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mariadb/sql/event_db_repository.cc
Dmitry Lenev 378cdc58c1 Patch that refactors global read lock implementation and fixes 
bug #57006 "Deadlock between HANDLER and FLUSH TABLES WITH READ
LOCK" and bug #54673 "It takes too long to get readlock for
'FLUSH TABLES WITH READ LOCK'".

The first bug manifested itself as a deadlock which occurred
when a connection, which had some table open through HANDLER
statement, tried to update some data through DML statement
while another connection tried to execute FLUSH TABLES WITH
READ LOCK concurrently.

What happened was that FTWRL in the second connection managed
to perform first step of GRL acquisition and thus blocked all
upcoming DML. After that it started to wait for table open
through HANDLER statement to be flushed. When the first connection
tried to execute DML it has started to wait for GRL/the second
connection creating deadlock.

The second bug manifested itself as starvation of FLUSH TABLES
WITH READ LOCK statements in cases when there was a constant
stream of concurrent DML statements (in two or more
connections).

This has happened because requests for protection against GRL
which were acquired by DML statements were ignoring presence of
pending GRL and thus the latter was starved.

This patch solves both these problems by re-implementing GRL
using metadata locks.

Similar to the old implementation acquisition of GRL in new
implementation is two-step. During the first step we block
all concurrent DML and DDL statements by acquiring global S
metadata lock (each DML and DDL statement acquires global IX
lock for its duration). During the second step we block commits
by acquiring global S lock in COMMIT namespace (commit code
acquires global IX lock in this namespace).

Note that unlike in old implementation acquisition of
protection against GRL in DML and DDL is semi-automatic.
We assume that any statement which should be blocked by GRL
will either open and acquires write-lock on tables or acquires
metadata locks on objects it is going to modify. For any such
statement global IX metadata lock is automatically acquired
for its duration.

The first problem is solved because waits for GRL become
visible to deadlock detector in metadata locking subsystem
and thus deadlocks like one in the first bug become impossible.

The second problem is solved because global S locks which
are used for GRL implementation are given preference over
IX locks which are acquired by concurrent DML (and we can
switch to fair scheduling in future if needed).

Important change:
FTWRL/GRL no longer blocks DML and DDL on temporary tables.
Before this patch behavior was not consistent in this respect:
in some cases DML/DDL statements on temporary tables were
blocked while in others they were not. Since the main use cases
for FTWRL are various forms of backups and temporary tables are
not preserved during backups we have opted for consistently
allowing DML/DDL on temporary tables during FTWRL/GRL.

Important change:
This patch changes thread state names which are used when
DML/DDL of FTWRL is waiting for global read lock. It is now
either "Waiting for global read lock" or "Waiting for commit
lock" depending on the stage on which FTWRL is.

Incompatible change:
To solve deadlock in events code which was exposed by this
patch we have to replace LOCK_event_metadata mutex with
metadata locks on events. As result we have to prohibit
DDL on events under LOCK TABLES.

This patch also adds extensive test coverage for interaction
of DML/DDL and FTWRL.

Performance of new and old global read lock implementations
in sysbench tests were compared. There were no significant
difference between new and old implementations.
2010-11-11 20:11:05 +03:00

