Re: Out of Memory errors are frustrating as heck!

After applying Tomas' corrected patch 0001, and routing HJDEBUG messages 
to stderr:

integrator=# set enable_nestloop to off;
SET
integrator=# explain analyze select * from reports.v_BusinessOperation;
WARNING:  ExecHashIncreaseNumBatches: increasing number of batches from 16 to 32
WARNING:  ExecHashIncreaseNumBatches: increasing number of batches from 32 to 64
WARNING:  ExecHashIncreaseNumBatches: increasing number of batches from 64 to 128
WARNING:  ExecHashIncreaseNumBatches: increasing number of batches from 128 to 256
WARNING:  ExecHashIncreaseNumBatches: increasing number of batches from 256 to 512
WARNING:  ExecHashIncreaseNumBatches: increasing number of batches from 512 to 1024
WARNING:  ExecHashIncreaseNumBatches: increasing number of batches from 1024 to 2048
WARNING:  ExecHashIncreaseNumBatches: increasing number of batches from 2048 to 4096
WARNING:  ExecHashIncreaseNumBatches: increasing number of batches from 4096 to 8192
WARNING:  ExecHashIncreaseNumBatches: increasing number of batches from 8192 to 16384
WARNING:  ExecHashIncreaseNumBatches: increasing number of batches from 16384 to 32768
WARNING:  ExecHashIncreaseNumBatches: increasing number of batches from 32768 to 65536
WARNING:  ExecHashIncreaseNumBatches: increasing number of batches from 65536 to 131072
WARNING:  ExecHashIncreaseNumBatches: increasing number of batches from 131072 to 262144
WARNING:  ExecHashIncreaseNumBatches: increasing number of batches from 262144 to 524288
ERROR:  out of memory
DETAIL:  Failed on request of size 32800 in memory context "HashBatchContext".

