C++ 内存泄漏排查实战¶
regression=# SELECT t1.a, t1.c, t2.b, t2.c FROM prt1_e t1, prt2_e t2 WHERE (t1.a + t1.b)/2 = (t2.b + t2.a)/2 AND t1.c = 0 ORDER BY t1.a, t2.b;
WARNING: problem in alloc set ExecutorState: bad single-chunk 0x7cfdd48 in block 0x7cfc580 (seg1 slice1 127.0.1.1:7003 pid=4295)
WARNING: problem in alloc set ExecutorState: found inconsistent memory block 0x7cfc580 (seg1 slice1 127.0.1.1:7003 pid=4295)
WARNING: problem in alloc set ExecutorState: bad single-chunk 0x7cfdd48 in block 0x7cfc580 (seg1 slice1 127.0.1.1:7003 pid=4295)
WARNING: problem in alloc set ExecutorState: found inconsistent memory block 0x7cfc580 (seg1 slice1 127.0.1.1:7003 pid=4295)
WARNING: problem in alloc set ExecutorState: bad single-chunk 0x87f85c8 in block 0x87f6e00 (seg0 slice1 127.0.1.1:7002 pid=4294)
WARNING: problem in alloc set ExecutorState: found inconsistent memory block 0x87f6e00 (seg0 slice1 127.0.1.1:7002 pid=4294)
WARNING: problem in alloc set ExecutorState: bad single-chunk 0x7d3c5c8 in block 0x7d3ae00 (seg2 slice1 127.0.1.1:7004 pid=4296)
WARNING: problem in alloc set ExecutorState: found inconsistent memory block 0x7d3ae00 (seg2 slice1 127.0.1.1:7004 pid=4296)
WARNING: problem in alloc set ExecutorState: bad single-chunk 0x87f85c8 in block 0x87f6e00 (seg0 slice1 127.0.1.1:7002 pid=4294)
WARNING: problem in alloc set ExecutorState: bad single-chunk 0x7d3c5c8 in block 0x7d3ae00 (seg2 slice1 127.0.1.1:7004 pid=4296)
WARNING: problem in alloc set ExecutorState: found inconsistent memory block 0x87f6e00 (seg0 slice1 127.0.1.1:7002 pid=4294)
WARNING: problem in alloc set ExecutorState: found inconsistent memory block 0x7d3ae00 (seg2 slice1 127.0.1.1:7004 pid=4296)
调试：
(gdb) b aset.c:1109 if chunk=0x7cfdd48
Breakpoint 1 at 0x105d420: file aset.c, line 1109.
(gdb) c
Continuing.
Thread 1 "postgres" hit Breakpoint 1, AllocSetAlloc (context=0x787ac50, size=4096) at aset.c:1109
1109 block->freeptr += (chunk_size + ALLOC_CHUNKHDRSZ);
(gdb) p chunk
$1 = (AllocChunk) 0x7cfdd48
(gdb) p chunk->size
$2 = 9187201950435737471
(gdb) p &chunk->size
$3 = (Size *) 0x7cfdd48
(gdb) watch (*((Size *) 0x7cfdd48))
Hardware watchpoint 2: (*((Size *) 0x7cfdd48))
(gdb) i b
Num Type Disp Enb Address What
1 breakpoint keep y 0x000000000105d420 in AllocSetAlloc at aset.c:1109
stop only if chunk=0x7cfdd48
breakpoint already hit 1 time
2 hw watchpoint keep y (*((Size *) 0x7cfdd48))
(gdb) d 1
(gdb) c