Abdul Yadi: BDR 0.9.3 Crashes and Index on Expression

Giving BDR version 0.9.3 and patched-PostgreSQL 9.4.5 replication a shot. All runs smooth until I add an index expression to a replicated table then insert a record into. BDR crashes with error message:

LOG: worker process: bdr (6229655055721591121,1,16386,)->bdr (6229655055721591121,1, (PID 750) was terminated by signal 11: Segmentation fault
DETAIL: Failed process was running: bdr_apply: BEGIN origin(source, orig_lsn, timestamp): 0/9D50AD0, 2015-12-27 10:13:29.916096+07

Followed by series of:
FATAL: mismatch in worker state, got 0, expected 1

Dig into BDR C codes, I found out that the error is emitted from a point in bdr_apply.c:

function: process_remote_insert
simple_heap_insert(rel->rel, newslot->tts_tuple); --ok
UserTableUpdateOpenIndexes(estate, newslot); --failed


Go deeper into BDR-patched-PostgreSQL’s index.c, it is clear that BDR only crashes when updating index on expression (no problem with column index).

function: FormIndexDatum
iDatum = slot_getattr(slot, keycol, &isNull); --ok
but
iDatum = ExecEvalExprSwitchContext((ExprState *) lfirst(indexpr_item), GetPerTupleExprContext(estate),&isNull,NULL); --failed

Simple solution is removing the index expression and promote field (or new field) for regular column index instead.