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Incremental autorefresh becomes full autorefresh
Specify the tablespace when you create the cache administration user on Oracle. You
can also specify the tablespace after user creation with the DEFAULT TABLESPACE
clause of the Oracle ALTER USER statement.
Change log tables for each of the cached Oracle tables reside in the cache
administration user tablespace. For each update on an Oracle table, one row (a change
log record) is inserted into the change log table for that Oracle table. The size of a
change log record in bytes is as follows:
size of change log record = size of primary key on Oracle table + 250
The number of records in a change log table depends on the update rate on the Oracle
table and on the autorefresh interval on TimesTen. Every 20 seconds, TimesTen
removes change log records that have been applied to all databases that cache the
associated Oracle table.
When change logs are removed, a message similar to the following is displayed in the
support log:
16:32:26.73 Info: ORA: 5652: ora-5652-4756-ogTblGC01036: Garbage collector
deleted 1 rows from TT_03_383270_L where logseq < 1
There are options on how to manage what happens when the cache administration
user tablespace is filled. See "Considerations when the cache administration user's
tablespace is full" on page 3-21 for more information.
Diagnosing a full cache administration user tablespace
Check for the following conditions if the cache administration user tablespace is full:
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Is the autorefresh state set to PAUSED? Change log records accumulate when the
state is PAUSED.
Has the cache group been created but not loaded? The default autorefresh state for
cache group creation is PAUSED.
Is a cache group being created or is a database being duplicated? Both of these
operations temporarily stop clean-up operations on the change log table.
Are the cache agents on all TimesTen databases running? If a cache agent is not
running, change log records accumulate.
Has a database been abandoned without dropping autorefresh cache groups in the
database? Abandoned databases result from scenarios such as the following:
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The database is destroyed by ttDestroy -force.
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The application connected to the database with the Overwrite connection
attribute set to 1, but the cache groups that were in the old database are not
re-created.
If the database still exists, connect to the abandoned database and drop the cache
group.
Use the cacheInfo.sql script to find out how large the change log tables are for
each cached Oracle table. Use the output to verify that the databases are still in use.
See "Displaying information from the change log tables" on page 3-13.
If the databases are still in use, verify that the cache agents are running.
Compare the autorefresh progress on TimesTen to the maximum log sequence number
on the change log table. If TimesTen is behind, then call the
ttCacheAutorefreshStatsGet procedure to see whether the autorefresh
3-20 Oracle TimesTen In-Memory Database Troubleshooting Procedures Guide