Pages allocated / pages used
Marc Demhartner, on 14.10.FC7, found a 4K-page table with 182 columns still showing 16777215 pages used after deleting rows. David Williams said to repack and shrink. Doug Lawry gave the sysadmin task 'table repack shrink' and a faster rebuild using ALTER TABLE TYPE (RAW), ALTER FRAGMENT INIT and TYPE (STANDARD), with MAX_FILL_DATA_PAGES.
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Hi Fellas, we have a RHEL8 system with 14.10.FC7WE running. 4K dbspace with a huge wide table with 182 columns and ~10 million rows. Number of pages allocated 16777215 Number of pages used 16777215 Problem is, that we already reducded that table from ~28m to 10m now and again we see that issue with pages. Informix is not releasing the pages when we do a delete? ------------------------------ Marc Demhartner ------------------------------ #Informix
Hi Marc, You need to repack and shrink after deleting. Regards, David. ------------------------------ David Williams ------------------------------
Could you give me an example how to do so ? ------------------------------ Marc Demhartner ------------------------------
Hi Marc.
David probably means this:
EXECUTE FUNCTION sysadmin:task('table repack shrink', 'table-name
');
That could take a long time. If you can tolerate the table being locked and have room for a copy, the quickest method is:
ALTER TABLE
table-name
TYPE (RAW);
ALTER FRAGMENT ON TABLEtable-name
INIT IN
same-dbspace
;
ALTER TABLE
table-name
TYPE (STANDARD);
That may refuse if there are referential constraints, and you should ideally take a level 0 archive afterwards.
If the table contains variable length columns, consider setting this before the rebuild.
onmode -wfMAX_FILL_DATA_PAGES
=1
Regards,Doug
------------------------------
Doug Lawry
Oninit Consulting
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