BUG #16179: is it reasonable to callback pgss_post_parse_analyze or pg_hint_plan_post_parse_analyze ???

The following bug has been logged on the website:

Bug reference:      16179
Logged by:          DamionZ Zhao
Email address:      zhq651@126.com
PostgreSQL version: 11.5
Operating system:   linux
Description:

When I only configure GUC as shared_preload_libraries = 'pg_hint_plan,
pg_stat_statment'
and have not run sql: 'create extension pg_hint_plan;  create extension
pg_stat_statment',
I expected that parse_analyze will not run into functions
:pgss_post_parse_analyze or pg_hint_plan_post_parse_analyze

In fact , it does not .  I print runtime call stack.
-----------------------------------------------------
statment 1: select 
#0  pgss_post_parse_analyze (pstate=0x2a45818, query=0x2a45928) at
pg_stat_statements.c:812
#1  0x00007fbe60506734 in pg_hint_plan_post_parse_analyze (pstate=0x2a45818,
query=0x2a45928) at pg_hint_plan.c:2767
#2  0x000000000058fbe5 in parse_analyze (parseTree=0x2a45798,
sourceText=0x2a44a90 "select * from abcd;", paramTypes=0x0, numParams=0,
queryEnv=0x0) at analyze.c:124
#3  0x00000000008926b6 in pg_analyze_and_rewrite (parsetree=0x2a45798,
query_string=0x2a44a90 "select * from abcd;", paramTypes=0x0, numParams=0,
queryEnv=0x0)
    at postgres.c:694
#4  0x00000000008938a0 in exec_simple_query (query_string=0x2a44a90 "select
* from abcd;") at postgres.c:1120
#5  0x0000000000897c04 in PostgresMain (argc=1, argv=0x2a73268,
dbname=0x2a73178 "postgres", username=0x2a73158 "postgres") at
postgres.c:4271
#6  0x00000000008021a0 in BackendRun (port=0x2a6b260) at postmaster.c:4405
#7  0x0000000000801934 in BackendStartup (port=0x2a6b260) at
postmaster.c:4077
#8  0x00000000007fe148 in ServerLoop () at postmaster.c:1749
#9  0x00000000007fd936 in PostmasterMain (argc=3, argv=0x2a3cc40) at
postmaster.c:1399
#10 0x0000000000731bab in main (argc=3, argv=0x2a3cc40) at main.c:232
Breakpoint 2, pgss_post_parse_analyze (pstate=0x2a45808, query=0x2a45918) at
pg_stat_statements.c:782
statment 2: create table 
(gdb) bt
#0  pgss_post_parse_analyze (pstate=0x2a45808, query=0x2a45918) at
pg_stat_statements.c:782
#1  0x00007fbe60506734 in pg_hint_plan_post_parse_analyze (pstate=0x2a45808,
query=0x2a45918) at pg_hint_plan.c:2767
#2  0x000000000058fbe5 in parse_analyze (parseTree=0x2a45788,
sourceText=0x2a44a90 "create table abcd\n(i int);", paramTypes=0x0,
numParams=0, queryEnv=0x0)
    at analyze.c:124
#3  0x00000000008926b6 in pg_analyze_and_rewrite (parsetree=0x2a45788,
query_string=0x2a44a90 "create table abcd\n(i int);", paramTypes=0x0,
numParams=0, queryEnv=0x0)
    at postgres.c:694
#4  0x00000000008938a0 in exec_simple_query (query_string=0x2a44a90 "create
table abcd\n(i int);") at postgres.c:1120
#5  0x0000000000897c04 in PostgresMain (argc=1, argv=0x2a73268,
dbname=0x2a73178 "postgres", username=0x2a73158 "postgres") at
postgres.c:4271
#6  0x00000000008021a0 in BackendRun (port=0x2a6b260) at postmaster.c:4405
#7  0x0000000000801934 in BackendStartup (port=0x2a6b260) at
postmaster.c:4077
#8  0x00000000007fe148 in ServerLoop () at postmaster.c:1749
#9  0x00000000007fd936 in PostmasterMain (argc=3, argv=0x2a3cc40) at
postmaster.c:1399
#10 0x0000000000731bab in main (argc=3, argv=0x2a3cc40) at main.c:232
(gdb)

It will degrade performance and may cause the wrong result if it contains
modify operation.