MySQL 错误 1436:线程堆栈溢出，带有简单查询

2021-11-20 00:00:00 mysql triggers

我正在对表做一个非常简单的更新，这也触发了一个非常简单的触发器，它给了我错误

I am doing a very simple update on a table, which also triggers a really simple trigger, and it gives me the error

#1436 - Thread stack overrun:  6136 bytes used of a 131072 byte stack, and 128000 bytes needed.

我执行的查询:

UPDATE field_values SET value = 'asaf' WHERE field_values.id =1

值字段是一个 text 字段.所以理论上它可以变得安静大.在这种情况下，情况并非如此.

The value field is a text field. So in theory it could become quiet big. Which is not the case in this situation.

正在执行的触发器是:

DELIMITER $$
    CREATE TRIGGER field_value_update_trigger BEFORE UPDATE ON community_fields_values
    FOR EACH ROW BEGIN
      INSERT INTO user_field_log (user_id, field_id, value) VALUES (NEW.user_id, NEW.field_id, NEW.value);
    END;
$$
DELIMITER ;

为什么会显示此错误?这不像涉及任何繁重的查询.还要注意，数据库几乎是空的，community_fields_values 中只有 2 行，user_field_log

Why is this error showing? It's not like there is any heavy query involved. Also note that the database is almost empty, just 2 rows in community_fields_values and no rows in the user_field_log

MySQL 版本:5.1.44

MySQL version: 5.1.44

推荐答案

1436 - 线程堆栈溢出:131072 字节堆栈中使用了 6136 字节，需要 128000 字节.

错误1436对应mysql 5.1代码中的ER_STACK_OVERRUN_NEED_MORE:

1436 - Thread stack overrun: 6136 bytes used of a 131072 byte stack, and 128000 bytes needed.

The error 1436 corresponds to ER_STACK_OVERRUN_NEED_MORE in the mysql 5.1 code :

malff@linux-8edv:include> pwd
/home/malff/BZR_TREE/mysql-5.1/include
malff@linux-8edv:include> grep 1436 mysqld_error.h
#define ER_STACK_OVERRUN_NEED_MORE 1436

打印所见错误的代码在 sql/sql_parse.cc 中，函数 check_stack_overrun() :

The code printing the error seen is in sql/sql_parse.cc, function check_stack_overrun() :

bool check_stack_overrun(THD *thd, long margin,
                         uchar *buf __attribute__((unused)))
{
  long stack_used;
  DBUG_ASSERT(thd == current_thd);
  if ((stack_used=used_stack(thd->thread_stack,(char*) &stack_used)) >=
      (long) (my_thread_stack_size - margin))
  {
    char ebuff[MYSQL_ERRMSG_SIZE];
    my_snprintf(ebuff, sizeof(ebuff), ER(ER_STACK_OVERRUN_NEED_MORE),
                stack_used, my_thread_stack_size, margin);
    my_message(ER_STACK_OVERRUN_NEED_MORE, ebuff, MYF(ME_FATALERROR));

从看到的值来看，margin 是 128000，my_thread_stack_size 是 131072.

From the values seen, margin is 128000, and my_thread_stack_size is 131072.

对 check_stack_overrun() 试图保留 128000 字节的唯一调用来自:

The only call to check_stack_overrun() that tries to reserve 128000 bytes is from:

bool
sp_head::execute(THD *thd)
{
  /* Use some extra margin for possible SP recursion and functions */
  if (check_stack_overrun(thd, 8 * STACK_MIN_SIZE, (uchar*)&old_packet))
    DBUG_RETURN(TRUE);

STACK_MIN_SIZE 的值为 16000:

The value of STACK_MIN_SIZE is 16000:

malff@linux-8edv:sql> pwd
/home/malff/BZR_TREE/mysql-5.1/sql
malff@linux-8edv:sql> grep STACK_MIN_SIZE *.h
mysql_priv.h:#define STACK_MIN_SIZE          16000   // Abort if less stack during eval.

到目前为止，服务器一切正常:

So far, everything works as expected for the server:

  • 代码执行一个触发器，它是用sp_head::execute.
  • MySQL 运行时检查堆栈上是否至少有 128000 个字节
  • 此检查失败(理应如此)，触发器执行以错误结束.

MySQL 触发器执行所需的堆栈数量不取决于触发器复杂性本身，或所涉及表的内容/结构.

The amount of stack needed by the MySQL trigger execution does not depends on the trigger complexity itself, or the content / structure of the tables involved.

真正的问题是什么，我猜，为什么 thread_stack 只有 128K (131072).

What the real question is, I guess, why is the thread_stack only at 128K (131072).

名为 'thread_stack' 的服务器变量在 C 中实现为 sql/mysqld.cc 中的 'my_thread_stack_size' :

The server variable named 'thread_stack' is implemented in C as 'my_thread_stack_size' in sql/mysqld.cc :

  {"thread_stack", OPT_THREAD_STACK,
   "The stack size for each thread.", &my_thread_stack_size,
   &my_thread_stack_size, 0, GET_ULONG, REQUIRED_ARG,DEFAULT_THREAD_STACK,
   1024L*128L, ULONG_MAX, 0, 1024, 0},

1024L*128L 是此参数的最小值.默认值为DEFAULT_THREAD_STACK，定义在include/my_pthread.h:

1024L*128L is the minimum value for this parameter. The default value is DEFAULT_THREAD_STACK, which is defined in include/my_pthread.h:

#ifndef DEFAULT_THREAD_STACK
#if SIZEOF_CHARP > 4
/*
  MySQL can survive with 32K, but some glibc libraries require > 128K stack
  To resolve hostnames. Also recursive stored procedures needs stack.
*/
#define DEFAULT_THREAD_STACK    (256*1024L)
#else
#define DEFAULT_THREAD_STACK    (192*1024)
#endif
#endif

因此，默认情况下，堆栈大小应为 192K(32 位)或 256K(64 位架构).

