My Postgres RDS Database is got restarted. It says heavy consumption of memory.

My Postgres RDS Database is got restarted.
It says heavy consumption of memory.
But around 20GB freeable memory available at the time of restart. As I checked AAS Graph there is more locking happening. Below are the logs.

PL/pgSQL function evaluate_program_payout_version(character varying,character varying,character varying,character varying,character varying,character varying,character varying,character varying,character varying,character varying,character varying,character varying,character varying,character varying,character varying,character varying) line 141 at SQL statement
2022-03-08 11:28:42 UTC:10.10.3.18(33366):pmli_bre_uat@dmsclientdb:[10065]:WARNING: terminating connection because of crash of another server process
2022-03-08 11:28:42 UTC:10.10.3.18(33366):pmli_bre_uat@dmsclientdb:[10065]:DETAIL: The postmaster has commanded this server process to roll back the current transaction and exit, because another server process exited abnormally and possibly corrupted shared memory.
2022-03-08 11:28:42 UTC:10.10.3.18(33366):pmli_bre_uat@dmsclientdb:[10065]:HINT: In a moment you should be able to reconnect to the database and repeat your command.
2022-03-08 11:28:42 UTC:10.10.3.18(33366):pmli_bre_uat@dmsclientdb:[10065]:CONTEXT: SQL statement "delete FROM EvalSlabResult
WHERE contextid = par_context_id
and program_code = par_program_code
and start_date = var_start_date"
PL/pgSQL function evaluate_slab_version(character varying,character varying,character varying,character varying,character varying,character varying,character varying,character varying,character varying,character varying,character varying,character varying,character varying,character varying) line 139 at SQL statement
2022-03-08 11:28:42 UTC:10.10.3.18(33300):pmli_bre_uat@dmsclientdb:[9065]:WARNING: terminating connection because of crash of another server process
2022-03-08 11:28:42 UTC:10.10.3.18(33300):pmli_bre_uat@dmsclientdb:[9065]:DETAIL: The postmaster has commanded this server process to roll back the current transaction and exit, because another server process exited abnormally and possibly corrupted shared memory.
2022-03-08 11:28:42 UTC:10.10.3.18(33300):pmli_bre_uat@dmsclientdb:[9065]:HINT: In a moment you should be able to reconnect to the database and repeat your command.
2022-03-08 11:28:42 UTC:10.10.3.18(33286):pmli_bre_uat@dmsclientdb:[8793]:WARNING: terminating connection because of crash of another server process
2022-03-08 11:28:42 UTC:10.10.3.18(33286):pmli_bre_uat@dmsclientdb:[8793]:DETAIL: The postmaster has commanded this server process to roll back the current transaction and exit, because another server process exited abnormally and possibly corrupted shared memory.
2022-03-08 11:28:42 UTC:10.10.3.18(33286):pmli_bre_uat@dmsclientdb:[8793]:HINT: In a moment you should be able to reconnect to the database and repeat your command.
2022-03-08 11:28:42 UTC::@:[13295]:FATAL: Can't handle storage runtime process crash
2022-03-08 11:28:42 UTC::@:[13295]:LOG: database system is shut down
2022-03-08 11:28:42 UTC:10.10.3.18(33448):pmli_bre_uat@dmsclientdb:[11092]:WARNING: terminating connection because of crash of another server process
2022-03-08 11:28:42 UTC:10.10.3.18(33448):pmli_bre_uat@dmsclientdb:[11092]:DETAIL: The postmaster has commanded this server process to roll back the current transaction and exit, because another server process exited abnormally and possibly corrupted shared memory.
2022-03-08 11:28:42 UTC:10.10.3.18(33448):pmli_bre_uat@dmsclientdb:[11092]:HINT: In a moment you should be able to reconnect to the database and repeat your command.
2022-03-08 11:28:42 UTC:10.10.3.18(33448):pmli_bre_uat@dmsclientdb:[11092]:CONTEXT: SQL statement "delete FROM DVResult
WHERE contextid = par_context_id
and program_code = par_program_code
and start_date = var_start_date"
PL/pgSQL function evaluate_dv_version(character varying,character varying,character varying,character varying,character varying,character varying,character varying,character varying,character varying,character varying,character varying,character varying,character varying,character varying,character varying,character varying) line 143 at SQL statement
2022-03-08 11:28:42 UTC:10.10.3.18(33378):pmli_bre_uat@dmsclientdb:[10069]:WARNING: terminating connection because of crash of another server process
2022-03-08 11:28:42 UTC:10.10.3.18(33378):pmli_bre_uat@dmsclientdb:[10069]:DETAIL: The postmaster has commanded this server process to roll back the current transaction and exit, because another server process exited abnormally and possibly corrupted shared memory.
