From 3271588bb7c7e31ae9474c29b6c370fa3876e7b3 Mon Sep 17 00:00:00 2001
From: Thirunarayanan Balathandayuthapani <thiru@mariadb.com>
Date: Fri, 14 Jun 2024 12:46:02 +0530
Subject: [PATCH 1/4] MDEV-34381 During innodb_undo_truncate=ON recovery,
InnoDB may fail to shrink undo* files
- During recovery, InnoDB may fail to shrink the undo tablespaces
when there are no pages to recover while applying the redo log.
This issue exists only when innodb_undo_truncate is enabled.
trx_lists_init_at_db_start() could've applied the redo logs
for undo tablespace page0.
---
storage/innobase/log/log0recv.cc | 47 ++++++++++++++++----------------
1 file changed, 23 insertions(+), 24 deletions(-)
diff --git a/storage/innobase/log/log0recv.cc b/storage/innobase/log/log0recv.cc
index 620e9c9209d..f83f5f45af6 100644
--- a/storage/innobase/log/log0recv.cc
+++ b/storage/innobase/log/log0recv.cc
@@ -2668,6 +2668,29 @@ void recv_sys_t::apply(bool last_batch)
recv_no_ibuf_operations = !last_batch ||
srv_operation == SRV_OPERATION_RESTORE ||
srv_operation == SRV_OPERATION_RESTORE_EXPORT;
+ for (auto id= srv_undo_tablespaces_open; id--;)
+ {
+ const trunc& t= truncated_undo_spaces[id];
+ if (t.lsn)
+ {
+ /* The entire undo tablespace will be reinitialized by
+ innodb_undo_log_truncate=ON. Discard old log for all pages.
+ Even though we recv_sys_t::parse() already invoked trim(),
+ this will be needed in case recovery consists of multiple batches
+ (there was an invocation with !last_batch). */
+ trim({id + srv_undo_space_id_start, 0}, t.lsn);
+ if (fil_space_t *space = fil_space_get(id + srv_undo_space_id_start))
+ {
+ ut_ad(UT_LIST_GET_LEN(space->chain) == 1);
+ ut_ad(space->recv_size >= t.pages);
+ fil_node_t *file= UT_LIST_GET_FIRST(space->chain);
+ ut_ad(file->is_open());
+ os_file_truncate(file->name, file->handle,
+ os_offset_t{space->recv_size} <<
+ srv_page_size_shift, true);
+ }
+ }
+ }
mtr_t mtr;
@@ -2683,30 +2706,6 @@ void recv_sys_t::apply(bool last_batch)
apply_log_recs= true;
apply_batch_on= true;
- for (auto id= srv_undo_tablespaces_open; id--;)
- {
- const trunc& t= truncated_undo_spaces[id];
- if (t.lsn)
- {
- /* The entire undo tablespace will be reinitialized by
- innodb_undo_log_truncate=ON. Discard old log for all pages.
- Even though we recv_sys_t::parse() already invoked trim(),
- this will be needed in case recovery consists of multiple batches
- (there was an invocation with !last_batch). */
- trim({id + srv_undo_space_id_start, 0}, t.lsn);
- if (fil_space_t *space = fil_space_get(id + srv_undo_space_id_start))
- {
- ut_ad(UT_LIST_GET_LEN(space->chain) == 1);
- ut_ad(space->recv_size >= t.pages);
- fil_node_t *file= UT_LIST_GET_FIRST(space->chain);
- ut_ad(file->is_open());
- os_file_truncate(file->name, file->handle,
- os_offset_t{space->recv_size} <<
- srv_page_size_shift, true);
- }
- }
- }
-
fil_system.extend_to_recv_size();
/* Release the log_sys mutex in non-last batches of multi-batch
From 4b4c371fe79ebf471450fed042bb1bcb94544a79 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Marko=20M=C3=A4kel=C3=A4?= <marko.makela@mariadb.com>
Date: Fri, 14 Jun 2024 13:21:19 +0300
Subject: [PATCH 2/4] MDEV-34297 fixup: -Wconversion on 32-bit
---
storage/innobase/include/ut0counter.h | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/storage/innobase/include/ut0counter.h b/storage/innobase/include/ut0counter.h
index 0083627b91f..b30c3df3f0d 100644
--- a/storage/innobase/include/ut0counter.h
+++ b/storage/innobase/include/ut0counter.h
@@ -56,7 +56,7 @@ struct ib_counter_t {
/** Add to the counter.
