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MWL#182: Explain running statements: address review feedback

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- switch SHOW EXPLAIN to using an INFORMATION_SCHEMA table.
This commit is contained in:
Sergey Petrunya
2012-07-10 21:23:00 +04:00
parent a931467e17
commit 725d76e1e8
11 changed files with 118 additions and 175 deletions
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66
sql/sql_show.cc
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@ -1999,32 +1999,24 @@ void mysqld_list_processes(THD *thd,const char *user, bool verbose)
}
static
const char *target_not_explainable_cmd="Target is not running EXPLAINable command";
/*
SHOW EXPLAIN FOR command handler
@param thd Current thread's thd
@param calling_user User that invoked SHOW EXPLAIN, or NULL if the user
has SUPER or PROCESS privileges, and so is allowed
to run SHOW EXPLAIN on anybody.
@param thread_id Thread whose explain we need
@notes
- Attempt to do "SHOW EXPLAIN FOR <myself>" will properly produce "target not
running EXPLAINable command".
Store the SHOW EXPLAIN output in the temporary table.
*/
void mysqld_show_explain(THD *thd, const char *calling_user, ulong thread_id)
int fill_show_explain(THD *thd, TABLE_LIST *table, COND *cond)
{
const char *calling_user;
THD *tmp;
Protocol *protocol= thd->protocol;
List<Item> field_list;
DBUG_ENTER("mysqld_show_explain");
thd->make_explain_field_list(field_list);
if (protocol->send_result_set_metadata(&field_list, Protocol::SEND_NUM_ROWS |
Protocol::SEND_EOF))
DBUG_VOID_RETURN;
my_thread_id thread_id;
DBUG_ENTER("fill_show_explain");
DBUG_ASSERT(cond==NULL);
thread_id= thd->lex->show_explain_for_thread->val_int();
calling_user= (thd->security_ctx->master_access & PROCESS_ACL) ? NullS :
thd->security_ctx->priv_user;
/*
Find the thread we need EXPLAIN for. Thread search code was copied from
kill_one_thread()
@ -2042,7 +2034,7 @@ void mysqld_show_explain(THD *thd, const char *calling_user, ulong thread_id)
}
}
mysql_mutex_unlock(&LOCK_thread_count);
if (tmp)
{
Security_context *tmp_sctx= tmp->security_ctx;
@ -2058,7 +2050,15 @@ void mysqld_show_explain(THD *thd, const char *calling_user, ulong thread_id)
{
my_error(ER_SPECIFIC_ACCESS_DENIED_ERROR, MYF(0), "PROCESSLIST");
mysql_mutex_unlock(&tmp->LOCK_thd_data);
DBUG_VOID_RETURN;
DBUG_RETURN(1);
}
if (tmp == thd)
{
mysql_mutex_unlock(&tmp->LOCK_thd_data);
my_error(ER_ERROR_WHEN_EXECUTING_COMMAND, MYF(0), "SHOW EXPLAIN",
target_not_explainable_cmd);
DBUG_RETURN(1);
}
bool bres;
@ -2071,9 +2071,7 @@ void mysqld_show_explain(THD *thd, const char *calling_user, ulong thread_id)
Show_explain_request explain_req;
select_result_explain_buffer *explain_buf;
explain_buf= new select_result_explain_buffer;
explain_buf->thd=thd;
explain_buf->protocol= thd->protocol;
explain_buf= new select_result_explain_buffer(thd, table->table);
explain_req.explain_buf= explain_buf;
explain_req.target_thd= tmp;
@ -2099,29 +2097,22 @@ void mysqld_show_explain(THD *thd, const char *calling_user, ulong thread_id)
else
{
my_error(ER_ERROR_WHEN_EXECUTING_COMMAND, MYF(0),
"SHOW EXPLAIN",
"Target is not running EXPLAINable command");
"SHOW EXPLAIN", target_not_explainable_cmd);
}
bres= TRUE;
explain_buf->discard_data();
}
else
{
push_warning(thd, MYSQL_ERROR::WARN_LEVEL_NOTE,
ER_YES, explain_req.query_str.c_ptr_safe());
}
if (!bres)
{
explain_buf->flush_data();
my_eof(thd);
}
DBUG_RETURN(bres);
}
else
{
my_error(ER_NO_SUCH_THREAD, MYF(0), thread_id);
DBUG_RETURN(1);
}
DBUG_VOID_RETURN;
}
@ -8436,6 +8427,7 @@ ST_FIELD_INFO keycache_fields_info[]=
};
extern ST_FIELD_INFO show_explain_fields_info[];
/*
Description of ST_FIELD_INFO in table.h
@ -8467,6 +8459,8 @@ ST_SCHEMA_TABLE schema_tables[]=
{"EVENTS", events_fields_info, create_schema_table,
0, make_old_format, 0, -1, -1, 0, 0},
#endif
{"EXPLAIN", show_explain_fields_info, create_schema_table, fill_show_explain,
make_old_format, 0, -1, -1, TRUE /*hidden*/ , 0},
{"FILES", files_fields_info, create_schema_table,
hton_fill_schema_table, 0, 0, -1, -1, 0, 0},
{"GLOBAL_STATUS", variables_fields_info, create_schema_table,