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Port of cursors to be pushed into 5.0 tree:

Browse Source 
- client side part is simple and may be considered stable
- server side part now just joggles with THD state to save execution
  state and has no additional locking wisdom.
  Lot's of it are to be rewritten.
This commit is contained in:
konstantin@mysql.com
2004-08-03 03:32:21 -07:00
parent 7e6bade23b
commit d3e520ce7e
31 changed files with 1091 additions and 150 deletions
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154
sql/sql_prepare.cc
View File

@@ -75,6 +75,8 @@ Long data handling:
#ifdef EMBEDDED_LIBRARY
/* include MYSQL_BIND headers */
#include <mysql.h>
#else
#include <mysql_com.h>
#endif
/******************************************************************************
@@ -107,7 +109,7 @@ public:
};
static void execute_stmt(THD *thd, Prepared_statement *stmt,
String *expanded_query, bool set_context);
String *expanded_query);
/******************************************************************************
Implementation
@@ -166,7 +168,8 @@ static bool send_prep_stmt(Prepared_statement *stmt, uint columns)
return my_net_write(net, buff, sizeof(buff)) ||
(stmt->param_count &&
stmt->thd->protocol_simple.send_fields((List<Item> *)
&stmt->lex->param_list, 0)) ||
&stmt->lex->param_list,
Protocol::SEND_EOF)) ||
net_flush(net);
return 0;
}
@@ -1098,7 +1101,8 @@ static int mysql_test_select(Prepared_statement *stmt,
if (!text_protocol)
{
if (send_prep_stmt(stmt, lex->select_lex.item_list.elements) ||
thd->protocol_simple.send_fields(&lex->select_lex.item_list, 0)
thd->protocol_simple.send_fields(&lex->select_lex.item_list,
Protocol::SEND_EOF)
#ifndef EMBEDDED_LIBRARY
|| net_flush(&thd->net)
#endif
@@ -1476,6 +1480,12 @@ static int send_prepare_results(Prepared_statement *stmt, bool text_protocol)
case SQLCOM_SHOW_GRANTS:
case SQLCOM_DROP_TABLE:
case SQLCOM_RENAME_TABLE:
case SQLCOM_ALTER_TABLE:
case SQLCOM_COMMIT:
case SQLCOM_CREATE_INDEX:
case SQLCOM_DROP_INDEX:
case SQLCOM_ROLLBACK:
case SQLCOM_TRUNCATE:
break;
default:
@@ -1756,6 +1766,7 @@ static void reset_stmt_params(Prepared_statement *stmt)
void mysql_stmt_execute(THD *thd, char *packet, uint packet_length)
{
ulong stmt_id= uint4korr(packet);
ulong flags= (ulong) ((uchar) packet[4]);
/*
Query text for binary log, or empty string if the query is not put into
binary log.
@@ -1782,6 +1793,28 @@ void mysql_stmt_execute(THD *thd, char *packet, uint packet_length)
DBUG_VOID_RETURN;
}
if (flags & (ulong) CURSOR_TYPE_READ_ONLY)
{
if (stmt->lex->result)
{
/*
If lex->result is set in the parser, this is not a SELECT
statement: we can't open a cursor for it.
*/
flags= 0;
}
else
{
if (!stmt->cursor &&
!(stmt->cursor= new (&stmt->mem_root) Cursor()))
{
send_error(thd, ER_OUT_OF_RESOURCES);
DBUG_VOID_RETURN;
}
/* If lex->result is set, mysql_execute_command will use it */
stmt->lex->result= &stmt->cursor->result;
}
}
#ifndef EMBEDDED_LIBRARY
if (stmt->param_count)
{
@@ -1800,16 +1833,55 @@ void mysql_stmt_execute(THD *thd, char *packet, uint packet_length)
if (stmt->param_count && stmt->set_params_data(stmt, &expanded_query))
goto set_params_data_err;
#endif
thd->stmt_backup.set_statement(thd);
thd->set_statement(stmt);
thd->current_arena= stmt;
reset_stmt_for_execute(thd, stmt->lex);
/* From now cursors assume that thd->mem_root is clean */
if (expanded_query.length() &&
alloc_query(thd, (char *)expanded_query.ptr(),
expanded_query.length()+1))
{
my_error(ER_OUTOFMEMORY, 0, expanded_query.length());
goto err;
}
thd->protocol= &thd->protocol_prep; // Switch to binary protocol
execute_stmt(thd, stmt, &expanded_query, true);
if (!(specialflag & SPECIAL_NO_PRIOR))
my_pthread_setprio(pthread_self(),QUERY_PRIOR);
mysql_execute_command(thd);
if (!(specialflag & SPECIAL_NO_PRIOR))
my_pthread_setprio(pthread_self(), WAIT_PRIOR);
thd->protocol= &thd->protocol_simple; // Use normal protocol
if (flags & (ulong) CURSOR_TYPE_READ_ONLY)
{
if (stmt->cursor->is_open())
stmt->cursor->init_from_thd(thd);
thd->set_item_arena(&thd->stmt_backup);
}
else
{
thd->lex->unit.cleanup();
cleanup_items(stmt->free_list);
reset_stmt_params(stmt);
close_thread_tables(thd); /* to close derived tables */
/*
Free items that were created during this execution of the PS by
query optimizer.