@param[in] n amount to be added */
- void add(Type n) { add(my_pseudo_random(), n); }
+ void add(Type n) { add(size_t(my_pseudo_random()), n); }
/** Add to the counter.
@param[in] index a reasonably thread-unique identifier
From fef32fd9ad844baa8b38b7f1a7da3b4ed2a772e5 Mon Sep 17 00:00:00 2001
From: Monty <monty@mariadb.org>
Date: Sat, 15 Jun 2024 14:26:07 +0300
Subject: [PATCH 3/4] MDEV-34406 Enhance mariadb_upgrade to print failing query
in case of error
To make this possible, it was also necessary to enhance the mariadb
client with the option --print-query-on-error.
This option can also be very useful when running a batch of queries
through the mariadb client and one wants to find out where things goes
wrong.
TODO: It would be good to enhance mariadb_upgrade to not call the mariadb
client for executing queries but instead do this internally. This
would have made this patch much easier!
Reviewed by: Sergei Golubchik <serg@mariadb.com>
---
client/mysql.cc | 66 +++++++++++++++++++++++++++-----
client/mysql_upgrade.c | 62 +++++++++++++++++++-----------
mysql-test/main/mysqldump.result | 6 ++-
3 files changed, 101 insertions(+), 33 deletions(-)
diff --git a/client/mysql.cc b/client/mysql.cc
index 1e235c8a34d..9591ffb096a 100644
--- a/client/mysql.cc
+++ b/client/mysql.cc
@@ -158,7 +158,8 @@ static my_bool ignore_errors=0,wait_flag=0,quick=0,
default_pager_set= 0, opt_sigint_ignore= 0,
auto_vertical_output= 0,
show_warnings= 0, executing_query= 0,
- ignore_spaces= 0, opt_binhex= 0, opt_progress_reports;
+ ignore_spaces= 0, opt_binhex= 0, opt_progress_reports,
+ opt_print_query_on_error;
static my_bool debug_info_flag, debug_check_flag, batch_abort_on_error;
static my_bool column_types_flag;
static my_bool preserve_comments= 0;
@@ -237,6 +238,7 @@ static int com_quit(String *str,char*),
com_prompt(String *str, char*), com_delimiter(String *str, char*),
com_warnings(String *str, char*), com_nowarnings(String *str, char*),
com_sandbox(String *str, char*);
+static void print_query_to_stderr(String *buffer);
#ifdef USE_POPEN
static int com_nopager(String *str, char*), com_pager(String *str, char*),
@@ -1659,6 +1661,10 @@ static struct my_option my_long_options[] =
#endif
"built-in default (" STRINGIFY_ARG(MYSQL_PORT) ").", &opt_mysql_port,
&opt_mysql_port, 0, GET_UINT, REQUIRED_ARG, 0, 0, 0, 0, 0, 0},
+ {"print-query-on-error", 0,
+ "Print the query if there was an error. Is only enabled in --batch mode if verbose is not set (as then the query would be printed anyway)",
+ &opt_print_query_on_error, &opt_print_query_on_error, 0, GET_BOOL, NO_ARG,
+ 1, 0, 0, 0, 0, 0},
{"progress-reports", 0,
"Get progress reports for long running commands (like ALTER TABLE)",
&opt_progress_reports, &opt_progress_reports, 0, GET_BOOL, NO_ARG, 1, 0,
@@ -3086,6 +3092,11 @@ int mysql_real_query_for_lazy(const char *buf, size_t length)
int error;
if (!mysql_real_query(&mysql,buf,(ulong)length))
return 0;
+ if (opt_print_query_on_error)
+ {
+ String query(buf, length, charset_info);
+ (void) print_query_to_stderr(&query);
+ }
error= put_error(&mysql);
if (mysql_errno(&mysql) != CR_SERVER_GONE_ERROR || retry > 1 ||
!opt_reconnect)
@@ -3291,7 +3302,6 @@ static int com_charset(String *, char *line)
1 if fatal error
*/
-
static int com_go(String *buffer, char *)
{
char buff[200]; /* about 110 chars used so far */
