INFORMIX SERVER / 5725A3900 / E10 - 

Informix sensor mon_table_profile would have to be corrected
because it returns the wrong serial value when column type is
modified from serial to bigserial/serial8 datatype

When column type is getting modified from serial to
seril8/bigserial the code is still calculating the value based
on serial data type instead of calculating the value based on
modified column datatype serial8/bigserial.

Consider this example :

decode(cur_serial8, 1, cur_serial4::int8, cur_serial8) as value
for the column serialval of the sensor result table.

Insert 18 rows into the table

cur_serial4         cur_serial8       cur_bigserial

        18                   1                   1

then  alter the serial4 to bigserial and then:

cur_serial4         cur_serial8       cur_bigserial

        18                   1                   18

then insert 2 new rows and then:

cur_serial4         cur_serial8       cur_bigserial

        18                   1                   20

When the sensor run with the decode(cur_serial8, 1,
cur_serial4::int8, cur_serial8)

18 is inserted as serialval in the result table
mon_table_profile, but the correct value is 20.


The assumption in that decode() expressions seems to be that an
unused serial counter always is 1, so you could tell `the used
one` from its value being different from 1, yet
 - this only is true if a serial counter never was used on a
given partition
   - it wouldn`t be reset upon an ALTER TABLE modifying such
column (to e.g. a different serial type)
 - it is possible to have two serial types in use on a given
table (serial + serial8, or serial + bigserial), posing yet
another complication for this query

****************************************************************
* USERS AFFECTED:                                              *
* Users of Informix Server prior to 14.10.xC7.                 *
****************************************************************
* PROBLEM DESCRIPTION:                                         *
* See Error Description                                        *
****************************************************************
* RECOMMENDATION:                                              *
* Upgrade to Informix Server 14.10.xC7.                        *
****************************************************************

****************************************************************
* USERS AFFECTED:                                              *
* Users of Informix Server prior to 14.10.xC7.                 *
****************************************************************
* PROBLEM DESCRIPTION:                                         *
* See Error Description                                        *
****************************************************************
* RECOMMENDATION:                                              *
* Upgrade to Informix Server 14.10.xC7.                        *
****************************************************************

Fixed in Informix Server 14.10.xC7.

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

07.11.2019
02.11.2021
02.11.2021