1202 lines
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/* Copyright 2004-2008 MySQL AB, 2008 Sun Microsystems, Inc.
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; version 2 of the License.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA */
#include "sql_priv.h"
#include "unireg.h"
#include "sql_base.h" // close_thread_tables
#include "event_db_repository.h"
#include "key.h" // key_copy
#include "sql_db.h" // get_default_db_collation
#include "sql_time.h" // interval_type_to_name
#include "tztime.h" // struct Time_zone
#include "sql_acl.h" // SUPER_ACL, MYSQL_DB_FIELD_COUNT, mysql_db_table_fields
#include "records.h" // init_read_record, end_read_record
#include "sp_head.h"
#include "event_data_objects.h"
#include "events.h"
#include "sql_show.h"
#include "lock.h" // MYSQL_LOCK_IGNORE_TIMEOUT
/**
@addtogroup Event_Scheduler
@{
*/
static
const TABLE_FIELD_TYPE event_table_fields[ET_FIELD_COUNT] =
{
{
{ C_STRING_WITH_LEN("db") },
{ C_STRING_WITH_LEN("char(64)") },
{ C_STRING_WITH_LEN("utf8") }
},
{
{ C_STRING_WITH_LEN("name") },
{ C_STRING_WITH_LEN("char(64)") },
{ C_STRING_WITH_LEN("utf8") }
},
{
{ C_STRING_WITH_LEN("body") },
{ C_STRING_WITH_LEN("longblob") },
{NULL, 0}
},
{
{ C_STRING_WITH_LEN("definer") },
{ C_STRING_WITH_LEN("char(77)") },
{ C_STRING_WITH_LEN("utf8") }
},
{
{ C_STRING_WITH_LEN("execute_at") },
{ C_STRING_WITH_LEN("datetime") },
{NULL, 0}
},
{
{ C_STRING_WITH_LEN("interval_value") },
{ C_STRING_WITH_LEN("int(11)") },
{NULL, 0}
},
{
{ C_STRING_WITH_LEN("interval_field") },
{ C_STRING_WITH_LEN("enum('YEAR','QUARTER','MONTH','DAY',"
"'HOUR','MINUTE','WEEK','SECOND','MICROSECOND','YEAR_MONTH','DAY_HOUR',"
"'DAY_MINUTE','DAY_SECOND','HOUR_MINUTE','HOUR_SECOND','MINUTE_SECOND',"
"'DAY_MICROSECOND','HOUR_MICROSECOND','MINUTE_MICROSECOND',"
"'SECOND_MICROSECOND')") },
{NULL, 0}
},
{
{ C_STRING_WITH_LEN("created") },
{ C_STRING_WITH_LEN("timestamp") },
{NULL, 0}
},
{
{ C_STRING_WITH_LEN("modified") },
{ C_STRING_WITH_LEN("timestamp") },
{NULL, 0}
},
{
{ C_STRING_WITH_LEN("last_executed") },
{ C_STRING_WITH_LEN("datetime") },
{NULL, 0}
},
{
{ C_STRING_WITH_LEN("starts") },
{ C_STRING_WITH_LEN("datetime") },
{NULL, 0}
},
{
{ C_STRING_WITH_LEN("ends") },
{ C_STRING_WITH_LEN("datetime") },
{NULL, 0}
},
{
{ C_STRING_WITH_LEN("status") },
{ C_STRING_WITH_LEN("enum('ENABLED','DISABLED','SLAVESIDE_DISABLED')") },
{NULL, 0}
},
{
{ C_STRING_WITH_LEN("on_completion") },
{ C_STRING_WITH_LEN("enum('DROP','PRESERVE')") },
{NULL, 0}
},
{
{ C_STRING_WITH_LEN("sql_mode") },
{ C_STRING_WITH_LEN("set('REAL_AS_FLOAT','PIPES_AS_CONCAT','ANSI_QUOTES',"
"'IGNORE_SPACE','NOT_USED','ONLY_FULL_GROUP_BY','NO_UNSIGNED_SUBTRACTION',"
"'NO_DIR_IN_CREATE','POSTGRESQL','ORACLE','MSSQL','DB2','MAXDB',"
"'NO_KEY_OPTIONS','NO_TABLE_OPTIONS','NO_FIELD_OPTIONS','MYSQL323','MYSQL40',"
"'ANSI','NO_AUTO_VALUE_ON_ZERO','NO_BACKSLASH_ESCAPES','STRICT_TRANS_TABLES',"
"'STRICT_ALL_TABLES','NO_ZERO_IN_DATE','NO_ZERO_DATE','INVALID_DATES',"
"'ERROR_FOR_DIVISION_BY_ZERO','TRADITIONAL','NO_AUTO_CREATE_USER',"
"'HIGH_NOT_PRECEDENCE','NO_ENGINE_SUBSTITUTION','PAD_CHAR_TO_FULL_LENGTH')") },
{NULL, 0}
},
{
{ C_STRING_WITH_LEN("comment") },
