INFORMIX SERVER / 5725A3900 / C10 - IDS 12.10

If using compression on a table with varchars, and then doing an 
in place alter of the table, it's possible if readers are 
querying the table using committed read last committed while the 
table is being updated that the above assertion failures are 
possible for the sessions reading the table. 
 
The stack for the 2 assertions (for the rowalter): 
 
affail_interface 
rowalter 
rsseqscan_read 
fmseqscan_read 
readseq_batch 
gettupl 
scan_next 
next_row 
get_first_row_from_producer 
group_open 
prepselect 
open_cursor 
sql_open 
sq_open 
sqmain 
 
For the decompress row: 
 
affail_interface 
rsseqscan_read 
fmseqscan_read 
readseq_batch 
gettupl 
scan_next 
next_row 
get_first_row_from_producer 
group_open 
prepselect 
open_cursor 
sql_open 
sq_open 
sqmain 
 
Again for this to occur, the table being queried needs to be 
using compression, contain varchars, and have some in place 
alter being performed on it which would alter the rows size. 
Then the users querying the table need to be using committed 
read last committed isolation level. 
 
If the table is not using compression you can see the 2 
following types of assertion failures instead: 
 
13:23:07  Assert Failed: physical_scan: corrupted rowid = 1ce01, 
partnum = 100102 
 
or 
 
08:00:52  Assert Failed: construct_row: deleted rowid = 41c, 
partnum = 100102

**************************************************************** 
* USERS AFFECTED:                                              * 
* users using last committed in 12.10                          * 
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* PROBLEM DESCRIPTION:                                         * 
* See Error Description                                        * 
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* RECOMMENDATION:                                              * 
* Update to IDS-12.10.xC5                                      * 
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Problem Fixed In IDS-12.10.xC5

not known / see Local fix

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

31.07.2014
16.10.2015
16.10.2015