Now

TopMemoryContext: 4347672 total in 9 blocks; 41688 free (18 chunks); 4305984 used
   HandleParallelMessages: 8192 total in 1 blocks; 7936 free (0 chunks); 256 used
   TableSpace cache: 8192 total in 1 blocks; 2096 free (0 chunks); 6096 used
   Type information cache: 24352 total in 2 blocks; 2624 free (0 chunks); 21728 used
   pgstat TabStatusArray lookup hash table: 8192 total in 1 blocks; 416 free (0 chunks); 7776 used
   TopTransactionContext: 8192 total in 1 blocks; 5416 free (2 chunks); 2776 used
   RowDescriptionContext: 8192 total in 1 blocks; 6896 free (0 chunks); 1296 used
   MessageContext: 32768 total in 3 blocks; 13488 free (10 chunks); 19280 used
   Operator class cache: 8192 total in 1 blocks; 560 free (0 chunks); 7632 used
   smgr relation table: 32768 total in 3 blocks; 16832 free (8 chunks); 15936 used
   TransactionAbortContext: 32768 total in 1 blocks; 32512 free (0 chunks); 256 used
   Portal hash: 8192 total in 1 blocks; 560 free (0 chunks); 7632 used
   TopPortalContext: 8192 total in 1 blocks; 7664 free (0 chunks); 528 used
     PortalHoldContext: 24632 total in 2 blocks; 7392 free (0 chunks); 17240 used
     PortalContext: 1482752 total in 184 blocks; 11216 free (8 chunks); 1471536 used:
       ExecutorState: 2449896 total in 16 blocks; 1795000 free (3158 chunks); 654896 used
         HashBatchFiles: 8192 total in 1 blocks; 7936 free (0 chunks); 256 used
         HashTableContext: 16384 total in 2 blocks; 3008 free (6 chunks); 13376 used
           HashBatchContext: 8192 total in 1 blocks; 7936 free (0 chunks); 256 used
         HashBatchFiles: 8192 total in 1 blocks; 7936 free (0 chunks); 256 used
         HashTableContext: 8192 total in 1 blocks; 7320 free (0 chunks); 872 used
           HashBatchContext: 8192 total in 1 blocks; 7936 free (0 chunks); 256 used
         HashBatchFiles: 8192 total in 1 blocks; 7936 free (0 chunks); 256 used
         HashTableContext: 8192 total in 1 blocks; 7320 free (0 chunks); 872 used
           HashBatchContext: 8192 total in 1 blocks; 7936 free (0 chunks); 256 used
         HashBatchFiles: 8192 total in 1 blocks; 7936 free (0 chunks); 256 used
         HashTableContext: 8192 total in 1 blocks; 7752 free (0 chunks); 440 used
           HashBatchContext: 90288 total in 4 blocks; 16072 free (6 chunks); 74216 used
         HashBatchFiles: 8192 total in 1 blocks; 7936 free (0 chunks); 256 used
         HashTableContext: 8192 total in 1 blocks; 7624 free (0 chunks); 568 used
           HashBatchContext: 90288 total in 4 blocks; 16072 free (6 chunks); 74216 used
         TupleSort main: 1073512 total in 11 blocks; 246792 free (39 chunks); 826720 used
         TupleSort main: 286912 total in 8 blocks; 246792 free (39 chunks); 40120 used
         ExprContext: 8192 total in 1 blocks; 7936 free (0 chunks); 256 used
         HashBatchFiles: 2242545904 total in 266270 blocks; 3996232 free (14164 chunks); 2238549672 used
         HashTableContext: 8192 total in 1 blocks; 7624 free (5 chunks); 568 used
           HashBatchContext: 168165080 total in 5118 blocks; 7936 free (0 chunks); 168157144 used
         TupleSort main: 452880 total in 8 blocks; 126248 free (27 chunks); 326632 used
           Caller tuples: 1048576 total in 8 blocks; 21608 free (14 chunks); 1026968 used
         ExprContext: 8192 total in 1 blocks; 7936 free (0 chunks); 256 used
         ExprContext: 8192 total in 1 blocks; 7936 free (0 chunks); 256 used
         ExprContext: 8192 total in 1 blocks; 7936 free (0 chunks); 256 used
         ExprContext: 8192 total in 1 blocks; 7936 free (0 chunks); 256 used
         ExprContext: 8192 total in 1 blocks; 7936 free (0 chunks); 256 used
         ExprContext: 8192 total in 1 blocks; 7936 free (0 chunks); 256 used
         ExprContext: 8192 total in 1 blocks; 7936 free (0 chunks); 256 used
         ExprContext: 8192 total in 1 blocks; 7936 free (0 chunks); 256 used
         ExprContext: 8192 total in 1 blocks; 7936 free (0 chunks); 256 used
         ExprContext: 8192 total in 1 blocks; 7936 free (0 chunks); 256 used
         ExprContext: 8192 total in 1 blocks; 7936 free (0 chunks); 256 used
         ExprContext: 8192 total in 1 blocks; 7936 free (0 chunks); 256 used
         ExprContext: 8192 total in 1 blocks; 7936 free (0 chunks); 256 used
         ExprContext: 8192 total in 1 blocks; 7936 free (0 chunks); 256 used
         ExprContext: 8192 total in 1 blocks; 7936 free (0 chunks); 256 used
         ExprContext: 8192 total in 1 blocks; 7936 free (0 chunks); 256 used
         ExprContext: 8192 total in 1 blocks; 7936 free (0 chunks); 256 used
         ExprContext: 8192 total in 1 blocks; 7936 free (0 chunks); 256 used
         ExprContext: 8192 total in 1 blocks; 7936 free (0 chunks); 256 used
         ExprContext: 8192 total in 1 blocks; 7936 free (0 chunks); 256 used
         ExprContext: 8192 total in 1 blocks; 7936 free (0 chunks); 256 used
         ExprContext: 8192 total in 1 blocks; 7936 free (0 chunks); 256 used
         ExprContext: 8192 total in 1 blocks; 7936 free (0 chunks); 256 used
         ExprContext: 8192 total in 1 blocks; 7936 free (0 chunks); 256 used
         ExprContext: 8192 total in 1 blocks; 7936 free (0 chunks); 256 used
         ExprContext: 8192 total in 1 blocks; 7936 free (0 chunks); 256 used
         ExprContext: 8192 total in 1 blocks; 7936 free (0 chunks); 256 used
   Relcache by OID: 16384 total in 2 blocks; 3512 free (2 chunks); 12872 used
   CacheMemoryContext: 1101328 total in 14 blocks; 288672 free (1 chunks); 812656 used
     index info: 2048 total in 2 blocks; 680 free (1 chunks); 1368 used: pg_toast_2619_index
     index info: 2048 total in 2 blocks; 968 free (1 chunks); 1080 used: entity_id_fkidx
...
     index info: 2048 total in 2 blocks; 680 free (1 chunks); 1368 used: pg_attribute_relid_attnum_index
     index info: 2048 total in 2 blocks; 952 free (1 chunks); 1096 used: pg_class_oid_index
   WAL record construction: 49768 total in 2 blocks; 6368 free (0 chunks); 43400 used
   PrivateRefCount: 8192 total in 1 blocks; 2624 free (0 chunks); 5568 used
   MdSmgr: 8192 total in 1 blocks; 6560 free (1 chunks); 1632 used
   LOCALLOCK hash: 16384 total in 2 blocks; 4600 free (2 chunks); 11784 used
   Timezones: 104120 total in 2 blocks; 2624 free (0 chunks); 101496 used
   ErrorContext: 8192 total in 1 blocks; 7936 free (5 chunks); 256 used
Grand total: 2424300520 bytes in 271910 blocks; 7332360 free (17596 chunks); 2416968160 used
2019-04-21 19:50:21.338 UTC [6974] ERROR:  out of memory
2019-04-21 19:50:21.338 UTC [6974] DETAIL:  Failed on request of size 32800 in memory context "HashBatchContext".
2019-04-21 19:50:21.338 UTC [6974] STATEMENT:  explain analyze select * from reports.v_BusinessOperation;

Next I'll apply Tomas' corrected 0002 patch on top of this and see ...

-Gunther