2736979 - Database Extractors occasionally failed with "Unable to instantiate class" error

Database Extractors of one managed system occasionally failed with error message as below:

"Unable to instantiate class 'Class name'! Reason: con=<Return code>"

Here are samples from HANA DB, DB6 DB.

"Unable to instantiate class 'CL_HDB_DBH_HOST_SAVEPOINTS'! Reason: con=7"
"Unable to instantiate class 'CL_DB6_DBH_TABLESPACES'! Reason: con=1"

"Database error 12154 at CON" error with SM_EFWK user occurred at the same time in the system log of Solution Manager like below.

DD.MM.YYYY HH:MM:SS <server>_<SID>_<instance No.> DIA <wp No.> <Client No.> SM_EFWK  BY2 Database error 12154 at CON
DD.MM.YYYY HH:MM:SS <server>_<SID>_<instance No.> DIA <wp No.> <Client No.> SM_EFWK  BY0 > con=<RC>

From the corresponding dev_w* trace, similar error is detected.

"C ORA-12154: TNS:could not resolve the connect identifier specified
C *** ERROR => CONNECT failed with SQL error '12154' "

Database error 12154 is a general Oracle DB error.
ORA-12154 occurs while database extractors executed though the database type of the corresponding managed system is not Oracle.

KBA , SV-SMG-DIA-SRV-EFW , Extractor Framework , BC-DB-DBI , DB Independent Database Interface , Problem