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Fixed wrong assignment in calculate_block_sizes() for MEM_ROOT

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The effect was that that ROOT_FLAG_THREAD_SPECIFIC was cleared and
the memory allocated by memroot would be contributed the the system,
not to the thread.

This exposed a bug in how "show explain for ..." allocated data.
- The thread that did provide the explain allocated data in the
  "show explain" threads mem_root, which is marked as THREAD_SPECIFIC.
- Fixed by allocating the explain data in a temporary explain_mem_root
  which is not THREAD_SPECIFIC.

Other things:
- Added extra checks when using update_malloc_size()
- Do not call update_malloc_size() for memory not registered with
  update_malloc_size(). This avoid some wrong 'memory not freed' reports.
- Added a checking of 'thd->killed' to ensure that
  main.truncate_notembedded.test still works.

Reported by: Yury Chaikou
This commit is contained in:
Monty
2023-06-12 20:11:32 +03:00
parent c4cf5e17ac
commit e1a631fecc
5 changed files with 54 additions and 18 deletions
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25
sql/sql_show.cc
View File

@@ -2988,7 +2988,7 @@ void Show_explain_request::call_in_target_thread()
target_thd->set_n_backup_active_arena((Query_arena*)request_thd,
&backup_arena);
query_str.copy(target_thd->query(),
query_str.copy(target_thd->query(),
target_thd->query_length(),
target_thd->query_charset());
@@ -3139,6 +3139,8 @@ int fill_show_explain_or_analyze(THD *thd, TABLE_LIST *table, COND *cond,
if ((tmp= find_thread_by_id(thread_id)))
{
Security_context *tmp_sctx= tmp->security_ctx;
MEM_ROOT explain_mem_root, *save_mem_root;
/*
If calling_user==NULL, calling thread has SUPER or PROCESS
privilege, and so can do SHOW EXPLAIN/SHOW ANALYZE on any user.
@@ -3164,7 +3166,8 @@ int fill_show_explain_or_analyze(THD *thd, TABLE_LIST *table, COND *cond,
bool bres;
/*
Ok we've found the thread of interest and it won't go away because
we're holding its LOCK_thd_kill. Post it a SHOW EXPLAIN/SHOW ANALYZE request.
we're holding its LOCK_thd_kill. Post it a SHOW EXPLAIN/SHOW ANALYZE
request.
*/
bool timed_out;
int timeout_sec= 30;
@@ -3172,7 +3175,9 @@ int fill_show_explain_or_analyze(THD *thd, TABLE_LIST *table, COND *cond,
explain_req.is_json_format= json_format;
select_result_explain_buffer *explain_buf;
explain_buf= new select_result_explain_buffer(thd, table->table);
if (!(explain_buf= new (thd->mem_root)
select_result_explain_buffer(thd, table->table)))
DBUG_RETURN(1);
explain_req.is_analyze= is_analyze;
explain_req.explain_buf= explain_buf;
@@ -3180,8 +3185,19 @@ int fill_show_explain_or_analyze(THD *thd, TABLE_LIST *table, COND *cond,
explain_req.request_thd= thd;
explain_req.failed_to_produce= FALSE;
/*
Do not use default memroot as this is only to be used by the
target thread (It's marked as thread MY_THREAD_SPECIFIC).
*/
init_sql_alloc(key_memory_thd_main_mem_root,
&explain_mem_root, 0, 8000, MYF(0));
save_mem_root= thd->mem_root;
thd->mem_root= &explain_mem_root;
/* Ok, we have a lock on target->LOCK_thd_kill, can call: */
bres= tmp->apc_target.make_apc_call(thd, &explain_req, timeout_sec, &timed_out);
bres= tmp->apc_target.make_apc_call(thd, &explain_req, timeout_sec,
&timed_out);
thd->mem_root= save_mem_root;
if (bres || explain_req.failed_to_produce)
{
@@ -3226,6 +3242,7 @@ int fill_show_explain_or_analyze(THD *thd, TABLE_LIST *table, COND *cond,
push_warning(thd, Sql_condition::WARN_LEVEL_NOTE,
ER_YES, warning_text);
}
free_root(&explain_mem_root, MYF(0));
DBUG_RETURN(bres);
}
my_error(ER_NO_SUCH_THREAD, MYF(0), (ulong) thread_id);