@@ -3363,6 +3373,8 @@ static int com_go(String *buffer, char *)
{
if (!(result=mysql_use_result(&mysql)) && mysql_field_count(&mysql))
{
+ if (opt_print_query_on_error)
+ print_query_to_stderr(buffer);
error= put_error(&mysql);
goto end;
}
@@ -3416,7 +3428,11 @@ static int com_go(String *buffer, char *)
(long) mysql_num_rows(result) == 1 ? "row" : "rows");
end_pager();
if (mysql_errno(&mysql))
+ {
+ if (opt_print_query_on_error)
+ print_query_to_stderr(buffer);
error= put_error(&mysql);
+ }
}
}
else if (mysql_affected_rows(&mysql) == ~(ulonglong) 0)
@@ -3443,13 +3459,21 @@ static int com_go(String *buffer, char *)
put_info("",INFO_RESULT); // Empty row
if (result && !mysql_eof(result)) /* Something wrong when using quick */
+ {
+ if (opt_print_query_on_error)
+ print_query_to_stderr(buffer);
error= put_error(&mysql);
+ }
else if (unbuffered)
fflush(stdout);
mysql_free_result(result);
} while (!(err= mysql_next_result(&mysql)));
if (err >= 1)
+ {
+ if (opt_print_query_on_error)
+ print_query_to_stderr(buffer);
error= put_error(&mysql);
+ }
end:
@@ -4375,14 +4399,35 @@ static int com_shell(String *, char *line)
#endif
+static void print_query(String *buffer, FILE *file)
+{
+ tee_puts("--------------", file);
+ (void) tee_fputs(buffer->c_ptr(), file);
+ if (!buffer->length() || (*buffer)[buffer->length()-1] != '\n')
+ tee_putc('\n', file);
+ tee_puts("--------------\n", file);
+}
+
+
+/*
+ Print query to stderr in batch mode if verbose is not set
+*/
+
+static void print_query_to_stderr(String *buffer)
+{
+ if ((status.batch || in_com_source) && !verbose)
+ {
+ fflush(stdout);
+ print_query(buffer, stderr);
+ fflush(stderr);
+ }
+}
+
+
static int com_print(String *buffer,char *)
{
- tee_puts("--------------", stdout);
- (void) tee_fputs(buffer->c_ptr(), stdout);
- if (!buffer->length() || (*buffer)[buffer->length()-1] != '\n')
- tee_putc('\n', stdout);
- tee_puts("--------------\n", stdout);
- return 0; /* If empty buffer */
+ print_query(buffer, stdout);
+ return 0;
}
@@ -5117,8 +5162,9 @@ put_info(const char *str,INFO_TYPE info_type, uint error, const char *sqlstate)
static int put_error(MYSQL *con)
{
- return put_info(mysql_error(con), INFO_ERROR, mysql_errno(con),
- mysql_sqlstate(con));
+ DBUG_ENTER("put_error");
+ DBUG_RETURN(put_info(mysql_error(con), INFO_ERROR,
+ mysql_errno(con), mysql_sqlstate(con)));
}
diff --git a/client/mysql_upgrade.c b/client/mysql_upgrade.c
index b303ffd099a..f81cff2797c 100644
--- a/client/mysql_upgrade.c
+++ b/client/mysql_upgrade.c
@@ -628,7 +628,7 @@ static int run_query(const char *query, DYNAMIC_STRING *ds_res,
{
my_close(fd, MYF(MY_WME));
my_delete(query_file_path, MYF(0));
- die("Failed to write to '%s'", query_file_path);
+ die("Failed to write query to '%s'", query_file_path);
}
}
@@ -637,7 +637,7 @@ static int run_query(const char *query, DYNAMIC_STRING *ds_res,
{
my_close(fd, MYF(MY_WME));
my_delete(query_file_path, MYF(0));
- die("Failed to write to '%s'", query_file_path);
+ die("Failed to write query to '%s'", query_file_path);
}
ret= run_tool(mysql_path,
@@ -647,6 +647,7 @@ static int run_query(const char *query, DYNAMIC_STRING *ds_res,
"--batch", /* Turns off pager etc. */
force ? "--force": "--skip-force",
opt_verbose >= 5 ? "--verbose" : "",
+ "--print-query-on-error",
ds_res || opt_silent ? "--silent": "",