{ C_STRING_WITH_LEN("char(64)") },
{ C_STRING_WITH_LEN("utf8") }
},
{
{ C_STRING_WITH_LEN("originator") },
{ C_STRING_WITH_LEN("int(10)") },
{NULL, 0}
},
{
{ C_STRING_WITH_LEN("time_zone") },
{ C_STRING_WITH_LEN("char(64)") },
{ C_STRING_WITH_LEN("latin1") }
},
{
{ C_STRING_WITH_LEN("character_set_client") },
{ C_STRING_WITH_LEN("char(32)") },
{ C_STRING_WITH_LEN("utf8") }
},
{
{ C_STRING_WITH_LEN("collation_connection") },
{ C_STRING_WITH_LEN("char(32)") },
{ C_STRING_WITH_LEN("utf8") }
},
{
{ C_STRING_WITH_LEN("db_collation") },
{ C_STRING_WITH_LEN("char(32)") },
{ C_STRING_WITH_LEN("utf8") }
},
{
{ C_STRING_WITH_LEN("body_utf8") },
{ C_STRING_WITH_LEN("longblob") },
{ NULL, 0 }
}
};
static const TABLE_FIELD_DEF
event_table_def= {ET_FIELD_COUNT, event_table_fields};
class Event_db_intact : public Table_check_intact
{
protected:
void report_error(uint, const char *fmt, ...)
{
va_list args;
va_start(args, fmt);
error_log_print(ERROR_LEVEL, fmt, args);
va_end(args);
}
};
/** In case of an error, a message is printed to the error log. */
static Event_db_intact table_intact;
/**
Puts some data common to CREATE and ALTER EVENT into a row.
Used both when an event is created and when it is altered.
@param thd THD
@param table The row to fill out
@param et Event's data
@param sp Event stored routine
@param is_update CREATE EVENT or ALTER EVENT
@retval FALSE success
@retval TRUE error
*/
static bool
mysql_event_fill_row(THD *thd,
TABLE *table,
Event_parse_data *et,
sp_head *sp,
ulong sql_mode,
my_bool is_update)
{
CHARSET_INFO *scs= system_charset_info;
enum enum_events_table_field f_num;
Field **fields= table->field;
int rs= FALSE;
DBUG_ENTER("mysql_event_fill_row");
DBUG_PRINT("info", ("dbname=[%s]", et->dbname.str));
DBUG_PRINT("info", ("name =[%s]", et->name.str));
DBUG_ASSERT(et->on_completion != Event_parse_data::ON_COMPLETION_DEFAULT);
if (table->s->fields < ET_FIELD_COUNT)
{
/*
Safety: this can only happen if someone started the server
and then altered mysql.event.
*/
my_error(ER_COL_COUNT_DOESNT_MATCH_CORRUPTED, MYF(0), table->alias,
(int) ET_FIELD_COUNT, table->s->fields);
DBUG_RETURN(TRUE);
}
if (fields[f_num= ET_FIELD_DEFINER]->
store(et->definer.str, et->definer.length, scs))
goto err_truncate;
if (fields[f_num= ET_FIELD_DB]->store(et->dbname.str, et->dbname.length, scs))
goto err_truncate;
if (fields[f_num= ET_FIELD_NAME]->store(et->name.str, et->name.length, scs))
goto err_truncate;
/* both ON_COMPLETION and STATUS are NOT NULL thus not calling set_notnull()*/
rs|= fields[ET_FIELD_ON_COMPLETION]->store((longlong)et->on_completion, TRUE);
rs|= fields[ET_FIELD_STATUS]->store((longlong)et->status, TRUE);
rs|= fields[ET_FIELD_ORIGINATOR]->store((longlong)et->originator, TRUE);
/*
Change the SQL_MODE only if body was present in an ALTER EVENT and of course
always during CREATE EVENT.
*/
if (et->body_changed)
{
DBUG_ASSERT(sp->m_body.str);
rs|= fields[ET_FIELD_SQL_MODE]->store((longlong)sql_mode, TRUE);
if (fields[f_num= ET_FIELD_BODY]->store(sp->m_body.str,
sp->m_body.length,
scs))
{
goto err_truncate;
}
}
if (et->expression)
{
const String *tz_name= thd->variables.time_zone->get_name();
if (!is_update || !et->starts_null)
{
