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Implement WL#2661 "Prepared Statements: Dynamic SQL in Stored Procedures".

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The idea of the patch is to separate statement processing logic,
such as parsing, validation of the parsed tree, execution and cleanup, 
from global query processing logic, such as logging, resetting
priorities of a thread, resetting stored procedure cache, resetting
thread count of errors and warnings.
This makes PREPARE and EXECUTE behave similarly to the rest of SQL
statements and allows their use in stored procedures.
This patch contains a change in behaviour:
until recently for each SQL prepared statement command, 2 queries
were written to the general log, e.g.
[Query]   prepare stmt from @stmt_text;
[Prepare] select * from t1 <-- contents of @stmt_text
The chagne was necessary to prevent [Prepare] commands from being written
to the general log when executing a stored procedure with Dynamic SQL.
We should consider whether the old behavior is preferrable and probably
restore it.
This patch refixes Bug#7115, Bug#10975 (partially), Bug#10605 (various bugs
in Dynamic SQL reported before it was disabled).


mysql-test/r/not_embedded_server.result:
  Since we don't want to log Dynamic SQL in stored procedures,
  now the general log gets only one log entry per SQL statement.
mysql-test/r/sp-error.result:
  - remove obsolete tests
  - a better error message for the case when a stored procedure that
  returns a result set is called from a function
mysql-test/r/trigger.result:
  - a better error message for the case when a stored procedure that
  returns a result set is called from a trigger
mysql-test/t/sp-error.test:
  - a better error message for the case when a stored procedure that
    returns a result set is called from a function.
  - move the comment to its place (end of file).
mysql-test/t/trigger.test:
  - a better error message for the case when a stored procedure that
  returns a result set is called from a trigger
sql/item_func.cc:
  - we need to pass sql_command explicitly to get_var_with_binlog, because
  when creating a query for SQL prepared statement thd->lex->sql_command
  points at SQLCOM_EXECUTE, which is not listed in the list of update
  queries.
sql/log_event.h:
  - remove an extra copy of the previous sentence
sql/mysql_priv.h:
  - fix declarations of sql_prepare.cc API
sql/share/errmsg.txt:
  - a new error message, when one attempts to execute a prepared statement
  which is currently being executed (this can happen only in Dynamic SQL
  at the moment).
sql/sp_head.cc:
  - extend sp_multi_results_command to return different flags for a
  command (and rename it)
  - add support for SQLCOM_PREPARE,SQLCOM_EXECUTE, SQLCOM_DEALLOCATE
    to sp_get_flags_for_command
  - replace multiple boolean sp_head members with uint m_flags
  - a fix for a crash when user variables are used in a stored procedure
    and binlog is on. A temporary fix for Bug#12637 "SP crashes the server 
   if it has update query with user var & binlog is enabled", which actually
   stands for stored functions: now instead of a crash we break
   replication if a user variable is used in a stored function which 
   is executed in prelocked mode.
sql/sp_head.h:
  - replace multiple boolean flags of sp_head with uint m_flags;
  - add flag CONTAINS_DYNAMIC_SQL
  - use this flag to error if a stored procedure with Dynamic SQL is
    called from a function or trigger.
sql/sql_class.cc:
  - Statement_map::insert should not delete a statement if it exists,
    now it's done externally to be able to handle the case when the
    statement being deleted is in use.
  - remove extra code (free_list is already reset in free_items)
sql/sql_lex.cc:
  - add lex->stmt_prepare_mode; we can't rely on thd->command any more,
    because we don't reset it any more (Dynamic SQL requirement is that
    PS are as little intrusive as possible).
sql/sql_lex.h:
  - declare bool LEX::stmt_prepare_mode
sql/sql_parse.cc:
  - move prepared statement code to sql_prepare.cc
  - change declarations (refactored code)
  - better error message when one attempts to use Dynamic SQL or a 
    stored procedure that returns a result set in a function or trigger.
sql/sql_prepare.cc:
  - major refactoring to ensure PREPARE/EXECUTE commands do not reset global THD
    state and allow their use in stored procedures.