"<",
query_file_path,
@@ -1085,18 +1086,6 @@ static char* get_line(char* line)
return line;
}
-
-/* Print the current line to stderr */
-static void print_line(char* line)
-{
- while (*line && *line != '\n')
- {
- fputc(*line, stderr);
- line++;
- }
- fputc('\n', stderr);
-}
-
static my_bool from_before_10_1()
{
my_bool ret= TRUE;
@@ -1308,16 +1297,21 @@ static int check_slave_repositories(void)
static int run_sql_fix_privilege_tables(void)
{
- int found_real_errors= 0;
+ int found_real_errors= 0, query_started= 0;
const char **query_ptr;
+ const char *end;
DYNAMIC_STRING ds_script;
DYNAMIC_STRING ds_result;
+ DYNAMIC_STRING ds_query;
DBUG_ENTER("run_sql_fix_privilege_tables");
- if (init_dynamic_string(&ds_script, "", 65536, 1024))
+ if (init_dynamic_string(&ds_script, "", 96*1024, 8196))
die("Out of memory");
- if (init_dynamic_string(&ds_result, "", 512, 512))
+ if (init_dynamic_string(&ds_result, "", 1024, 1024))
+ die("Out of memory");
+
+ if (init_dynamic_string(&ds_query, "", 1024, 1024))
die("Out of memory");
verbose("Phase %d/%d: Running 'mysql_fix_privilege_tables'",
@@ -1346,22 +1340,46 @@ static int run_sql_fix_privilege_tables(void)
"Unknown column" and "Duplicate key name" since they just
indicate the system tables are already up to date
*/
- char *line= ds_result.str;
+ const char *line= ds_result.str;
do
{
+ size_t length;
+ end= strchr(line, '\n');
+ if (!end)
+ end= strend(line);
+ else
+ end++; /* Include end \n */
+ length= (size_t) (end - line);
+
if (!is_expected_error(line))
{
/* Something unexpected failed, dump error line to screen */
found_real_errors++;
- print_line(line);
+ if (ds_query.length)
+ fwrite(ds_query.str, sizeof(char), ds_query.length, stderr);
+ fwrite(line, sizeof(char), length, stderr);
+ query_started= 0;
}
else if (strncmp(line, "WARNING", 7) == 0)
{
- print_line(line);
+ fwrite(line, sizeof(char), length, stderr);
+ query_started= 0;
}
- } while ((line= get_line(line)) && *line);
+ else if (!strncmp(line, "--------------\n", 16))
+ {
+ /* mariadb separates query from the error with a line of '-' */
+ if (!query_started++)
+ ds_query.length= 0; /* Truncate */
+ else
+ query_started= 0; /* End of query */
+ }
+ else if (query_started)
+ {
+ dynstr_append_mem(&ds_query, line, length);
+ }
+ } while (*(line= end));
}
-
+ dynstr_free(&ds_query);
dynstr_free(&ds_result);
dynstr_free(&ds_script);
DBUG_RETURN(found_real_errors);
diff --git a/mysql-test/main/mysqldump.result b/mysql-test/main/mysqldump.result
index 1541a4e6f72..1f59f31b7c8 100644
--- a/mysql-test/main/mysqldump.result
+++ b/mysql-test/main/mysqldump.result
@@ -6413,9 +6413,13 @@ j integer
INSERT INTO t VALUES (1,1),(2,2),(3,3),(4,4);
# Dump database 1
# Restore from database 1 to database 2
-ERROR 1100 (HY000) at line 46: Table 'seq_t_i' was not locked with LOCK TABLES
SETVAL(`seq_t_i`, 1, 0)
1
+--------------
+INSERT INTO `t` VALUES (1,1),(2,2),(3,3),(4,4)
+--------------
+
+ERROR 1100 (HY000) at line 46: Table 'seq_t_i' was not locked with LOCK TABLES
DROP DATABASE IF EXISTS test1;
DROP DATABASE IF EXISTS test2;
#
From 956bcf8f49982ab99884321eb3f58dcfef3630ef Mon Sep 17 00:00:00 2001
From: Monty <monty@mariadb.org>
Date: Sat, 15 Jun 2024 16:55:08 +0300
Subject: [PATCH 4/4] Change mysqldump to use DO instead of 'SELECT' for
storing sequences.