fields[ET_FIELD_TIME_ZONE]->set_notnull();
rs|= fields[ET_FIELD_TIME_ZONE]->store(tz_name->ptr(), tz_name->length(),
tz_name->charset());
}
fields[ET_FIELD_INTERVAL_EXPR]->set_notnull();
rs|= fields[ET_FIELD_INTERVAL_EXPR]->store((longlong)et->expression, TRUE);
fields[ET_FIELD_TRANSIENT_INTERVAL]->set_notnull();
rs|= fields[ET_FIELD_TRANSIENT_INTERVAL]->
store(interval_type_to_name[et->interval].str,
interval_type_to_name[et->interval].length,
scs);
fields[ET_FIELD_EXECUTE_AT]->set_null();
if (!et->starts_null)
{
MYSQL_TIME time;
my_tz_OFFSET0->gmt_sec_to_TIME(&time, et->starts);
fields[ET_FIELD_STARTS]->set_notnull();
fields[ET_FIELD_STARTS]->store_time(&time, MYSQL_TIMESTAMP_DATETIME);
}
if (!et->ends_null)
{
MYSQL_TIME time;
my_tz_OFFSET0->gmt_sec_to_TIME(&time, et->ends);
fields[ET_FIELD_ENDS]->set_notnull();
fields[ET_FIELD_ENDS]->store_time(&time, MYSQL_TIMESTAMP_DATETIME);
}
}
else if (et->execute_at)
{
const String *tz_name= thd->variables.time_zone->get_name();
fields[ET_FIELD_TIME_ZONE]->set_notnull();
rs|= fields[ET_FIELD_TIME_ZONE]->store(tz_name->ptr(), tz_name->length(),
tz_name->charset());
fields[ET_FIELD_INTERVAL_EXPR]->set_null();
fields[ET_FIELD_TRANSIENT_INTERVAL]->set_null();
fields[ET_FIELD_STARTS]->set_null();
fields[ET_FIELD_ENDS]->set_null();
MYSQL_TIME time;
my_tz_OFFSET0->gmt_sec_to_TIME(&time, et->execute_at);
fields[ET_FIELD_EXECUTE_AT]->set_notnull();
fields[ET_FIELD_EXECUTE_AT]->
store_time(&time, MYSQL_TIMESTAMP_DATETIME);
}
else
{
DBUG_ASSERT(is_update);
/*
it is normal to be here when the action is update
this is an error if the action is create. something is borked
*/
}
((Field_timestamp *)fields[ET_FIELD_MODIFIED])->set_time();
if (et->comment.str)
{
if (fields[f_num= ET_FIELD_COMMENT]->
store(et->comment.str, et->comment.length, scs))
goto err_truncate;
}
fields[ET_FIELD_CHARACTER_SET_CLIENT]->set_notnull();
rs|= fields[ET_FIELD_CHARACTER_SET_CLIENT]->store(
thd->variables.character_set_client->csname,
strlen(thd->variables.character_set_client->csname),
system_charset_info);
fields[ET_FIELD_COLLATION_CONNECTION]->set_notnull();
rs|= fields[ET_FIELD_COLLATION_CONNECTION]->store(
thd->variables.collation_connection->name,
strlen(thd->variables.collation_connection->name),
system_charset_info);
{
CHARSET_INFO *db_cl= get_default_db_collation(thd, et->dbname.str);
fields[ET_FIELD_DB_COLLATION]->set_notnull();
rs|= fields[ET_FIELD_DB_COLLATION]->store(db_cl->name,
strlen(db_cl->name),
system_charset_info);
}
if (et->body_changed)
{
fields[ET_FIELD_BODY_UTF8]->set_notnull();
rs|= fields[ET_FIELD_BODY_UTF8]->store(sp->m_body_utf8.str,
sp->m_body_utf8.length,
system_charset_info);
}
if (rs)
{
my_error(ER_EVENT_STORE_FAILED, MYF(0), fields[f_num]->field_name, rs);
DBUG_RETURN(TRUE);
}
DBUG_RETURN(FALSE);
err_truncate:
my_error(ER_EVENT_DATA_TOO_LONG, MYF(0), fields[f_num]->field_name);
DBUG_RETURN(TRUE);
}
/*
Performs an index scan of event_table (mysql.event) and fills schema_table.
SYNOPSIS
Event_db_repository::index_read_for_db_for_i_s()
thd Thread
schema_table The I_S.EVENTS table
event_table The event table to use for loading (mysql.event)
db For which schema to do an index scan.
RETURN VALUE
0 OK
1 Error
*/
