我正在运行一个涉及在 red hat linux 64 位上构建倒排索引的 C++ 程序。我的反转索引被定义为map<unsigned long long int, map<int,int> > invertID;并且我得到了这个错误，它随机崩溃，what(): St9bad_alloc每次崩溃都是不同的。有时，我有 100,000,000 个密钥，但它还能运行一段时间。有时，大约有 80,000,000 个键，它已经喊出了错误。
谷歌搜索，我发现这个错误可能来自new，但是看看我的代码，我没有使用任何new关键字，但是，我有这样的内存分配与 map。我继续在每次迭代中插入键/值对。try catch所以我决定用声明做一些实验。
实际上，这里是代码和输出的关键部分：
map<unsigned long long int, map<int,int> >::iterator mainMapIt = invertID.find(ID);
if (mainMapIt != invertID.end()){
//if this ImageID key exists in InvID sub-map
map<int,int> M = mainMapIt->second; // THIS IS LINE 174.
map<int,int>::iterator subMapIt = M.find(imageID);
if (subMapIt != M.end()){
//increment the number of this ImageID key
++invertID[ID][imageID];
}
else{
//add ImageID key with value 1 into the InvertID
try{
invertID[ID][imageID] = 1;
++totalPushBack;
}catch (bad_alloc ba){
cout << "CAUGHT 1: invertID[" << ID << "][" << imageID << endl;
}
}
}
else{
//create the first empty map with the key as image ID with value 1 and put it in implicitly to the invertID
try{
invertID[ID][imageID] = 1;
}catch (bad_alloc ba){
cout << "CAUGHT 2: invertID[" << ID << "][" << imageID << endl;
}
}
输出：
...
CAUGHT 2: invertID[21959247897][3856
CAUGHT 2: invertID[38022506156][3856
CAUGHT 2: invertID[29062506144][3856
terminate called after throwing an instance of 'std::bad_alloc'
what(): St9bad_alloc
我看到当我尝试插入新密钥时，会抛出错误。然而，在我用块St9bad_alloc盖住钥匙插入部分后，我得到了更多的惊喜。try catch我做了一点回溯，结果如下：
(gdb) backtrace
#0 0x000000344ac30265 in raise () from /lib64/libc.so.6
#1 0x000000344ac31d10 in abort () from /lib64/libc.so.6
#2 0x00000034510becb4 in __gnu_cxx::__verbose_terminate_handler() () from /usr/lib64/libstdc++.so.6
#3 0x00000034510bcdb6 in ?? () from /usr/lib64/libstdc++.so.6
#4 0x00000034510bcde3 in std::terminate() () from /usr/lib64/libstdc++.so.6
#5 0x00000034510bceca in __cxa_throw () from /usr/lib64/libstdc++.so.6
#6 0x00000034510bd1d9 in operator new(unsigned long) () from /usr/lib64/libstdc++.so.6
#7 0x0000000000406544 in __gnu_cxx::new_allocator<std::_Rb_tree_node<std::pair<int const, int> > >::allocate (
this=0x7fffffffdfc0, __n=1)
at /usr/lib/gcc/x86_64-redhat-linux/4.1.2/../../../../include/c++/4.1.2/ext/new_allocator.h:88
#8 0x0000000000406568 in std::_Rb_tree<int, std::pair<int const, int>, std::_Select1st<std::pair<int const, int> >, std::less<int>, std::allocator<std::pair<int const, int> > >::_M_get_node (this=0x7fffffffdfc0)
at /usr/lib/gcc/x86_64-redhat-linux/4.1.2/../../../../include/c++/4.1.2/bits/stl_tree.h:358
#9 0x0000000000406584 in std::_Rb_tree<int, std::pair<int const, int>, std::_Select1st<std::pair<int const, int> >, std::less<int>, std::allocator<std::pair<int const, int> > >::_M_create_node (this=0x7fffffffdfc0, __x=...)
