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Tuesday, May 6, 2008

APPL_TOP snapshot feature

When a DBA goes to adadmin and does an Update current snapshot, what happens actually ? APPL_TOP snapshot feature was a new feature introduced in AD.G. I am pasting some good information from AD.G readme where they have explained this feature:

This feature allows you to record the current set of files and file versions in your APPL_TOP using the "Maintain snapshot information" menu entry in the AD Administration "Maintain Applications Files" menu.

There are two types of APPL_TOP snapshots: current view snapshots and named snapshots. Current view snapshots are created once and updated when appropriate to maintain a consistent view of the APPL_TOP contents. Named snapshots are created once using AD Administration and not updated. Both store information about files, file versions, and bug fixes present in an APPL_TOP.

You can create as many named snapshots of each APPL_TOP as you want. You can also just create or update the current view snapshot. When creating a named snapshot for an APPL_TOP, the snapshot feature will first create or update the current view snapshot for that APPL_TOP. The bug fix information for a named snapshot is copied from the current view snapshot for that APPL_TOP.

You must run AD Administration "Maintain snapshot information" once for each APPL_TOP before you can apply any patch that contains a "compatible feature prereq" line on that APPL_TOP. Running AD Administration "Maintain snapshot information" for an APPL_TOP completely populates the APPL_TOP's current view snapshot. This complete information is required for the automatic prerequisite patch checking feature to give correct results.

AutoPatch automatically updates the list of file versions and bug fixes in the current view snapshot for each APPL_TOP as patches are applied to that APPL_TOP. The combination of running AD Administration "Maintain snapshot information" once for an APPL_TOP and AutoPatch's incremental updates ensures that the current view snapshot for a given APPL_TOP contains an accurate picture of the current set of files and bug fixes present in that APPL_TOP.

APPL_TOP snapshot information is stored in the AD_SNAPSHOTS, AD_SNAPSHOT_FILES, and AD_SNAPSHOT_BUGFIXES tables. There is currently no user interface available for viewing snapshot information. The ability to view and compare APPL_TOP snapshots is being considered for future versions of AD and Oracle Applications Manager 11i.

Some other tables which are referenced are:

SQL> select table_name
2 from dba_tab_columns
3 where column_name='FILE_VERSION_ID';

TABLE_NAME
------------------------------
AD_FILE_VERSIONS
AD_CHECK_FILES
AD_PTCH_HST_EXE_COP_TMP
AD_CHECK_FILE_TEMP
AD_SNAPSHOT_FILES
AD_PATCH_HIST_SNAPS_TEMP
AD_PROCESSED_FILES_TEMP
AD_SNAPSHOT_FILES_TEMP

and AD_FILES table.

To get the version of a file in snapshot tables, you can create a query which has a join between AD_SNAPSHOT_FILES, AD_FILES, AD_FILE_VERSIONS.

etrm.oracle.com gives some more information about the AD_SNAPSHOT_FILES table:

APPLSYS.AD_SNAPSHOT_FILES does not reference any database object

APPLSYS.AD_SNAPSHOT_FILES is referenced by following objects:

AD_FILE_SYS_SNAPSHOTS_PKG
AD_FILE_UTIL
AD_PATCH
FND_IMP_SFILEINFO_VL

Anand asked me an interesting question today (August, 31, 2010) after reading this post. How to run update current view snapshot outside of adadmin. A search on My Oracle Support revealed the package

AD_FILE_SYS_SNAPSHOTS_PKG.update_current_view

which seems to be called by adadmin.

12 comments:

Tushar Thakker said...

Great topic. Exactly what I was looking for.

althaf said...

Thx, Very good explanation.

Jignesh Kamdar said...

Vikram, great explanation as always. You friend.. Jignesh Kamdar

Vikram Das said...

Hi Jignesh,

Thanks for the encouragement. Good to hear from you.

- Vikram

Mehmood Ur Rehman said...

nice topic buddy, keep up the good work.

cheers
Mehmood
url: http://mehmoodm.blogspot.com

Battula Moshe Choudary said...

It's very nice post it helps me alot.
Thank you

Anonymous said...

Guru
Well done nice i am really happy
you are always explaining in deepth.
Awesome

Shakeel.appsdba@gmail.com
Shakeel

imgenius_348 said...

How to delete snapshot information and re-update the snapshot information to the database.

RAZA NAQVI said...

Hi

can you explain the option for list snapshots detail

shankar said...

Thanks a lot for the details. We had an issue where the file versions where correct in file system but not in snapshot tables.

And this not was helpful in fixing it!

Thanks,
Shankar

bhavani said...

How frequenlty is recommended to run snapshot using adadmin to update APPL_TOP
What are the main advantages of it and what happens if we donot run since long time
How do I know snapshots are last captured when or ran last time
every time i apply patch it says updating snapshot " is it just updating only for the files which are part of that patch"

Ramya S said...

what is list snapshots and list of snapshots

are they be deleted ? do we claim any space by delelting any space if we delete any snapshots