Why is my Postgre server went in recovery mode all in sudden

Hi Team,

I dont have any idea why did my Postgres server crash and it says

timestamp=2018-05-07 00:34:11.209 EDT,user=,db=,app=,client=,
transaction-ID=0,session_start_timestamp=2018-04-26 10:08:19
EDT,SQL_state=00000LOG: worker process: parallel worker for PID 2864 (PID
4476) exited with exit code 0
timestamp=2018-05-07 00:34:11.209 EDT,user=,db=,app=,client=,
transaction-ID=0,session_start_timestamp=2018-04-26 10:08:19
EDT,SQL_state=00000LOG: terminating any other active server processes
timestamp=2018-05-07 00:34:11.209 EDT,user=postgres,db=Ozalo,
app=[unknown],transaction-ID=0,session_start_timestamp=2018-05-07 00:32:46
EDT,SQL_state=00000LOG: duration: 0.331 ms bind <unnamed>: SELECT
"repository"."c_token" AS "token", "repository"."c_path" AS "path"

FROM

t_e20so1_repository AS "repository" INNER JOIN t_e20so1_document_bigint
AS "documentbigint" ON "repository"."c_repositoryid" =
"documentbigint"."c_value"

WHERE "documentbigint"."c_documentid" = 201989

AND "documentbigint"."c_fieldid" = 'b035afc8-439f-4f2c-a9ae-
e054052511fd'
timestamp=2018-05-07 00:34:11.210 EDT,user=postgres,db= Ozalo,app=[unknown],
transaction-ID=0,session_start_timestamp=2018-05-07 00:32:46
EDT,SQL_state=00000LOG: duration: 0.061 ms execute <unnamed>: SELECT
"repository"."c_token" AS "token", "repository"."c_path" AS "path"
FROM
t_zs01_sys_dm AS "repository" INNER JOIN t_e20so1_document_bigint AS
"documentbigint" ON "repository"."c_repositoryid" =
"documentbigint"."c_value"
WHERE "documentbigint"."c_documentid" = 201989
AND "documentbigint"."c_fieldid" = 'b035afc8-439f-4f2c-a9ae-
e054052511fd'

after Some time i was receiving this error

timestamp=2018-05-07 00:34:11.218 EDT,user=postgres,db= Ozalo
,app=[unknown],transaction-ID=0,session_start_timestamp=2018-05-07 00:34:10
EDT,SQL_state=57P02WARNING: terminating connection because of crash of
another server process
timestamp=2018-05-07 00:34:11.218 EDT,user=postgres,db= Ozalo
,app=[unknown],transaction-ID=0,session_start_timestamp=2018-05-07 00:34:10
EDT,SQL_state=57P02DETAIL: 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.
timestamp=2018-05-07 00:34:11.218 EDT,user=postgres,db= Ozalo
,app=[unknown],transaction-ID=0,session_start_timestamp=2018-05-07 00:34:10
EDT,SQL_state=57P02HINT: In a moment you should be able to reconnect to
the database and repeat your command.

timestamp=2018-05-07 00:34:11.357 EDT,user=,db=,app=,client=,
transaction-ID=0,session_start_timestamp=2018-04-26 10:08:20
EDT,SQL_state=57P02DETAIL: 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.
timestamp=2018-05-07 00:34:11.357 EDT,user=,db=,app=,client=,
transaction-ID=0,session_start_timestamp=2018-04-26 10:08:20
EDT,SQL_state=57P02HINT: In a moment you should be able to reconnect to
the database and repeat your command.
timestamp=2018-05-07 00:34:11.379 EDT,user=postgres,db=
Ozalo,app=[unknown],,transaction-ID=0,session_start_timestamp=2018-05-07
00:34:11 EDT,SQL_state=57P03FATAL: the database system is in recovery mode
timestamp=2018-05-07 00:34:11.381 EDT,user=postgres,db=
Ozalo,app=[unknown],transaction-ID=0,session_start_timestamp=2018-05-07
00:34:11 EDT,SQL_state=57P03FATAL: the database system is in recovery mode

what is the reason it corrupted share memory ?

what is meant by 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. ?
how much of share memory if its consume it will crash

Please can any one help me in this
or else what is the reason of crash of DB server

Current using 10.3

Current Config

max_connections = 5000
shared_buffers = 7680MB
effective_cache_size = 23040MB

maintenance_work_mem = 1920MBmin_wal_size = 1GBmax_wal_size =
2GBcheckpoint_completion_target = 0.7wal_buffers =
16MBdefault_statistics_target = 100random_page_cost =
1.1effective_io_concurrency = 200max_worker_processes =
16max_parallel_workers_per_gather = 8max_parallel_workers = 16work_mem
= 196kB

Thanks