So, by default, the stack size should be 192K (32bits) or 256K (64bits architectures).

首先检查mysqld二进制文件是如何编译的，看看默认值是多少:

First, check how the mysqld binary was compiled, to see what is the default value:

malff@linux-8edv:sql> pwd
/home/malff/BZR_TREE/mysql-5.1/sql
malff@linux-8edv:sql> ./mysqld --no-defaults --verbose --help | grep thread_stack
...
  --thread_stack=#    The stack size for each thread.
thread_stack                      262144

在我的系统上，我在 64 位平台上获得了 256K.

On my system, I got 256K on a 64 bits platform.

如果有不同的值，也许有人用不同的编译选项构建服务器，例如 -DDEFAULT_THREAD_STACK(或只是修改了源代码)......我会质疑在这种情况下二进制文件的来源.

If there are different values, maybe someone build the server with different compiling options, such as -DDEFAULT_THREAD_STACK (or just modified the source) ... I would question where the binary is coming from in that case.

其次，检查 my.cnf 以获取配置文件本身中提供的默认值.将值显式设置为 thread_stack 的行(并且具有较低的值)肯定会导致所看到的错误.

Second, check my.cnf for default values provided in the configuration file itself. A line setting a value to thread_stack explicitly (and with a low value) would definitively cause the error seen.

最后，检查服务器日志文件是否有这样的错误(参见 sql/mysqld.cc):

Last, check the server log file for an error such as this (see sql/mysqld.cc) :

sql_print_warning("Asked for %lu thread stack, but got %ld",
                  my_thread_stack_size, (long) stack_size);

服务器代码调用:

  • pthread_attr_setstacksize() 设置栈大小
  • pthread_attr_getstacksize() 来验证一个线程到底有多少堆栈并在日志中抱怨 pthread 库使用较少.

长话短说，看到错误是因为与服务器附带的默认值相比，thread_stack 太小了.这可能发生:

Long story short, the error is seen because the thread_stack is too small compared to the default values shipped with the server. This can happen:

  • 在进行服务器的自定义构建时，使用不同的编译选项
  • 更改 my.cnf 文件中的默认值时
  • 如果 pthread 库本身出现问题(理论上来自阅读代码，我自己从未见过).

我希望这能回答问题.

问候，——马克·阿尔夫

Regards, -- Marc Alff

更新 (2014-03-11)，使如何修复"更明显.

Update (2014-03-11), to make the "how to fix" more obvious.

发生的事情很可能是 my.cnf 文件中 thread_stack 文件的默认值发生了变化.

What is going on, in all likelihood, is that the default value for thread_stack file was changed in the my.cnf file.

然后如何修复它是微不足道的，找到在 my.cnf 文件中设置 thread_stack 的位置，然后删除设置(信任服务器代码提供合适的默认值，因此下次不会再发生这种情况)或增加堆栈大小.

How to fix it is trivial then, find where thread_stack is set in the my.cnf file, and either remove the setting (trusting the server code to provide a decent default value, so this does not happen again next time) or increase the stack size.

更新(2021-04-28)，查看thread_stack来自哪里:

Update (2021-04-28), check where the thread_stack comes from:

使用表 performance_schema.variables_info 找出给定变量的来源.

Use table performance_schema.variables_info to find out where a given variable comes from.

mysql> select * from variables_info where VARIABLE_NAME = 'thread_stack';
+---------------+-----------------+---------------+-----------+----------------------+----------+----------+----------+
| VARIABLE_NAME | VARIABLE_SOURCE | VARIABLE_PATH | MIN_VALUE | MAX_VALUE            | SET_TIME | SET_USER | SET_HOST |
+---------------+-----------------+---------------+-----------+----------------------+----------+----------+----------+
| thread_stack  | COMPILED        |               | 131072    | 18446744073709550592 | NULL     | NULL     | NULL     |
+---------------+-----------------+---------------+-----------+----------------------+----------+----------+----------+
1 row in set (0.01 sec)

这里默认是出厂值(在mysqld二进制文件中编译).

Here the default is the factory value (compiled in the mysqld binary).

另一个例子:

mysql> select * from variables_info where VARIABLE_NAME = 'thread_stack';
+---------------+-----------------+----------------------------------------------------------------+-----------+----------------------+----------+----------+----------+
| VARIABLE_NAME | VARIABLE_SOURCE | VARIABLE_PATH                                                  | MIN_VALUE | MAX_VALUE            | SET_TIME | SET_USER | SET_HOST |
+---------------+-----------------+----------------------------------------------------------------+-----------+----------------------+----------+----------+----------+
| thread_stack  | EXPLICIT        | /home/malff/CODE/GIT/GIT_TRUNK/build-dbg/mysql-test/var/my.cnf | 131072    | 18446744073709550592 | NULL     | NULL     | NULL     |
+---------------+-----------------+----------------------------------------------------------------+-----------+----------------------+----------+----------+----------+
1 row in set (0.00 sec)

这里的thread_stack是在上报的my.cnf文件中设置的.

Here the thread_stack is set in the my.cnf file reported.

雷夫曼:

https://dev.mysql.com/doc/refman/8.0/en/performance-schema-variables-info-table.html

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