This avoids a lot of SETVAL() results when applying a mysqldump with
sequences.
---
client/mysqldump.c | 2 +-
mysql-test/main/mysql.result | 8 ++++++
mysql-test/main/mysqldump.result | 26 -------------------
.../suite/sql_sequence/mysqldump.result | 16 ++++++------
4 files changed, 17 insertions(+), 35 deletions(-)
diff --git a/client/mysqldump.c b/client/mysqldump.c
index 521e048497d..1c9d92d6e09 100644
--- a/client/mysqldump.c
+++ b/client/mysqldump.c
@@ -2959,7 +2959,7 @@ static void get_sequence_structure(const char *seq, const char *db)
row= mysql_fetch_row(result);
if (row[0])
{
- fprintf(sql_file, "SELECT SETVAL(%s, %s, 0);\n", result_seq, row[0]);
+ fprintf(sql_file, "DO SETVAL(%s, %s, 0);\n", result_seq, row[0]);
}
// Sequences will not use inserts, so no need for REPLACE and LOCKS
mysql_free_result(result);
diff --git a/mysql-test/main/mysql.result b/mysql-test/main/mysql.result
index 445aa602241..0bb447df47a 100644
--- a/mysql-test/main/mysql.result
+++ b/mysql-test/main/mysql.result
@@ -137,6 +137,10 @@ c int(11) YES NULL
drop table t1;
1
1
+--------------
+ use
+--------------
+
ERROR 1064 (42000) at line 3: You have an error in your SQL syntax; check the manual that corresponds to your MariaDB server version for the right syntax to use near '' at line 1
ERROR at line 1: USE must be followed by a database name
1 +1
@@ -166,6 +170,10 @@ count(*)
drop table t17583;
Test connect without db- or host-name => reconnect
Test connect with dbname only => new dbname, old hostname
+--------------
+connecttest
+--------------
+
ERROR 1064 (42000) at line 1: You have an error in your SQL syntax; check the manual that corresponds to your MariaDB server version for the right syntax to use near 'connecttest' at line 1
Test connect with _invalid_ dbname only => new invalid dbname, old hostname
ERROR 1049 (42000) at line 1: Unknown database 'invalid'
diff --git a/mysql-test/main/mysqldump.result b/mysql-test/main/mysqldump.result
index 1f59f31b7c8..b69e6168c86 100644
--- a/mysql-test/main/mysqldump.result
+++ b/mysql-test/main/mysqldump.result
@@ -6326,14 +6326,6 @@ Table Create Table
s4 CREATE SEQUENCE `s4` start with 400 minvalue 400 maxvalue 1400 increment by 40 cache 1000 cycle ENGINE=MyISAM
# Dump sequence without `--no-data`
# Restore from mysqldump
-SETVAL(`s1`, 1101, 0)
-1101
-SETVAL(`s2`, 1201, 0)
-1201
-SETVAL(`s3`, 1301, 0)
-1301
-SETVAL(`s4`, 1401, 0)
-1401
# Show create after restore
show create sequence d.s1;
Table Create Table
@@ -6352,14 +6344,6 @@ NEXTVAL(d.s1) NEXTVAL(d.s2) NEXTVAL(d.s3) NEXTVAL(d.s4)
100 200 300 400
# Dump sequence with `--no-data`
# Restore from mysqldump
-SETVAL(`s1`, 1101, 0)
-1101
-SETVAL(`s2`, 1201, 0)
-1201
-SETVAL(`s3`, 1301, 0)
-1301
-SETVAL(`s4`, 1401, 0)
-1401
# Show create after restore `--no-data`
show create sequence d.s1;
Table Create Table
@@ -6378,14 +6362,6 @@ NEXTVAL(d.s1) NEXTVAL(d.s2) NEXTVAL(d.s3) NEXTVAL(d.s4)
100 200 300 400
# Restore to different database than original
create database d2;
-SETVAL(`s1`, 1101, 0)
-1101
