1.函数调用过程
exec_simple_query
---- PortalDrop -写入到了xlog文件
---- finish_xact_command
---- EndCommand -写入到了xlog文件
---- finish_xact_command
#0 PageAddItem at bufpage.c:353
#1 0x00000000004b56f4 in RelationPutHeapTuple at hio.c:53
#2 0x00000000004aa194 in heap_insert at heapam.c:2417
#3 0x000000000066ed2a in ExecInsert at nodeModifyTable.c:490
#4 0x00000000006703fa in ExecModifyTable at nodeModifyTable.c:1511
#6 0x0000000000646645 in ExecutePlan at execMain.c:1569
#7 0x0000000000644903 in standard_ExecutorRun at execMain.c:338
#8 0x00000000006447e1 in ExecutorRun at execMain.c:286
#9 0x00000000007cb712 in ProcessQuery at pquery.c:187
#10 0x00000000007cce49 in PortalRunMulti at pquery.c:1303
#11 0x00000000007cc457 in PortalRun at pquery.c:815
#12 0x00000000007c6845 in exec_simple_query at pquery.c:815
#12 0x00000000007c6845 in exec_simple_query at postgres.c:1094
#13 0x00000000007ca81a in PostgresMain at postgres.c:4076
#14 0x000000000074d0d2 in BackendRun (port=0x127a550) at postmaster.c:4271
#15 0x000000000074c85e in BackendStartup (port=0x127a550) at postmaster.c:3945
#16 0x00000000007491e1 in ServerLoop () at postmaster.c:1701
#17 0x00000000007488ed in PostmasterMain (argc=1, argv=0x1252d20) at postmaster.c:1309
#18 0x0000000000699702 in main (argc=1, argv=0x1252d20) at main.c:228
#0 0x00000000007a0455 in WaitEventSetWaitBlock (set=0x19a1d30, cur_timeout=-1, occurred_events=0x7fffecea8440, nevents=1) at latch.c:990
#1 0x00000000007a0321 in WaitEventSetWait (set=0x19a1d30, timeout=-1, occurred_events=0x7fffecea8440, nevents=1) at latch.c:944
#2 0x000000000068b658 in secure_read (port=0x19c7550, ptr=0xd86d80, len=8192) at be-secure.c:149
#3 0x0000000000696b13 in pq_recvbuf () at pqcomm.c:921
#4 0x0000000000696ba9 in pq_getbyte () at pqcomm.c:964
#5 0x00000000007c5b37 in SocketBackend (inBuf=0x7fffecea8650) at postgres.c:334
#6 0x00000000007c600f in ReadCommand (inBuf=0x7fffecea8650) at postgres.c:507
#7 0x00000000007ca74c in PostgresMain (argc=1, argv=0x19c9dd8, dbname=0x19c9cc0 "testdb", username=0x19c9ca0 "postgres")
#8 0x000000000074d0d2 in BackendRun (port=0x19c7550) at postmaster.c:4271
#9 0x000000000074c85e in BackendStartup (port=0x19c7550) at postmaster.c:3945
#10 0x00000000007491e1 in ServerLoop () at postmaster.c:1701
#11 0x00000000007488ed in PostmasterMain (argc=1, argv=0x199fd20) at postmaster.c:1309#12 0x0000000000699702 in main (argc=1, argv=0x199fd20) at main.c:228
内存刷入外存参考（mdimmedsync：刷出一个“relation”的内容到外存）
https://blog.csdn.net/fly2nn/article/details/61924248
问题：为什么gdb无法进入epoll_wait中的方法
备注：
set print frame-arguments scalars // 有三种值，all/scalars/none，默认是al
