too high planning time

Hello Team,

I have a problem with the explain analyze' output of some queries. There is
too high planning time, but the execution time is relatively low. What is
the possible reason behind this problem? I also ran the vacuum and analyze
commands for the table.

EXPLAIN ANALYZE select
i."DefinitionId",
from
"T_WF_INSTANCE" i
where
i."InstanceId" = 10045683193;

QUERY PLAN

--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Index Scan using
"T_WF_INSTANCE_InstanceId_ApplicationCd_EntityStatusCd_idx" on
"T_WF_INSTANCE" i (cost=0.57..2.79 rows=1 width=34) (actual
time=2.522..2.522 rows=1 loops=1)
Index Cond: ("InstanceId" = '10045683193'::bigint)

* Planning Time: 8460.446 ms Execution Time: 2.616 ms*
(4 rows)

Thank you,
Kenny