run as root)
/opt/MegaRAID/MegaCli/MegaCli64 AdpAllInfo -aALL | grep “Device Present” -A 8
To check RDS protocol is sued for cluster interconnect over IB –
$ORACLE_HOME/bin/skgxpinfo
Exadata flahcache ‘write-back’ configuration is helpful to avoid ‘Free buffer waits” as the dirty blocks will be flushed to the flashcache 10x times faster than disks. Interestingly flashcache contents are persistent over cell server re-starts.
Ora600 error layers
http://www.eygle.com/digest/2010/08/ora_00600_code_explain.html
03-May
Oracle database background processes communicate with storage cells using iDB protocol which is built into the Oracle database core. iDB protocol intelligent enough to manage cell offload processing and I/O Resource Manager (IORM). iDB is built using Reliable Datagram Sockets (RDS) which is the same protocol using for RAC inter instance communication over Infiniband network. RDS is capable to do Remote Direct Memory Accesses (RDMA) to enable faster data copy by passing OS, known Zero-copy Datagram Protocol (ZDP).
Storage Server software components
Cell Server (CellSRV) : Is the core of the cell server which responsible for servicing iDB requests from the DB nodes. Also manages DBRM and IORM and priorities the requests.
Management Server (MS): is the primary interface for the administrator to monitor, manage, query and administer the Exadata cells using cellcli utility. Dceli can be used to execute a single command across cell servers in the cluster.
Restart Server (RS): Ensures the ongoing functionality of the CELLSRV and MS and the storage cell is available to the database.
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