[Bug] Session Var disable_join_reorder for CREATE TABLE AS SELECT behaves different on master/non-master fe

[dh-cloud]

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• I had searched in the issues and found no similar issues.

Version

2.1.7

What's Wrong?

set disable_join_reorder=true for CREATE TABLE AS SELECT behaves different on master/non-master fe.

On master fe, disable_join_reorder can successfully disable the join reorder.
On non-master fe, disable_join_reorder does not work, joins can be reordered.

What You Expected?

No matter master fe or non-master fe, set disable_join_reorder=true should successfully disable the join reorder for CREATE TABLE AS SELECT. (NOTE: maybe more session variables have the same flaw)

How to Reproduce?

SQLs:

create table t1(id int, dd datetime);
insert into t1 select number, now() from numbers(number = 10000000);

create table t2(id int, dd datetime);
insert into t2 values(1, now());

-- Open  __internal_schema.audit_log
set global enable_audit_plugin = true;

Run on non-master fe::

set disable_join_reorder = true;
set enable_profile=true;
create table tt_notmaster as select t2.id,t1.dd from t2 JOIN t1 on t1.id=t2.id;

Run on master fe:

set disable_join_reorder = true;
set enable_profile=true;
create table tt_master as select t2.id,t1.dd from t2 JOIN t1 on t1.id=t2.id;

Wait a minute...

 select * from __internal_schema.audit_log where stmt like 'create table tt%'

We can see different memory usage:

 peak_memory_bytes: 154994656
 stmt: create table tt_master as select t2.id,t1.dd from t2 JOIN t1 on t1.id=t2.id

 peak_memory_bytes: 2181264
 stmt: create table tt_notmaster as select t2.id,t1.dd from t2 JOIN t1 on t1.id=t2.id

Anything Else?

No response

Are you willing to submit PR?

• Yes I am willing to submit a PR!

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[zclllyybb]

it's easy to fix. you can make a pr which just add needForward=true to disableJoinReorder's VarAttr in SessionVariable.java