[Postgres-xc-developers] May be a bug!

Dears,
 
Maybe a bug. My test environment:two coordinators, two datanodes.The steps are described as follows:
1. create table tt(a int);
2. alter table tt add constraint pk primary key(a);
3. insert into tt values(8);
4. insert into tt values(8);
when execute step 4, something happened.
 
coordinator log:
template1=# insert into tt values(8);
INSERT 0 1
template1=# insert into tt values(8);
WARNING:  unexpected EOF on datanode connection
ERROR:  Failed to read response from data nodes
STATEMENT:  insert into tt values(8);
WARNING:  unexpected EOF on datanode connection
WARNING:  unexpected EOF on datanode connection
WARNING:  unexpected EOF on datanode connection
ERROR:  Failed to read response from data nodes
template1=# LOG:  failed to connect to data node
LOG:  failed to connect to data node
 
Two datanodes' logs are described respectively.
local one:
LOG:  statement: BEGIN
LOG:  statement: insert into tt values(8);
LOG:  statement: PREPARE TRANSACTION 'T116'
LOG:  statement: COMMIT PREPARED 'T116'
LOG:  statement: BEGIN
LOG:  statement: insert into tt values(8);
ERROR:  duplicate key value violates unique constraint "pk"
STATEMENT:  insert into tt values(8);
PANIC:  cannot abort transaction 118, it was already committed
LOG:  server process (PID 1374) was terminated by signal 6: Aborted
LOG:  terminating any other active server processes
LOG:  all server processes terminated; reinitializing
LOG:  database system was interrupted; last known up at 2010-10-19 14:30:31 CST
LOG:  database system was not properly shut down; automatic recovery in progress
The session started: 1376
FATAL:  the database system is in recovery mode
LOG:  redo starts at 0/4BC07C
LOG:  record with zero length at 0/4BC408
LOG:  redo done at 0/4BC3DC
LOG:  last completed transaction was at log time 2021-08-06 21:02:14.101545+08
LOG:  autovacuum launcher started
LOG:  database system is ready to accept connections
 
The remote datanode log:
LOG:  statement: BEGIN
LOG:  statement: insert into tt values(8);
LOG:  statement: PREPARE TRANSACTION 'T116'
LOG:  statement: COMMIT PREPARED 'T116'
LOG:  statement: BEGIN
LOG:  statement: insert into tt values(8);
LOG:  statement: ROLLBACK
PANIC:  cannot abort transaction 118, it was already committed
STATEMENT:  ROLLBACK
LOG:  server process (PID 28899) was terminated by signal 6: Aborted
LOG:  terminating any other active server processes
LOG:  all server processes terminated; reinitializing
LOG:  database system was interrupted; last known up at 2010-10-19 14:29:49 CST
LOG:  database system was not properly shut down; automatic recovery in progress
The session started: 28901
FATAL:  the database system is in recovery mode
LOG:  redo starts at 0/712738
LOG:  record with zero length at 0/712A44
LOG:  redo done at 0/712A18
LOG:  last completed transaction was at log time 2021-08-06 21:01:31.960109+08
LOG:  autovacuum launcher started
LOG:  database system is ready to accept connections
 
                                                                                  Truely,
                                                                                   Benny