-SETVAL(`s2`, 1201, 0)
-1201
-SETVAL(`s3`, 1301, 0)
-1301
-SETVAL(`s4`, 1401, 0)
-1401
show create sequence d2.s1;
Table Create Table
s1 CREATE SEQUENCE `s1` start with 100 minvalue 100 maxvalue 1100 increment by 10 cache 1000 cycle ENGINE=MyISAM
@@ -6413,8 +6389,6 @@ j integer
INSERT INTO t VALUES (1,1),(2,2),(3,3),(4,4);
# Dump database 1
# Restore from database 1 to database 2
-SETVAL(`seq_t_i`, 1, 0)
-1
--------------
INSERT INTO `t` VALUES (1,1),(2,2),(3,3),(4,4)
--------------
diff --git a/mysql-test/suite/sql_sequence/mysqldump.result b/mysql-test/suite/sql_sequence/mysqldump.result
index b07f07a605b..ea100fb0199 100644
--- a/mysql-test/suite/sql_sequence/mysqldump.result
+++ b/mysql-test/suite/sql_sequence/mysqldump.result
@@ -5,9 +5,9 @@ CREATE SEQUENCE x1 engine=innodb;
# dump whole database
/*!999999\- enable the sandbox mode */
CREATE SEQUENCE `a1` start with 1 minvalue 1 maxvalue 9223372036854775806 increment by 1 cache 1000 nocycle ENGINE=Aria;
-SELECT SETVAL(`a1`, 1, 0);
+DO SETVAL(`a1`, 1, 0);
CREATE SEQUENCE `x1` start with 1 minvalue 1 maxvalue 9223372036854775806 increment by 1 cache 1000 nocycle ENGINE=InnoDB;
-SELECT SETVAL(`x1`, 1, 0);
+DO SETVAL(`x1`, 1, 0);
/*!40101 SET @saved_cs_client = @@character_set_client */;
/*!40101 SET character_set_client = utf8 */;
CREATE TABLE `t1` (
@@ -19,9 +19,9 @@ INSERT INTO `t1` VALUES (1),(2);
# dump by tables order 1
/*!999999\- enable the sandbox mode */
CREATE SEQUENCE `a1` start with 1 minvalue 1 maxvalue 9223372036854775806 increment by 1 cache 1000 nocycle ENGINE=Aria;
-SELECT SETVAL(`a1`, 1, 0);
+DO SETVAL(`a1`, 1, 0);
CREATE SEQUENCE `x1` start with 1 minvalue 1 maxvalue 9223372036854775806 increment by 1 cache 1000 nocycle ENGINE=InnoDB;
-SELECT SETVAL(`x1`, 1, 0);
+DO SETVAL(`x1`, 1, 0);
/*!40101 SET @saved_cs_client = @@character_set_client */;
/*!40101 SET character_set_client = utf8 */;
CREATE TABLE `t1` (
@@ -33,9 +33,9 @@ INSERT INTO `t1` VALUES (1),(2);
# dump by tables order 2
/*!999999\- enable the sandbox mode */
CREATE SEQUENCE `a1` start with 1 minvalue 1 maxvalue 9223372036854775806 increment by 1 cache 1000 nocycle ENGINE=Aria;
-SELECT SETVAL(`a1`, 1, 0);
+DO SETVAL(`a1`, 1, 0);
CREATE SEQUENCE `x1` start with 1 minvalue 1 maxvalue 9223372036854775806 increment by 1 cache 1000 nocycle ENGINE=InnoDB;
-SELECT SETVAL(`x1`, 1, 0);
+DO SETVAL(`x1`, 1, 0);
/*!40101 SET @saved_cs_client = @@character_set_client */;
/*!40101 SET character_set_client = utf8 */;
CREATE TABLE `t1` (
@@ -57,9 +57,9 @@ INSERT INTO `t1` VALUES (1),(2);
# dump by tables only sequences
/*!999999\- enable the sandbox mode */
CREATE SEQUENCE `a1` start with 1 minvalue 1 maxvalue 9223372036854775806 increment by 1 cache 1000 nocycle ENGINE=Aria;
-SELECT SETVAL(`a1`, 1, 0);
+DO SETVAL(`a1`, 1, 0);
CREATE SEQUENCE `x1` start with 1 minvalue 1 maxvalue 9223372036854775806 increment by 1 cache 1000 nocycle ENGINE=InnoDB;
-SELECT SETVAL(`x1`, 1, 0);
+DO SETVAL(`x1`, 1, 0);
# end of dumps
DROP TABLE a1,t1,x1;
set default_storage_engine=InnoDB;