*/
free_items(thd->free_list);
thd->free_list= 0;
}
thd->set_statement(&thd->stmt_backup);
thd->current_arena= 0;
DBUG_VOID_RETURN;
set_params_data_err:
reset_stmt_params(stmt);
my_error(ER_WRONG_ARGUMENTS, MYF(0), "mysql_stmt_execute");
err:
send_error(thd);
DBUG_VOID_RETURN;
}
@@ -1845,7 +1917,6 @@ void mysql_sql_stmt_execute(THD *thd, LEX_STRING *stmt_name)
DBUG_VOID_RETURN;
}
thd->free_list= NULL;
thd->stmt_backup.set_statement(thd);
thd->set_statement(stmt);
if (stmt->set_params_from_vars(stmt,
@@ -1856,7 +1927,7 @@ void mysql_sql_stmt_execute(THD *thd, LEX_STRING *stmt_name)
send_error(thd);
}
thd->current_arena= stmt;
execute_stmt(thd, stmt, &expanded_query, false);
execute_stmt(thd, stmt, &expanded_query);
thd->current_arena= 0;
DBUG_VOID_RETURN;
}
@@ -1872,20 +1943,13 @@ void mysql_sql_stmt_execute(THD *thd, LEX_STRING *stmt_name)
placeholders replaced with actual values. Otherwise empty
string.
NOTES
Caller must set parameter values and thd::protocol.
thd->free_list is assumed to be garbage.
Caller must set parameter values and thd::protocol.
*/
static void execute_stmt(THD *thd, Prepared_statement *stmt,
String *expanded_query, bool set_context)
String *expanded_query)
{
DBUG_ENTER("execute_stmt");
if (set_context)
{
thd->free_list= NULL;
thd->stmt_backup.set_statement(thd);
thd->set_statement(stmt);
}
reset_stmt_for_execute(thd, stmt->lex);
if (expanded_query->length() &&
@@ -1899,21 +1963,76 @@ static void execute_stmt(THD *thd, Prepared_statement *stmt,
if (!(specialflag & SPECIAL_NO_PRIOR))
my_pthread_setprio(pthread_self(),QUERY_PRIOR);
mysql_execute_command(thd);
thd->lex->unit.cleanup();
if (!(specialflag & SPECIAL_NO_PRIOR))
my_pthread_setprio(pthread_self(), WAIT_PRIOR);
thd->lex->unit.cleanup();
cleanup_items(stmt->free_list);
reset_stmt_params(stmt);
close_thread_tables(thd); // to close derived tables
thd->set_statement(&thd->stmt_backup);
/* Free Items that were created during this execution of the PS. */
free_items(thd->free_list);
/*
In the rest of prepared statements code we assume that free_list
never points to garbage: keep this predicate true.
*/
thd->free_list= 0;
DBUG_VOID_RETURN;
}
/*
COM_FETCH handler: fetches requested amount of rows from cursor
SYNOPSIS
*/
void mysql_stmt_fetch(THD *thd, char *packet, uint packet_length)
{
/* assume there is always place for 8-16 bytes */
ulong stmt_id= uint4korr(packet);
ulong num_rows= uint4korr(packet+=4);
Statement *stmt;
int error;
DBUG_ENTER("mysql_stmt_fetch");
if (!(stmt= thd->stmt_map.find(stmt_id)) ||
!stmt->cursor ||
!stmt->cursor->is_open())
{
my_error(ER_UNKNOWN_STMT_HANDLER, MYF(0), stmt_id, "fetch");
send_error(thd);
DBUG_VOID_RETURN;
}
thd->stmt_backup.set_statement(thd);
thd->stmt_backup.set_item_arena(thd);
thd->set_statement(stmt);
stmt->cursor->init_thd(thd);
if (!(specialflag & SPECIAL_NO_PRIOR))
my_pthread_setprio(pthread_self(), QUERY_PRIOR);
thd->protocol= &thd->protocol_prep; // Switch to binary protocol
error= stmt->cursor->fetch(num_rows);
thd->protocol= &thd->protocol_simple; // Use normal protocol
if (!(specialflag & SPECIAL_NO_PRIOR))
my_pthread_setprio(pthread_self(), WAIT_PRIOR);
/* Restore THD state */
stmt->cursor->reset_thd(thd);
thd->set_statement(&thd->stmt_backup);
thd->set_item_arena(&thd->stmt_backup);
if (error && error != -4)
send_error(thd, ER_OUT_OF_RESOURCES);
DBUG_VOID_RETURN;
}
/*
Reset a prepared statement in case there was a recoverable error.
SYNOPSIS
@@ -2084,8 +2203,11 @@ void Prepared_statement::setup_set_params()
}
}
Prepared_statement::~Prepared_statement()
{
if (cursor)
cursor->Cursor::~Cursor();
free_items(free_list);
}