INFORMIX SERVER / 5725A3900 / C10 - IDS 12.10

The initial 'Blocked:ARCHIVE' phase of a backup can extend
siginifcantly depending on the size of the TBLSpace TBLSpace
partitions in the spaces to be backed up, which in turn usually
is correlated with the number of tables/fragments/indices in the
system.  In that phase the backup determines the exact set of
pages (used extents) that need to go to this particular backup.

This situation seems to be heavily aggravated by the fact that
all the disk i/o potentially related with this task is done
direclty, without taking advantage of read-ahead.

Informix versions 12.10.xC14 and onwards prevent this extra disk
i/o waiting by implementing read-ahead.

****************************************************************
* USERS AFFECTED:                                              *
* Users of Informix Server prior to 12.10.xC14 and 14.10.xC4.  *
****************************************************************
* PROBLEM DESCRIPTION:                                         *
* See Error Description                                        *
****************************************************************
* RECOMMENDATION:                                              *
* Update to Informix Server 12.10.xC14 or 14.10.xC4.           *
****************************************************************

Pre-populate the bufferpool with required pages shortly before
starting the backup, by running following stored procedure:

create procedure tblspace_tblspace2bufferpool()
define i,c int;
define max_spaceno int;
let max_spaceno = (select max(dbsnum) from sysdbspaces);

 for i in (1 to max_spaceno)
  select count(*) into c
    from syspaghdr pgh, sysptnhdr pth
   where pth.partnum = pgh.pg_partnum
     and pth.partnum = i*1024*1024+1
     and pg_pagenum  < npused;
 end for;
end procedure;

****************************************************************
* USERS AFFECTED:                                              *
* Users of Informix Server prior to 12.10.xC14 and 14.10.xC4.  *
****************************************************************
* PROBLEM DESCRIPTION:                                         *
* See Error Description                                        *
****************************************************************
* RECOMMENDATION:                                              *
* Update to Informix Server 12.10.xC14 or 14.10.xC4.           *
****************************************************************

Fixed in Informix Server 12.10.xC14 and 14.10.xC4.

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

20.04.2020
08.06.2020
08.06.2020