Informix inserts get slower

Hello, We are running 11.50.FC8 on SunOS 5.10. We have a application which writes to 2 instances of Informix, one instance is a simple standalone server while the other instance is on HDR and has a Secondary and RSS attached to it. The problem is with one table (lets call it tqh) where contains a weeks data at the max (it's current size is 12.5 GB with 3 days of data, so approx 4 GB per day) and this data is copied to a history table on a weekend and then deleted from the above servers. The process works fine for 3-4 weeks and suddenly we see very slow inserts on the server which is a part of HDR. It suddenly starts taking 3-4 hours more to load days record if compared with other standalone server. The workaround is to rebuild the table (and indexes) and everything is back to normal. Please note, the table is unfragmented table and below is my onconfig IBM Informix Dynamic Server Version 11.50.FC8 -- On-Line (Prim) -- Up 36 days 05:46:53 -- 12588032 Kbytes Configuration File: /opt/informix/etc/onconfig #################################################################### Licensed Material - Property Of IBM # # "Restricted Materials of IBM" # # IBM Informix Dynamic Server # Copyright IBM Corporation 1996, 2010. All rights reserved. # # Title: onconfig.std # Description: IBM Informix Dynamic Server Configuration Parameters # # Important: $INFORMIXDIR now resolves to the environment # variable INFORMIXDIR. Replace the value of the INFORMIXDIR # environment variable only if the path you want is not under # $INFORMIXDIR. # # For additional information on the parameters: # http://publib.boulder.ibm.com/infocenter/idshelp/v115/index.jsp ################################################################### ################################################################### # Root Dbspace Configuration Parameters ################################################################### # ROOTNAME - The root dbspace name to contain reserved pages and # internal tracking tables. # ROOTPATH - The path for the device containing the root dbspace # ROOTOFFSET - The offset, in KB, of the root dbspace into the # device. The offset is required for some raw devices. # ROOTSIZE - The size of the root dbspace, in KB. The value of # 200000 allows for a default user space of about # 100 MB and the default system space requirements. # MIRROR - Enable (1) or disable (0) mirroring # MIRRORPATH - The path for the device containing the mirrored # root dbspace # MIRROROFFSET - The offset, in KB, into the mirrored device # # Warning: Always verify ROOTPATH before performing # disk initialization (oninit -i or -iy) to # avoid disk corruption of another instance ################################################################### ROOTNAME rootdbs ROOTPATH /home/informix/chunks/chunk1001 ROOTOFFSET 0 ROOTSIZE 4000000MIRROR 0 MIRRORPATH MIRROROFFSET 0 ################################################################### # Physical Log Configuration Parameters ################################################################### # PHYSFILE - The size, in KB, of the physical log on disk. # If RTO_SERVER_RESTART is enabled, the # suggested formula for the size of PHSYFILE # (up to about 1 GB) is: # PHYSFILE = Size of BUFFERS * 1.1 # PLOG_OVERFLOW_PATH - The directory for extra physical log files # if the physical log overflows during recovery # or long transaction rollback # PHYSBUFF - The size of the physical log buffer, in KB ################################################################### PHYSFILE 9900000 PLOG_OVERFLOW_PATH /opt/informix/tmp PHYSBUFF 512 ################################################################### # Logical Log Configuration Parameters ################################################################### # LOGFILES - The number of logical log files # LOGSIZE - The size of each logical log, in KB # DYNAMIC_LOGS - The type of dynamic log allocation. # Acceptable values are: # 2 Automatic. IDS adds a new logical log to the # root dbspace when necessary. # 1 Manual. IDS notifies the DBA to add new logical # logs when necessary. # 0 Disabled # LOGBUFF - The size of the logical log buffer, in KB ################################################################### LOGFILES 90 LOGSIZE 1000 DYNAMIC_LOGS 2 LOGBUFF 256 ################################################################### # Long Transaction Configuration Parameters ################################################################### # If IDS cannot roll back a long transaction, the server hangs # until more disk space is available. # # LTXHWM - The percentage of the logical logs that can be # filled before a transaction is determined to be a # long transaction and is rolled back # LTXEHWM - The percentage of the logical logs that have been # filled before the server suspends all other # transactions so that the long transaction being # rolled back has exclusive use of the logs # # When dynamic logging is on, you can set higher values for # LTXHWM and LTXEHWM because the server can add new logical logs # during long transaction rollback. Set lower values to limit the # number of new logical logs added. # # If dynamic logging is off, set LTXHWM and LTXEHWM to # lower values, such as 50 and 60 or lower, to prevent long # transaction rollback from hanging the server due to lack of # logical log space. # # When using Enterprise Replication, set LTXEHWM to at least 30% # higher than LTXHWM to minimize log overruns. ################################################################### LTXHWM 50 LTXEHWM 60 ################################################################### # Server Message File Configuration Parameters ################################################################### # MSGPATH - The path of the IDS message log file # CONSOLE - The path of the IDS console message file ################################################################### MSGPATH /opt/informix/online.log CONSOLE /opt/informix/online.con ################################################################### # Tblspace Configuration Parameters ################################################################### # TBLTBLFIRST - The first extent size, in KB, for the tblspace # tblspace. Must be in multiples of the page size. # TBLTBLNEXT - The next extent size, in KB, for the tblspace # tblspace. Must be in multiples of the page size. # The default setting for both is 0, which allows IDS to manage # extent sizes automatically. # # TBLSPACE_STATS - Enables (1) or disables (0) IDS to maintain # tblspace statistics ################################################################### TBLTBLFIRST 0 TBLTBLNEXT 0 TBLSPACE_STATS 1 ################################################################### # Temporary dbspace and sbspace Configuration Parameters ################################################################### # DBSPACETEMP - The list of dbspaces used to store temporary # tables and other objects. Specify a colon # separated list of dbspaces that exist when the # server is started. If no dbsp