INFORMIX SERVER / 5725A3900 / C10 - IDS 12.10

This problem was reported running 12.10.FC7 on AIX.

I was able to create a test case that reproduces the problem on
12.10.FC14 AIX as well, but I suspect this
is not a port specific defect.

This problem seems to be triggered by concurrent inserts into a
primary replicate that includes smart
blobs.  On the target replicate, the smart blobs are often being
stored in fragmented smart blob extents
that tend to use up more space than the single extent on the
primary.

So, for instance, the reporting customerâ ™s system used  a
large smart blob space for only inserts of  two sblob
columns on a single table to hold around 3 million images.
Calculations based on ⠜oncheck -pe⠝ output of
that space showed that the target replicate was using almost
27GB more space for these smart blobs than
on the primary.

It was observed that there is a slight amount of extent
fragmentation for sblobs on the primary but a
considerable amount more on the target.  With no concurrency,
since this space only receives smart blob
inserts (no updates, or deletes) there is no fragmentation of
these extents, so itâ ™s a bit confusing why
there is any fragmentation of extents at all, especially on the
target where itâ ™s abundant.

My test case shows both the fragmentation of extents and the
larger space usage on the target.

****************************************************************
* USERS AFFECTED:                                              *
* Users of Informix Server prior to 12.10.xC15 and 14.10.xC6.  *
****************************************************************
* PROBLEM DESCRIPTION:                                         *
* See Error Description                                        *
****************************************************************
* RECOMMENDATION:                                              *
* Upgrade to Informix Server 12.10.xC15 (when available) or    *
* 14.10.xC6 (when available).                                  *
****************************************************************

****************************************************************
* USERS AFFECTED:                                              *
* Users of Informix Server prior to 12.10.xC15 and 14.10.xC6.  *
****************************************************************
* PROBLEM DESCRIPTION:                                         *
* See Error Description                                        *
****************************************************************
* RECOMMENDATION:                                              *
* Upgrade to Informix Server 12.10.xC15 (when available) or    *
* 14.10.xC6 (when available).                                  *
****************************************************************

Fixed in Informix Server 12.10.xC15 and 14.10.xC6.

Date  - problem reported    :
Date  - problem closed      :
Date  - last modified       :

03.09.2020
12.05.2021
12.05.2021