  - add Prepared_statement::flags and use it to ensure no recursive execution
    of a prepared statement is possible
  - better comments
sql/sql_yacc.yy:
  - enable PREPARE/EXECUTE/DEALLOCATE in stored procedures
  - produce an error message on attempt to use PREPARE/EXECUTE/DEALLOCATE
    in a stored function or trigger
mysql-test/r/sp-dynamic.result:
  - sp-dynamic.test results
mysql-test/t/sp-dynamic.test:
  - a new test for PREPARE/EXECUTE/DEALLOCATE in stored procedures.
This commit is contained in:
unknown
2005-09-03 03:13:18 +04:00
parent dc92221300
commit c910050a76
19 changed files with 1679 additions and 700 deletions
Download Patch File Download Diff File Expand all files Collapse all files

135
sql/sql_parse.cc
View File

@@ -1644,7 +1644,7 @@ bool dispatch_command(enum enum_server_command command, THD *thd,
}
case COM_STMT_PREPARE:
{
mysql_stmt_prepare(thd, packet, packet_length, 0);
mysql_stmt_prepare(thd, packet, packet_length);
break;
}
case COM_STMT_CLOSE:
@@ -1664,6 +1664,10 @@ bool dispatch_command(enum enum_server_command command, THD *thd,
char *packet_end= thd->query + thd->query_length;
mysql_log.write(thd,command,"%s",thd->query);
DBUG_PRINT("query",("%-.4096s",thd->query));
if (!(specialflag & SPECIAL_NO_PRIOR))
my_pthread_setprio(pthread_self(),QUERY_PRIOR);
mysql_parse(thd,thd->query, thd->query_length);
while (!thd->killed && thd->lex->found_semicolon && !thd->net.report_error)
@@ -2220,7 +2224,7 @@ int prepare_schema_table(THD *thd, LEX *lex, Table_ident *table_ident,
TRUE error; In this case thd->fatal_error is set
*/
bool alloc_query(THD *thd, char *packet, ulong packet_length)
bool alloc_query(THD *thd, const char *packet, uint packet_length)
{
packet_length--; // Remove end null
/* Remove garbage at start and end of query */
@@ -2229,7 +2233,7 @@ bool alloc_query(THD *thd, char *packet, ulong packet_length)
packet++;
packet_length--;
}
char *pos=packet+packet_length; // Point at end null
const char *pos= packet + packet_length; // Point at end null
while (packet_length > 0 &&
(pos[-1] == ';' || my_isspace(thd->charset() ,pos[-1])))
{
@@ -2250,8 +2254,6 @@ bool alloc_query(THD *thd, char *packet, ulong packet_length)
thd->packet.shrink(thd->variables.net_buffer_length);
thd->convert_buffer.shrink(thd->variables.net_buffer_length);
if (!(specialflag & SPECIAL_NO_PRIOR))
my_pthread_setprio(pthread_self(),QUERY_PRIOR);
return FALSE;
}
@@ -2466,112 +2468,17 @@ mysql_execute_command(THD *thd)
}
case SQLCOM_PREPARE:
{
char *query_str;
uint query_len;
if (lex->prepared_stmt_code_is_varref)
{
/* This is PREPARE stmt FROM @var. */
String str;
CHARSET_INFO *to_cs= thd->variables.collation_connection;
bool need_conversion;
user_var_entry *entry;
String *pstr= &str;
uint32 unused;
/*
Convert @var contents to string in connection character set. Although
it is known that int/real/NULL value cannot be a valid query we still
convert it for error messages to uniform.