2022-03-08 11:28:42 UTC:10.10.3.18(33378):pmli_bre_uat@dmsclientdb:[10069]:HINT: In a moment you should be able to reconnect to the database and repeat your command.
2022-03-08 11:28:42 UTC:10.10.3.18(33378):pmli_bre_uat@dmsclientdb:[10069]:CONTEXT: SQL statement "SELECT ess.entityid, ess.version_id FROM evalslabsummary ess
WHERE ess.contextid = par_contextid
AND ess.program_code = par_program_code
AND ess.start_date = var_start_date"
PL/pgSQL function evaluate_slab(character varying,character varying,character varying,character varying,character varying) line 71 at SQL statement
2022-03-08 11:28:42 UTC:10.10.3.18(33408):pmli_bre_uat@dmsclientdb:[10455]:WARNING: terminating connection because of crash of another server process
2022-03-08 11:28:42 UTC:10.10.3.18(33408):pmli_bre_uat@dmsclientdb:[10455]:DETAIL: The postmaster has commanded this server process to roll back the current transaction and exit, because another server process exited abnormally and possibly corrupted shared memory.
2022-03-08 11:28:42 UTC:10.10.3.18(33408):pmli_bre_uat@dmsclientdb:[10455]:HINT: In a moment you should be able to reconnect to the database and repeat your command.
2022-03-08 11:28:42 UTC:10.10.3.18(33408):pmli_bre_uat@dmsclientdb:[10455]:CONTEXT: SQL statement "delete FROM DVResult
WHERE contextid = par_context_id
and program_code = par_program_code
and start_date = var_start_date"
PL/pgSQL function evaluate_dv_version(character varying,character varying,character varying,character varying,character varying,character varying,character varying,character varying,character varying,character varying,character varying,character varying,character varying,character varying,character varying,character varying) line 143 at SQL statement
2022-03-08 11:28:42 UTC:10.10.3.18(33328):pmli_bre_uat@dmsclientdb:[9247]:WARNING: terminating connection because of crash of another server process
2022-03-08 11:28:42 UTC:10.10.3.18(33328):pmli_bre_uat@dmsclientdb:[9247]:DETAIL: The postmaster has commanded this server process to roll back the current transaction and exit, because another server process exited abnormally and possibly corrupted shared memory.
2022-03-08 11:28:42 UTC:10.10.3.18(33328):pmli_bre_uat@dmsclientdb:[9247]:HINT: In a moment you should be able to reconnect to the database and repeat your command.
2022-03-08 11:28:42 UTC:10.10.3.18(33328):pmli_bre_uat@dmsclientdb:[9247]:CONTEXT: SQL statement "delete FROM ProgramPayoutResult
WHERE contextid = par_context_id
and program_code = par_program_code
and start_date = var_start_date"
PL/pgSQL function evaluate_program_payout_version(character varying,character varying,character varying,character varying,character varying,character varying,character varying,character varying,character varying,character varying,character varying,character varying,character varying,character varying,character varying,character varying) line 141 at SQL statement
2022-03-08 11:28:42 UTC:10.10.3.18(33474):pmli_bre_uat@dmsclientdb:[12157]:WARNING: terminating connection because of crash of another server process
2022-03-08 11:28:42 UTC:10.10.3.18(33474):pmli_bre_uat@dmsclientdb:[12157]:DETAIL: The postmaster has commanded this server process to roll back the current transaction and exit, because another server process exited abnormally and possibly corrupted shared memory.
2022-03-08 11:28:42 UTC:10.10.3.18(33474):pmli_bre_uat@dmsclientdb:[12157]:HINT: In a moment you should be able to reconnect to the database and repeat your command.
2022-03-08 11:28:42 UTC:10.10.3.18(33474):pmli_bre_uat@dmsclientdb:[12157]:CONTEXT: SQL statement "delete FROM ProgramPayoutResult
WHERE contextid = par_context_id
and program_code = par_program_code
and start_date = var_start_date"
PL/pgSQL function evaluate_program_payout_version(character varying,character varying,character varying,character varying,character varying,character varying,character varying,character varying,character varying,character varying,character varying,character varying,character varying,character varying,character varying,character varying) line 141 at SQL statement
2022-03-08 11:28:42 UTC:10.10.3.18(33236):pmli_bre_uat@dmsclientdb:[7485]:WARNING: terminating connection because of crash of another server process
2022-03-08 11:28:42 UTC:10.10.3.18(33236):pmli_bre_uat@dmsclientdb:[7485]:DETAIL: The postmaster has commanded this server process to roll back the current transaction and exit, because another server process exited abnormally and possibly corrupted shared memory.
2022-03-08 11:28:42 UTC:10.10.3.18(33236):pmli_bre_uat@dmsclientdb:[7485]:HINT: In a moment you should be able to reconnect to the database and repeat you