bool
Event_db_repository::index_read_for_db_for_i_s(THD *thd, TABLE *schema_table,
TABLE *event_table,
const char *db)
{
int ret=0;
CHARSET_INFO *scs= system_charset_info;
KEY *key_info;
uint key_len;
uchar *key_buf= NULL;
LINT_INIT(key_buf);
DBUG_ENTER("Event_db_repository::index_read_for_db_for_i_s");
DBUG_PRINT("info", ("Using prefix scanning on PK"));
event_table->file->ha_index_init(0, 1);
key_info= event_table->key_info;
if (key_info->key_parts == 0 ||
key_info->key_part[0].field != event_table->field[ET_FIELD_DB])
{
/* Corrupted table: no index or index on a wrong column */
my_error(ER_CANNOT_LOAD_FROM_TABLE, MYF(0), "event");
ret= 1;
goto end;
}
event_table->field[ET_FIELD_DB]->store(db, strlen(db), scs);
key_len= key_info->key_part[0].store_length;
if (!(key_buf= (uchar *)alloc_root(thd->mem_root, key_len)))
{
/* Don't send error, it would be done by sql_alloc_error_handler() */
ret= 1;
goto end;
}
key_copy(key_buf, event_table->record[0], key_info, key_len);
if (!(ret= event_table->file->index_read_map(event_table->record[0], key_buf,
(key_part_map)1,
HA_READ_PREFIX)))
{
DBUG_PRINT("info",("Found rows. Let's retrieve them. ret=%d", ret));
do
{
ret= copy_event_to_schema_table(thd, schema_table, event_table);
if (ret == 0)
ret= event_table->file->index_next_same(event_table->record[0],
key_buf, key_len);
} while (ret == 0);
}
DBUG_PRINT("info", ("Scan finished. ret=%d", ret));
/* ret is guaranteed to be != 0 */
if (ret == HA_ERR_END_OF_FILE || ret == HA_ERR_KEY_NOT_FOUND)
ret= 0;
else
event_table->file->print_error(ret, MYF(0));
end:
event_table->file->ha_index_end();
DBUG_RETURN(test(ret));
}
/*
Performs a table scan of event_table (mysql.event) and fills schema_table.
SYNOPSIS
Events_db_repository::table_scan_all_for_i_s()
thd Thread
schema_table The I_S.EVENTS in memory table
event_table The event table to use for loading.
RETURN VALUE
FALSE OK
TRUE Error
*/
bool
Event_db_repository::table_scan_all_for_i_s(THD *thd, TABLE *schema_table,
TABLE *event_table)
{
int ret;
READ_RECORD read_record_info;
DBUG_ENTER("Event_db_repository::table_scan_all_for_i_s");
init_read_record(&read_record_info, thd, event_table, NULL, 1, 0, FALSE);
/*
rr_sequential, in read_record(), returns 137==HA_ERR_END_OF_FILE,
but rr_handle_error returns -1 for that reason. Thus, read_record()
returns -1 eventually.
*/
do
{
ret= read_record_info.read_record(&read_record_info);
if (ret == 0)
ret= copy_event_to_schema_table(thd, schema_table, event_table);
} while (ret == 0);
DBUG_PRINT("info", ("Scan finished. ret=%d", ret));
end_read_record(&read_record_info);
/* ret is guaranteed to be != 0 */
DBUG_RETURN(ret == -1? FALSE:TRUE);
}
/**
Fills I_S.EVENTS with data loaded from mysql.event. Also used by
SHOW EVENTS
The reason we reset and backup open tables here is that this
function may be called from any query that accesses
INFORMATION_SCHEMA - including a query that is issued from
a pre-locked statement, one that already has open and locked
tables.
@retval FALSE success
@retval TRUE error
*/
bool
Event_db_repository::fill_schema_events(THD *thd, TABLE_LIST *i_s_table,
const char *db)
{
TABLE *schema_table= i_s_table->table;
Open_tables_backup open_tables_backup;
