Oracle Extended Data Types
Extended Data Types is a feature as of Oracle 12c. It allows us to increase the maximum size of VARCHAR2, NVARCHAR2, and RAW columns in a table.
Prerequisites
Oracle database version 12c onward
Admin privileges to connect as SYSDBA into the database
Introduction
For versions prior to Oracle 12c, the following limits apply for the maximum size of a column:
VARCHAR2 : 4000 bytes
NVARCHAR2 : 4000 bytes
RAW : 2000 bytes
In Oracle 12c (and onward), the maximum limit is set to 32767 bytes for the following data types:
VARCHAR2 : 32767 bytes
NVARCHAR2 : 32767 bytes
RAW : 32767 bytes
Important: If you plan to execute the database update scripts for censhare 2020.1, check for specific indexes under asset_feature table. Otherwise, an update error can occur. For detailed instructions, see Before update to 2020.1.
Enable the Extended Data Types
The extended data types feature is controlled by using the MAX_STRING_SIZE initialization parameter. The default value is STANDARD, which restricts the maximum sizes to the traditional lengths. Setting the parameter value to EXTENDED, allows us to use the new maximum lengths.
The process of switching to the extended data types is a one-way operation. Once, you have switched to extended data types you cannot go back without some form of database recovery. In addition to changing the parameter, you must run the utl32k.sql script to invalidate and recompile any object that may be affected by the maximum length changes.
Execute the upgrade
As an admin, execute the following commands:
CONN / AS SYSDBA -- If you have not connected before, introduce the user and pass of an admin. -- Precaution to prevent possible failures. Suggested by Hristiyan. PURGE DBA_RECYCLEBIN SHUTDOWN IMMEDIATE; STARTUP UPGRADE; ALTER SYSTEM SET max_string_size=extended; @?/rdbms/admin/utl32k.sql SHUTDOWN IMMEDIATE; STARTUP;
Watch the Output
The utl32k.sql script produces output that looks something like this:
Session altered.
DOC>#######################################################################
DOC>#######################################################################
DOC> The following statement will cause an "ORA-01722: invalid number"
DOC> error if the database has not been opened for UPGRADE.
DOC>
DOC> Perform a "SHUTDOWN ABORT" and
DOC> restart using UPGRADE.
DOC>#######################################################################
DOC>#######################################################################
DOC>#
no rows selected
DOC>#######################################################################
DOC>#######################################################################
DOC> The following statement will cause an "ORA-01722: invalid number"
DOC> error if the database does not have compatible >= 12.0.0
DOC>
DOC> Set compatible >= 12.0.0 and retry.
DOC>#######################################################################
DOC>#######################################################################
DOC>#
PL/SQL procedure successfully completed.
Session altered.
0 rows updated.
Commit complete.
System altered.
PL/SQL procedure successfully completed.
Commit complete.
System altered.
Session altered.
PL/SQL procedure successfully completed.
No errors.
Session altered.
PL/SQL procedure successfully completed.
Commit complete.
Package altered.
TIMESTAMP
--------------------------------------------------------------------------------
COMP_TIMESTAMP UTLRP_BGN 2013-07-10 10:11:26
DOC> The following PL/SQL block invokes UTL_RECOMP to recompile invalid
DOC> objects in the database. Recompilation time is proportional to the
DOC> number of invalid objects in the database, so this command may take
DOC> a long time to execute on a database with a large number of invalid
DOC> objects.
DOC>
DOC> Use the following queries to track recompilation progress:
DOC>
DOC> 1. Query returning the number of invalid objects remaining. This
DOC> number should decrease with time.
DOC> SELECT COUNT(*) FROM obj$ WHERE status IN (4, 5, 6);
DOC>
DOC> 2. Query returning the number of objects compiled so far. This number
DOC> should increase with time.