at /usr/lib/gcc/x86_64-redhat-linux/4.1.2/../../../../include/c++/4.1.2/bits/stl_tree.h:367
#10 0x00000000004065e3 in std::_Rb_tree<int, std::pair<int const, int>, std::_Select1st<std::pair<int const, int> >, std::less<int>, std::allocator<std::pair<int const, int> > >::_M_clone_node (this=0x7fffffffdfc0, __x=0x21c082bd0)
at /usr/lib/gcc/x86_64-redhat-linux/4.1.2/../../../../include/c++/4.1.2/bits/stl_tree.h:381
#11 0x0000000000406634 in std::_Rb_tree<int, std::pair<int const, int>, std::_Select1st<std::pair<int const, int> >, std::less<int>, std::allocator<std::pair<int const, int> > >::_M_copy (this=0x7fffffffdfc0, __x=0x21c082bd0, __p=0x7fffffffdfc8)
at /usr/lib/gcc/x86_64-redhat-linux/4.1.2/../../../../include/c++/4.1.2/bits/stl_tree.h:1226
#12 0x00000000004067e9 in std::_Rb_tree<int, std::pair<int const, int>, std::_Select1st<std::pair<int const, int> >, std::less<int>, std::allocator<std::pair<int const, int> > >::_Rb_tree (this=0x7fffffffdfc0, __x=...)
at /usr/lib/gcc/x86_64-redhat-linux/4.1.2/../../../../include/c++/4.1.2/bits/stl_tree.h:570
#13 0x0000000000406885 in std::map<int, int, std::less<int>, std::allocator<std::pair<int const, int> > >::map (
this=0x7fffffffdfc0, __x=...) at /usr/lib/gcc/x86_64-redhat-linux/4.1.2/../../../../include/c++/4.1.2/bits/stl_map.h:175
#14 0x0000000000403039 in generateInvertID (pathToPF=0x6859a8 "/home/karl/c/000605.pf",
pathToC=0x38c139ed8 "/home/karl/c/000605.c", imageID=3856)
at InvertIndexGen.cpp:174
#15 0x0000000000403b46 in generateInvertIDForAllPFAndC () at InvertIndexGen.cpp:254
#16 0x0000000000403d0b in main (argc=1, argv=0x7fffffffe448) at InvertIndexGen.cpp:47
(gdb)
在 #14，InvertIndexGen.cpp:174，在我上面的代码中，这是它崩溃的地方：
map<int,int> M = mainMapIt->second; // THIS IS LINE 174.
似乎当我调用时->second，必须创建相应地图的副本。这应该也是原因St9bad_alloc。
但是在这种情况下，我可以在这里做些什么吗？毕竟，invertID.max_size()返回 18446744073709551615，而我只使用了大约 1 亿个密钥。我也从 中看到top，我的程序只使用了 10% 的内存。（我们有 128GB 内存）
我应该对这个错误采取哪些措施？我看到我的一些高级同事也在这样做，他们报告说，当他们的反转索引开始增长超过 70-80% 的内存时top，程序开始出现问题。但是我的程序只使用了 10%，那么这里发生了什么？我们可以做些什么来防止这个错误？
编辑：一些评论建议我检查一下ulimit，所以这里是：
-bash-3.2$ ulimit -a
core file size (blocks, -c) 0
data seg size (kbytes, -d) unlimited
scheduling priority (-e) 0
file size (blocks, -f) unlimited
pending signals (-i) 1056768
max locked memory (kbytes, -l) 32
max memory size (kbytes, -m) unlimited
open files (-n) 1024
pipe size (512 bytes, -p) 8
POSIX message queues (bytes, -q) 819200
real-time priority (-r) 0
stack size (kbytes, -s) 10240
cpu time (seconds, -t) unlimited
max user processes (-u) 1056768
virtual memory (kbytes, -v) unlimited
file locks (-x) unlimited