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Merge 10.3 into 10.4

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This commit is contained in:
Marko Mäkelä
2020-05-13 12:52:57 +03:00
parent 9f20968169 15fa70b840
commit 38f6c47f8a
44 changed files with 208 additions and 305 deletions
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18
sql/sql_class.cc
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@ -4854,6 +4854,7 @@ extern "C" LEX_STRING * thd_query_string (MYSQL_THD thd)
@param buflen Length of the buffer
@return Length of the query
@retval 0 if LOCK_thd_data cannot be acquired without waiting
@note This function is thread safe as the query string is
accessed under mutex protection and the string is copied
@ -4862,10 +4863,19 @@ extern "C" LEX_STRING * thd_query_string (MYSQL_THD thd)
extern "C" size_t thd_query_safe(MYSQL_THD thd, char *buf, size_t buflen)
{
mysql_mutex_lock(&thd->LOCK_thd_data);
size_t len= MY_MIN(buflen - 1, thd->query_length());
memcpy(buf, thd->query(), len);
mysql_mutex_unlock(&thd->LOCK_thd_data);
size_t len= 0;
/* InnoDB invokes this function while holding internal mutexes.
THD::awake() will hold LOCK_thd_data while invoking an InnoDB
function that would acquire the internal mutex. Because this
function is a non-essential part of information_schema view output,
we will break the deadlock by avoiding a mutex wait here
and returning the empty string if a wait would be needed. */
if (!mysql_mutex_trylock(&thd->LOCK_thd_data))
{
len= MY_MIN(buflen - 1, thd->query_length());
memcpy(buf, thd->query(), len);
mysql_mutex_unlock(&thd->LOCK_thd_data);
}
buf[len]= '\0';
return len;
}