TABLE_LIST event_table;
int ret= 0;
DBUG_ENTER("Event_db_repository::fill_schema_events");
DBUG_PRINT("info",("db=%s", db? db:"(null)"));
event_table.init_one_table("mysql", 5, "event", 5, "event", TL_READ);
if (open_system_tables_for_read(thd, &event_table, &open_tables_backup))
DBUG_RETURN(TRUE);
/*
1. SELECT I_S => use table scan. I_S.EVENTS does not guarantee order
thus we won't order it. OTOH, SHOW EVENTS will be
ordered.
2. SHOW EVENTS => PRIMARY KEY with prefix scanning on (db)
Reasoning: Events are per schema, therefore a scan over an index
will save use from doing a table scan and comparing
every single row's `db` with the schema which we show.
*/
if (db)
ret= index_read_for_db_for_i_s(thd, schema_table, event_table.table, db);
else
ret= table_scan_all_for_i_s(thd, schema_table, event_table.table);
close_system_tables(thd, &open_tables_backup);
DBUG_PRINT("info", ("Return code=%d", ret));
DBUG_RETURN(ret);
}
/**
Open mysql.event table for read.
It's assumed that the caller knows what they are doing:
- whether it was necessary to reset-and-backup the open tables state
- whether the requested lock does not lead to a deadlock
- whether this open mode would work under LOCK TABLES, or inside a
stored function or trigger.
Note that if the table can't be locked successfully this operation will
close it. Therefore it provides guarantee that it either opens and locks
table or fails without leaving any tables open.
@param[in] thd Thread context
@param[in] lock_type How to lock the table
@param[out] table We will store the open table here
@retval TRUE open and lock failed - an error message is pushed into the
stack
@retval FALSE success
*/
bool
Event_db_repository::open_event_table(THD *thd, enum thr_lock_type lock_type,
TABLE **table)
{
TABLE_LIST tables;
DBUG_ENTER("Event_db_repository::open_event_table");
tables.init_one_table("mysql", 5, "event", 5, "event", lock_type);
if (open_and_lock_tables(thd, &tables, FALSE, MYSQL_LOCK_IGNORE_TIMEOUT))
DBUG_RETURN(TRUE);
*table= tables.table;
tables.table->use_all_columns();
DBUG_RETURN(FALSE);
}
/**
Creates an event record in mysql.event table.
Creates an event. Relies on mysql_event_fill_row which is shared with
::update_event.
@pre All semantic checks must be performed outside. This function
only creates a record on disk.
@pre The thread handle has no open tables.
@param[in,out] thd THD
@param[in] parse_data Parsed event definition
@param[in] create_if_not TRUE if IF NOT EXISTS clause was provided
to CREATE EVENT statement
@retval FALSE success
@retval TRUE error
*/
bool
Event_db_repository::create_event(THD *thd, Event_parse_data *parse_data,
my_bool create_if_not)
{
int ret= 1;
TABLE *table= NULL;
sp_head *sp= thd->lex->sphead;
ulong saved_mode= thd->variables.sql_mode;
/*
Take a savepoint to release only the lock on mysql.event
table at the end but keep the global read lock and
possible other locks taken by the caller.
*/
MDL_savepoint mdl_savepoint= thd->mdl_context.mdl_savepoint();
DBUG_ENTER("Event_db_repository::create_event");
DBUG_PRINT("info", ("open mysql.event for update"));
DBUG_ASSERT(sp);
/* Reset sql_mode during data dictionary operations. */
thd->variables.sql_mode= 0;
