Re: "ERROR: could not open relation with OID 16391" error was encountered when reindexing

I have provided a python script in the attachment to minimize the reproduction of the issue.

I'm sorry that I lost the attached script in my last reply, but I've added it in this reply.

You can also use psql to reproduce it with the following steps:
1. Initialize the data
```
DROP TABLE IF EXISTS tbl_part;
CREATE TABLE tbl_part (a integer) PARTITION BY RANGE (a);
CREATE TABLE tbl_part_p1 PARTITION OF tbl_part FOR VALUES FROM (0) TO (10);
CREATE INDEX ON tbl_part(a);
```
2. session1 reindex and gdb break at index.c:3585
```
REINDEX INDEX tbl_part_a_idx;
```
3. session2 drop index succeed

```
DROP INDEX tbl_part_a_idx;
```
4. session1 gdb continue

Best Regards,
Fei Changhong
Alibaba Cloud Computing Ltd.