Re: [HACKERS] Parallel Bitmap scans a bit broken

> Are you getting the crash with the same test case?

Yes.  Here is the new backtrace:

> * thread #1: tid = 0x51828fd, 0x0000000100caf314 postgres`tbm_prepare_shared_iterate [inlined] pg_atomic_write_u32_impl(val=0) at generic.h:57, queue = 'com.apple.main-thread', stop reason = EXC_BAD_ACCESS (code=1, address=0x0)
>   * frame #0: 0x0000000100caf314 postgres`tbm_prepare_shared_iterate [inlined] pg_atomic_write_u32_impl(val=0) at generic.h:57 [opt]
>     frame #1: 0x0000000100caf314 postgres`tbm_prepare_shared_iterate [inlined] pg_atomic_init_u32_impl(val_=0) at generic.h:163 [opt]
>     frame #2: 0x0000000100caf314 postgres`tbm_prepare_shared_iterate [inlined] pg_atomic_init_u32(val=0) + 17 at atomics.h:237 [opt]
>     frame #3: 0x0000000100caf303 postgres`tbm_prepare_shared_iterate(tbm=) + 723 at tidbitmap.c:875 [opt]
>     frame #4: 0x0000000100c74844 postgres`BitmapHeapNext(node=) + 436 at nodeBitmapHeapscan.c:154 [opt]
>     frame #5: 0x0000000100c615b0 postgres`ExecProcNode(node=0x00007fdabf8189f0) + 224 at execProcnode.c:459 [opt]
>     frame #6: 0x0000000100c76ca9 postgres`ExecGather [inlined] gather_getnext(gatherstate=) + 520 at nodeGather.c:276 [opt]
>     frame #7: 0x0000000100c76aa1 postgres`ExecGather(node=) + 497 at nodeGather.c:212 [opt]
>     frame #8: 0x0000000100c61692 postgres`ExecProcNode(node=0x00007fdabf818558) + 450 at execProcnode.c:541 [opt]
>     frame #9: 0x0000000100c5cf70 postgres`standard_ExecutorRun [inlined] ExecutePlan(estate=, planstate=, use_parallel_mode=, operation=, numberTuples=0, direction=, dest=) + 29 at execMain.c:1616 [opt]
>    frame #10: 0x0000000100c5cf53 postgres`standard_ExecutorRun(queryDesc=, direction=, count=0) + 291 at execMain.c:348 [opt]
>    frame #11: 0x0000000100dac0df postgres`PortalRunSelect(portal=0x00007fdac000b240, forward=, count=0, dest=) + 255 at pquery.c:921 [opt]
>    frame #12: 0x0000000100dabc84 postgres`PortalRun(portal=0x00007fdac000b240, count=, isTopLevel='\x01', dest=, altdest=, completionTag=) + 500 at pquery.c:762 [opt]
>    frame #13: 0x0000000100da989b postgres`PostgresMain + 44 at postgres.c:1101 [opt]
>    frame #14: 0x0000000100da986f postgres`PostgresMain(argc=, argv=, dbname=, username=) + 8927 at postgres.c:4066 [opt]
>    frame #15: 0x0000000100d2c113 postgres`PostmasterMain [inlined] BackendRun + 7587 at postmaster.c:4317 [opt]
>    frame #16: 0x0000000100d2c0e8 postgres`PostmasterMain [inlined] BackendStartup at postmaster.c:3989 [opt]
>    frame #17: 0x0000000100d2c0e8 postgres`PostmasterMain at postmaster.c:1729 [opt]
>    frame #18: 0x0000000100d2c0e8 postgres`PostmasterMain(argc=, argv=) + 7544 at postmaster.c:1337 [opt]
>    frame #19: 0x0000000100ca528f postgres`main(argc=, argv=) + 1567 at main.c:228 [opt]
>    frame #20: 0x00007fffb4e28255 libdyld.dylib`start + 1
>    frame #21: 0x00007fffb4e28255 libdyld.dylib`start + 1