if (open_event_table(thd, TL_WRITE, &table))
goto end;
DBUG_PRINT("info", ("name: %.*s", (int) parse_data->name.length,
parse_data->name.str));
DBUG_PRINT("info", ("check existance of an event with the same name"));
if (!find_named_event(parse_data->dbname, parse_data->name, table))
{
if (create_if_not)
{
push_warning_printf(thd, MYSQL_ERROR::WARN_LEVEL_NOTE,
ER_EVENT_ALREADY_EXISTS, ER(ER_EVENT_ALREADY_EXISTS),
parse_data->name.str);
ret= 0;
}
else
my_error(ER_EVENT_ALREADY_EXISTS, MYF(0), parse_data->name.str);
goto end;
}
DBUG_PRINT("info", ("non-existent, go forward"));
restore_record(table, s->default_values); // Get default values for fields
if (system_charset_info->cset->
numchars(system_charset_info, parse_data->dbname.str,
parse_data->dbname.str + parse_data->dbname.length) >
table->field[ET_FIELD_DB]->char_length())
{
my_error(ER_TOO_LONG_IDENT, MYF(0), parse_data->dbname.str);
goto end;
}
if (system_charset_info->cset->
numchars(system_charset_info, parse_data->name.str,
parse_data->name.str + parse_data->name.length) >
table->field[ET_FIELD_NAME]->char_length())
{
my_error(ER_TOO_LONG_IDENT, MYF(0), parse_data->name.str);
goto end;
}
if (sp->m_body.length > table->field[ET_FIELD_BODY]->field_length)
{
my_error(ER_TOO_LONG_BODY, MYF(0), parse_data->name.str);
goto end;
}
((Field_timestamp *)table->field[ET_FIELD_CREATED])->set_time();
/*
mysql_event_fill_row() calls my_error() in case of error so no need to
handle it here
*/
if (mysql_event_fill_row(thd, table, parse_data, sp, saved_mode, FALSE))
goto end;
table->field[ET_FIELD_STATUS]->store((longlong)parse_data->status, TRUE);
if ((ret= table->file->ha_write_row(table->record[0])))
{
table->file->print_error(ret, MYF(0));
goto end;
}
ret= 0;
end:
close_thread_tables(thd);
thd->mdl_context.rollback_to_savepoint(mdl_savepoint);
thd->variables.sql_mode= saved_mode;
DBUG_RETURN(test(ret));
}
/**
Used to execute ALTER EVENT. Pendant to Events::update_event().
@param[in,out] thd thread handle
@param[in] parse_data parsed event definition
@param[in] new_dbname not NULL if ALTER EVENT RENAME
points at a new database name
@param[in] new_name not NULL if ALTER EVENT RENAME
points at a new event name
@pre All semantic checks are performed outside this function,
it only updates the event definition on disk.
@pre We don't have any tables open in the given thread.
@retval FALSE success
@retval TRUE error (reported)
*/
bool
Event_db_repository::update_event(THD *thd, Event_parse_data *parse_data,
LEX_STRING *new_dbname,
LEX_STRING *new_name)
{
CHARSET_INFO *scs= system_charset_info;
TABLE *table= NULL;
sp_head *sp= thd->lex->sphead;
ulong saved_mode= thd->variables.sql_mode;
/*
Take a savepoint to release only the lock on mysql.event
table at the end but keep the global read lock and
possible other locks taken by the caller.
*/
MDL_savepoint mdl_savepoint= thd->mdl_context.mdl_savepoint();
int ret= 1;
DBUG_ENTER("Event_db_repository::update_event");
/* None or both must be set */
DBUG_ASSERT((new_dbname && new_name) || new_dbname == new_name);
/* Reset sql_mode during data dictionary operations. */
thd->variables.sql_mode= 0;
if (open_event_table(thd, TL_WRITE, &table))
