Row compression with range partitioned table

[Damir]

Greetings!
I have a table which is range-partitioned by a date column (one year per
table-partition).
Currently there are five table partitions (second number is the number of
rows per table-partition):
TAB_2006 338333
TAB_2007 127239
TAB_2008 174718
TAB_2009 1
TAB_2010 0
so, they all contain records except the last partition which is currently
empty (and will be empty for some time...).

The table itself was created with the option "COMPRESS YES", along with all
partitions, and then the data was loaded into the table.
No table-partitions were added (attached) afterwards.

When I try the command:
db2 reorg table [partitioned-table] resetdictionary;
I get the warning message:
SQL2220W The compression dictionary was not built for one or more data
objects.
The db2.nfy shows the following:
ADM5591W A compression dictionary could not be built for object "6" in
tablespace "5" because no eligible data was found. If a dictionary existed
a-priori it will be used instead.

The statistics for the table show that there is no compression at all in the
table:

AVGROWSIZE AVGCOMPRESSEDROWSIZE PCTPAGESSAVED AVGROWCOMPRESSIONRATIO
PCTROWSCOMPRESSED
---------- -------------------- ------------- ------------------------ ------------------------
612 0 0 +0,00000E+000
+0,00000E+000

What could be the problem here, why does the row compression not work?
Because of the empty table partition?
Because I don't read the table stats the right way?

Any ideas?

Regards,
Damir

[Serge Rielau]

Damir,

I don't think you have an issue here.
What you got was a warning, not an error. It looks like you got
compressions for 2006-2008.
Note that in DB2 9.5 the remaining partitions will automatically be
compressed once sufficient data becomes available.

Cheers
Serge
--
Serge Rielau
DB2 Solutions Development
IBM Toronto Lab

[Damir]

Serge,
thank you for the quick answer - the compression really did take place after
the reorg, I just failed to run the runstats :-)
So, after refreshing the stats the compression values indeed look very good
for the table:

AVGROWSIZE AVGCOMPRESSEDROWSIZE PCTPAGESSAVED AVGROWCOMPRESSIONRATIO
PCTROWSCOMPRESSED
---------- -------------------- ------------- ------------------------ ------------------------

173 173 71 +3,53826E+000
+1,00000E+002

Regards,
Damir

"Serge Rielau" <sri...@ca.ibm.com> wrote in message
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