*/
if ((entry=
(user_var_entry*)hash_search(&thd->user_vars,
(byte*)lex->prepared_stmt_code.str,
lex->prepared_stmt_code.length))
&& entry->value)
{
my_bool is_var_null;
pstr= entry->val_str(&is_var_null, &str, NOT_FIXED_DEC);
/*
NULL value of variable checked early as entry->value so here
we can't get NULL in normal conditions
*/
DBUG_ASSERT(!is_var_null);
if (!pstr)
goto error;
}
else
{
/*
variable absent or equal to NULL, so we need to set variable to
something reasonable to get readable error message during parsing
*/
str.set("NULL", 4, &my_charset_latin1);
}
need_conversion=
String::needs_conversion(pstr->length(), pstr->charset(),
to_cs, &unused);
query_len= need_conversion? (pstr->length() * to_cs->mbmaxlen) :
pstr->length();
if (!(query_str= alloc_root(thd->mem_root, query_len+1)))
goto error;
if (need_conversion)
{
uint dummy_errors;
query_len= copy_and_convert(query_str, query_len, to_cs,
pstr->ptr(), pstr->length(),
pstr->charset(), &dummy_errors);
}
else
memcpy(query_str, pstr->ptr(), pstr->length());
query_str[query_len]= 0;
}
else
{
query_str= lex->prepared_stmt_code.str;
query_len= lex->prepared_stmt_code.length;
DBUG_PRINT("info", ("PREPARE: %.*s FROM '%.*s' \n",
lex->prepared_stmt_name.length,
lex->prepared_stmt_name.str,
query_len, query_str));
}
thd->command= COM_STMT_PREPARE;
if (!(res= mysql_stmt_prepare(thd, query_str, query_len + 1,
&lex->prepared_stmt_name)))
send_ok(thd, 0L, 0L, "Statement prepared");
mysql_sql_stmt_prepare(thd);
break;
}
case SQLCOM_EXECUTE:
{
DBUG_PRINT("info", ("EXECUTE: %.*s\n",
lex->prepared_stmt_name.length,
lex->prepared_stmt_name.str));
mysql_sql_stmt_execute(thd, &lex->prepared_stmt_name);
lex->prepared_stmt_params.empty();
mysql_sql_stmt_execute(thd);
break;
}
case SQLCOM_DEALLOCATE_PREPARE:
{
Statement* stmt;
DBUG_PRINT("info", ("DEALLOCATE PREPARE: %.*s\n",
lex->prepared_stmt_name.length,
lex->prepared_stmt_name.str));
/* We account deallocate in the same manner as mysql_stmt_close */
statistic_increment(thd->status_var.com_stmt_close, &LOCK_status);
if ((stmt= thd->stmt_map.find_by_name(&lex->prepared_stmt_name)))
{
thd->stmt_map.erase(stmt);
send_ok(thd);
}
else
{
my_error(ER_UNKNOWN_STMT_HANDLER, MYF(0),
lex->prepared_stmt_name.length,
lex->prepared_stmt_name.str,
"DEALLOCATE PREPARE");
goto error;
}
mysql_sql_stmt_close(thd);
break;
}
case SQLCOM_DO:
@@ -4124,7 +4031,7 @@ end_with_restore_list:
}
#endif
if (lex->sphead->m_type == TYPE_ENUM_FUNCTION &&
!lex->sphead->m_has_return)
!(lex->sphead->m_flags & sp_head::HAS_RETURN))
{
my_error(ER_SP_NORETURN, MYF(0), name);
delete lex->sphead;
@@ -4213,15 +4120,31 @@ end_with_restore_list:
ha_rows select_limit;
/* bits that should be cleared in thd->server_status */
uint bits_to_be_cleared= 0;
/*
Check that the stored procedure doesn't contain Dynamic SQL
and doesn't return result sets: such stored procedures can't
be called from a function or trigger.
*/
if (thd->in_sub_stmt)
{
const char *where= (thd->in_sub_stmt & SUB_STMT_TRIGGER ?
"trigger" : "function");
if (sp->is_not_allowed_in_function(where))
goto error;
}
#ifndef EMBEDDED_LIBRARY
my_bool nsok= thd->net.no_send_ok;
thd->net.no_send_ok= TRUE;
#endif
if (sp->m_multi_results)
if (sp->m_flags & sp_head::MULTI_RESULTS)
{
if (! (thd->client_capabilities & CLIENT_MULTI_RESULTS))
{
/*
The client does not support multiple result sets being sent
back
*/
my_error(ER_SP_BADSELECT, MYF(0), sp->m_qname.str);
#ifndef EMBEDDED_LIBRARY
thd->net.no_send_ok= nsok;
@@ -4265,7 +4188,7 @@ end_with_restore_list:
thd->row_count_func= 0;
/*
We never write CALL statements int binlog:
We never write CALL statements into binlog:
- If the mode is non-prelocked, each statement will be logged
separately.
- If the mode is prelocked, the invoking statement will care