INFORMIX SERVER / 5725A3900 / C10 - IDS 12.10

While a backup is progressing, any pages being modified that
have not yet gone to the backup will have their before images
collected in special per-dbspace temp partitions. Should such
temp partition be unable to grow because of its containing
dbspace running out of space, a new partition would be allocated
(in a different dbspace) to accommodate more before images.
Unfortunately a similar thing does not happen if such partition
has reached its maximum size (with its home space still offering
space), and instead before images will be accumulated on an
in-memory queue, either for the one dbspace the full before
image partition is associated with or, in case of whole system
backup, for all dbspaces.

As a consequence a large amount of memory might get allocated
throughout the remainder of the backup.

Signs for hitting this problem:

a) a line like this in onstat -g arc:

num   DBSpace            Q Size Q Len  Buffer partnum    size
scanner
8     dbspace1            2251000 2250931 16     0x2300238
16777200

with 'size' columns showing a value at or very close to
16*1024*1024.
The 'Q Size' value would be an indication of how many more
before images got queue in memory.

b) an 'archbackup2' thread, in onstat -g ath, showing state
'terminated' like this:

 123772 arcbackup2       11cpu    09/20 02:53:29       66.9910
3439120    terminated

****************************************************************
* USERS AFFECTED:                                              *
* Users of Informix Server prior to 12.10.xC16 and 14.10.xC10. *
****************************************************************
* PROBLEM DESCRIPTION:                                         *
* See Error Description                                        *
****************************************************************
* RECOMMENDATION:                                              *
* Upgrade to Informix Server 12.10.xC16 or 14.10.xC10.         *
****************************************************************

****************************************************************
* USERS AFFECTED:                                              *
* Users of Informix Server prior to 12.10.xC16 and 14.10.xC10. *
****************************************************************
* PROBLEM DESCRIPTION:                                         *
* See Error Description                                        *
****************************************************************
* RECOMMENDATION:                                              *
* Upgrade to Informix Server 12.10.xC16 or 14.10.xC10.         *
****************************************************************

Fixed in Informix Server 12.10.xC16 and 14.10.xC10.

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

26.09.2022
15.05.2023
15.05.2023