PGA 'kol vstring'

Hello,

we mitgratet from Oracle Database 11.2.0.3 SE1 to 19.3.

We are observing a constantly growing PGA consumption for all our processes that run as PL/SQL package. In average it is 10 MB more per day.

We use dedicated server connections. OS is now Linux CentOS 7.6 and was CentOS 6.1 before. The old system wir 11g R2 had no problems in terms of memory consumption.

Investigations revealed that 'kol vstring' is growing constantly. Here the biggest heap buffers of one of our process:

SELECT TO_CHAR (RATIO_TO_REPORT(bytes) OVER () * 100, '90D0') "%", category, name, heap_name, TO_CHAR (bytes, '999G999G000') "Bytes"