Call now: 252-767-6166  
Oracle Training Oracle Support Development Oracle Apps

 E-mail Us
 Oracle Articles
New Oracle Articles

 Oracle Training
 Oracle Tips

 Oracle Forum
 Class Catalog

 Remote DBA
 Oracle Tuning
 Emergency 911
 RAC Support
 Apps Support
 Oracle Support

 SQL Tuning

 Oracle UNIX
 Oracle Linux
 Remote s
 Remote plans
 Application Server

 Oracle Forms
 Oracle Portal
 App Upgrades
 SQL Server
 Oracle Concepts
 Software Support

 Remote S


 Consulting Staff
 Consulting Prices
 Help Wanted!


 Oracle Posters
 Oracle Books

 Oracle Scripts

Don Burleson Blog 







ORA-1115 IO error reading block from file tips

Oracle Database Tips by Donald BurlesonFebruary 11, 2015

Question:  I am running a dbms_stats job with default_degree and I'm getting a ORA-01115 error.  This is an 8 CPU server running 10g on HP/UX.

    GRANULARITY      => 'ALL',
    CASCADE          => TRUE,
    OPTIONS          => 'GATHER',

ERROR at line 1:
ORA-12801: error signaled in parallel query server P012
ORA-01115: IO error reading block from file 22 (block # 969)
ORA-27072: File I/O error

I only have 8 CPU's and I don't understand why Oracle fired-off 12 parallel query slaves (parallel query server P012).  What causes this ORA-01115 error in automatic parallel query?  When I manually reduce the parallelism, it runs fine!

Answer:  The docs note this about the ORA-01115 error, the ORA-01115 is a transient I/O error not related to block corruption:

ORA-01115: IO error reading block from file string (block # string)

Cause: Device on which the file resides is probably offline

Action: Restore access to the device

Using 12 parallel query slaves probably not optimal for an 8 CPU server, and Oracle may have over-estimated the optimal degree of parallelism.  Here are the rules I use for optimizing the degree of parallelism.

Also note that using parallel automatic tuning can HURT your performance, and I prefer to set parallelism manually, on a case-by-case basis.

I suspect that your error is caused by firing off too many parallel query slaves, but you should also check for a bug on MOSC.

You can pinpoint the tablespace and segment for an ORA-01444 error by plugging-in the file_id and block_id into this query on dba_extents:


file_id = 1030

block_id = 602122;

In some cases, the ORA-01114 error occurs when a whole disk or mount point is full. ORA-01115 can occur when you attempt to write to a file and the device with the file is either:

  1. offline OR
  2. has run out of space, possibly because it is a temporary file which was not allocated at creation time.

To resolve ORA-01114, you should either:

  1. restore access to the device OR
  2. take out files which are not needed in order to gain more space



Oracle Training at Sea
oracle dba poster

Follow us on Twitter 
Oracle performance tuning software 
Oracle Linux poster


Burleson is the American Team

Note: This Oracle documentation was created as a support and Oracle training reference for use by our DBA performance tuning consulting professionals.  Feel free to ask questions on our Oracle forum.

Verify experience! Anyone considering using the services of an Oracle support expert should independently investigate their credentials and experience, and not rely on advertisements and self-proclaimed expertise. All legitimate Oracle experts publish their Oracle qualifications.

Errata?  Oracle technology is changing and we strive to update our BC Oracle support information.  If you find an error or have a suggestion for improving our content, we would appreciate your feedback.  Just  e-mail:  

and include the URL for the page.


Burleson Consulting

The Oracle of Database Support

Oracle Performance Tuning

Remote DBA Services


Copyright © 1996 -  2017

All rights reserved by Burleson

Oracle ® is the registered trademark of Oracle Corporation.

Remote Emergency Support provided by Conversational