Panorama: Explore free space fragmentation of tablespaces

Unfortunately the number of free bytes in your tablespaces does not really ensure that you are still able to allocate new extents in tablespace.

Except you have choosen UNIFORM EXTENT SIZE as allocation type, than your free space chunks may not be smaller than your uniform extent size and you can skip here.

To allocate a new extent on one of your tablespace's objects you must ensure that there is an existing contiguous chunk of free space that your extent may totally fit in.

With Panorama you are enabled to explore with one click the fragmentation of your tablespace and remaining space for different extent sizes.





There may be a remaining question:
With what size will the next extent be created for my table or index to estimate wether it will fit in free space?

You can recognize this by exploration of the existing extents of your object and the assumption that the next extent will be created with:
  • the size of the largest existing extent for SYSTEM allocation type
  • the next extent size of your object for USER allocation type
Panorama enables you to do this like show here



Comments

Post a Comment

Popular posts from this blog

Oracle-DB: How to check for appropriate sequence caching

Image
A common pitfall while using sequences in Oracle-DB is forgetting to define sequence caching. The default for sequences is cache size = 0. That means, every sequence.nextval operation triggers a single write operation on dictionary table sys.SEQ$. Especially if frequently calling sequence.nextval uncached sequences may cause significant performance degradation. Frequently calling sequence.nextval in parallel sessions may lead to ramdom lock scenarios in library cache. Setting a cache size for a sequence may heavy increase performance of nextval-operations. There's a minimal memory overhead for caching a sequence because all that's needed is a counter to increase in SGA memory and a upper limit. If this limit is reached with the counter, the upper limit is increased by cache size and the new upper limit is written down once to SEQ$. The possible drawback for sequence caching is that you loose all your values between the current value and the highest cached value if yo
Read more

Common pitfalls using SQL*Net via Firewalls

It's very common that firewalls are terminating idle TCP sessions after a limited time, often after approximately one hour. Possible problem If you have a long running SQL or PL/SQL program and the firewall terminates your apparently idle TCP session this may lead to the following scenario: the database is not able to send result to client. After reaching the TCP-timeout the database server terminates the DB-Session the client program stays in socket read forever waiting for the database response Oracle's full solution: SQLNET.EXPIRE_TIME=x in sqlnet.ora Oracle's solution for this problem is setting parameter SQLNET.EXPIRE_TIME=x in sqlnet.ora where x are the minutes between keep alive packets on idle sessions that inform the firewall that this session is always alive. SQLNET.EXPIRE_TIME hast to be set in the sqlnet.ora of your RDBMS' ORACLE_HOME. Normally $ORACLE_HOME/network/admin. If you have a grid infrastructure setting SQLNET.EXPIRE_TIME in sqlnet
Read more

Oracle-DB: Identify excessive logon/logoff operations with short-running sessions

Image
Creating and destroying database sessions in loop may lead to significant database load. This blog post contains more about quantifying this load. Applications should use connection pooling at client or database side to prevent excessive session creation. But how can I identify the client processes causing this sessions? Scan DBA_Audit_Trail to identify context info If auditing logon/logoff-operations is activated for your database, scan DBA_Audit_Trail. You can do this by 2 was: Alternative 1: Use my tool "Panorama" to evaluate audit trail Panorama is available here. Go to menu "DBA general" / "Audit Trail": Select start and end time for selection Filter column "Action" for "LOGON" Set "Grouping" to "Minute" Execute selection via button "Show audit trail" Add columns of your choice to diagram by context menu (right mouse button) This way you can identify the machine, DB-user
Read more