DOC> SELECT COUNT(*) FROM UTL_RECOMP_COMPILED;
DOC>
DOC> This script automatically chooses serial or parallel recompilation
DOC> based on the number of CPUs available (parameter cpu_count) multiplied
DOC> by the number of threads per CPU (parameter parallel_threads_per_cpu).
DOC> On RAC, this number is added across all RAC nodes.
DOC>
DOC> UTL_RECOMP uses DBMS_SCHEDULER to create jobs for parallel
DOC> recompilation. Jobs are created without instance affinity so that they
DOC> can migrate across RAC nodes. Use the following queries to verify
DOC> whether UTL_RECOMP jobs are being created and run correctly:
DOC>
DOC> 1. Query showing jobs created by UTL_RECOMP
DOC> SELECT job_name FROM dba_scheduler_jobs
DOC> WHERE job_name like 'UTL_RECOMP_SLAVE_%';
DOC>
DOC> 2. Query showing UTL_RECOMP jobs that are running
DOC> SELECT job_name FROM dba_scheduler_running_jobs
DOC> WHERE job_name like 'UTL_RECOMP_SLAVE_%';
DOC>#
PL/SQL procedure successfully completed.
TIMESTAMP
--------------------------------------------------------------------------------
COMP_TIMESTAMP UTLRP_END 2013-07-10 10:11:33
DOC> The following query reports the number of objects that have compiled
DOC> with errors.
DOC>
DOC> If the number is higher than expected, please examine the error
DOC> messages reported with each object (using SHOW ERRORS) to see if they
DOC> point to system misconfiguration or resource constraints that must be
DOC> fixed before attempting to recompile these objects.
DOC>#
OBJECTS WITH ERRORS
-------------------
0
DOC> The following query reports the number of errors caught during
DOC> recompilation. If this number is non-zero, please query the error
DOC> messages in the table UTL_RECOMP_ERRORS to see if any of these errors
DOC> are due to misconfiguration or resource constraints that must be
DOC> fixed before objects can compile successfully.
DOC>#
ERRORS DURING RECOMPILATION
---------------------------
0
Function created.
PL/SQL procedure successfully completed.
Function dropped.
...Database user "SYS", database schema "APEX_040200", user# "98" 11:26:30
...Compiled 0 out of 2998 objects considered, 0 failed compilation 11:26:31
...263 packages
...255 package bodies
...453 tables
...11 functions
...16 procedures
...3 sequences
...458 triggers
...1322 indexes
...207 views
...0 libraries
...6 types
...0 type bodies
...0 operators
...0 index types
...Begin key object existence check 11:26:31
...Completed key object existence check 11:26:31
...Setting DBMS Registry 11:26:31
...Setting DBMS Registry Complete 11:26:31
...Exiting validate 11:26:31
PL/SQL procedure successfully completed.
SQL>Extend the size of database columns
After successfully executing the previous commands, you can extend the size of the columns of the mentioned types.
As mentioned above: The type of the database column must be one of these: VARCHAR2, NVARCHAR2, and RAW.
To extend the size, execute the following command:
For example:
Note: Normally, after applying the extended data type to the Oracle database, there is no need to execute any additional commands to increase the size of the desired column. The pre-update sql scripts and the new installations (censhare 2019.3 or higher) take care of that step by introducing the new default sizes.
Before update to censhare 2020.1
The 2019_3_maxversion-t-2020_1_0-01-pre.sql update script extends the size of value_string column of asset_feature table. Using this, the extended data type must have been activated.
For some installations, there can be defined indexes for the asset_feature table that can cause the update script to fail. The following change command in the update script then cannot be executed:
The following indexes have been found to block the change command:
ASSET_FEATURE_IDX4
ASSET_FEATURE_IDX5
ASSET_FEATURE_IDX6
ASSET_FEATURE_IDX7
ASSET_FEATURE_IDX9
Use the following command to check if these indexes exist for the asset_feature table:
If so, delete these indexes:
After that, the change command in the update script should not fail.