There seems to be a problem in behavior of Create Index Concurrently and Hot Update in HEAD code . Please see the below testcase
Step-1 ----------- Client-1 Create table t1(c1 int, c2 int, c3 int); insert into t1 values(1,2,3); Step-2 ----------- Client - 2 update t1 set c2=4; where c1 = 1; -- This will be Hot update Select * from t1; c1 | c2 | c3 ----+----+---- 1 | 4 | 3 (1 row) No problem till here. Step-3 ----------- Client -1 create index concurrently idx_conc_t1 on t1(c2); -- Run this command in debug mode (by having breakpoint in DefineIndex) Stop before the CommitTransactionCommand() of phase-2 where index_build is done and indisready flag is set to TRUE. As we have stopped before commit, still indexisready will not be visible to other session/transaction. Step-4 ----------- Client -2 update t1 set c2=5 where c1=1; -- Update is success, but this is a HOT update According to me, here is the problem, it shouldn't have done HOT update. Step-5 ----------- Client-1 Resume debugging, and complete the command. I have observed in validate_index(), it doesn't create index entry for c2=5. Step-6 ----------- Client-2 select * from t1 where c2=5; c1 | c2 | c3 ----+----+---- 1 | 5 | 3 (1 row) postgres=# set enable_seqscan=off; -- This is to ensure index scan should happen SET postgres=# select * from t1 where c2=5; -- Problem, it should have shown the Row. c1 | c2 | c3 ----+----+---- (0 rows) postgres=# select * from t1 where c2=4; -- Problem, query is done for C2=4 and the result shows C2=5. c1 | c2 | c3 ----+----+---- 1 | 5 | 3 (1 row) According to me, the problem happens at Step-4. As at Step-4, it does the HOT update due to which validate_index() is not able to put an entry for C2=5 Let me know if I have misunderstood something? With Regards, Amit Kapila.