goto end;
DBUG_PRINT("info", ("dbname: %s", parse_data->dbname.str));
DBUG_PRINT("info", ("name: %s", parse_data->name.str));
DBUG_PRINT("info", ("user: %s", parse_data->definer.str));
/* first look whether we overwrite */
if (new_name)
{
DBUG_PRINT("info", ("rename to: %s@%s", new_dbname->str, new_name->str));
if (!find_named_event(*new_dbname, *new_name, table))
{
my_error(ER_EVENT_ALREADY_EXISTS, MYF(0), new_name->str);
goto end;
}
}
/*
...and then if there is such an event. Don't exchange the blocks
because you will get error 120 from table handler because new_name will
overwrite the key and SE will tell us that it cannot find the already found
row (copied into record[1] later
*/
if (find_named_event(parse_data->dbname, parse_data->name, table))
{
my_error(ER_EVENT_DOES_NOT_EXIST, MYF(0), parse_data->name.str);
goto end;
}
store_record(table,record[1]);
/*
We check whether ALTER EVENT was given dates that are in the past.
However to know how to react, we need the ON COMPLETION type. The
check is deferred to this point because by now we have the previous
setting (from the event-table) to fall back on if nothing was specified
in the ALTER EVENT-statement.
*/
if (parse_data->check_dates(thd,
(int) table->field[ET_FIELD_ON_COMPLETION]->val_int()))
goto end;
/* Don't update create on row update. */
table->timestamp_field_type= TIMESTAMP_NO_AUTO_SET;
/*
mysql_event_fill_row() calls my_error() in case of error so no need to
handle it here
*/
if (mysql_event_fill_row(thd, table, parse_data, sp, saved_mode, TRUE))
goto end;
if (new_dbname)
{
table->field[ET_FIELD_DB]->store(new_dbname->str, new_dbname->length, scs);
table->field[ET_FIELD_NAME]->store(new_name->str, new_name->length, scs);
}
if ((ret= table->file->ha_update_row(table->record[1], table->record[0])))
{
table->file->print_error(ret, MYF(0));
goto end;
}
ret= 0;
end:
close_thread_tables(thd);
thd->mdl_context.rollback_to_savepoint(mdl_savepoint);
thd->variables.sql_mode= saved_mode;
DBUG_RETURN(test(ret));
}
/**
Delete event record from mysql.event table.
@param[in,out] thd thread handle
@param[in] db Database name
@param[in] name Event name
@param[in] drop_if_exists DROP IF EXISTS clause was specified.
If set, and the event does not exist,
the error is downgraded to a warning.
@retval FALSE success
@retval TRUE error (reported)
*/
bool
Event_db_repository::drop_event(THD *thd, LEX_STRING db, LEX_STRING name,
bool drop_if_exists)
{
TABLE *table= NULL;
/*
Take a savepoint to release only the lock on mysql.event
table at the end but keep the global read lock and
possible other locks taken by the caller.
*/
MDL_savepoint mdl_savepoint= thd->mdl_context.mdl_savepoint();
int ret= 1;
DBUG_ENTER("Event_db_repository::drop_event");
DBUG_PRINT("enter", ("%s@%s", db.str, name.str));
if (open_event_table(thd, TL_WRITE, &table))
goto end;
if (!find_named_event(db, name, table))
{
if ((ret= table->file->ha_delete_row(table->record[0])))
table->file->print_error(ret, MYF(0));
goto end;
}
/* Event not found */
if (!drop_if_exists)
{
my_error(ER_EVENT_DOES_NOT_EXIST, MYF(0), name.str);
goto end;
}
push_warning_printf(thd, MYSQL_ERROR::WARN_LEVEL_NOTE,
ER_SP_DOES_NOT_EXIST, ER(ER_SP_DOES_NOT_EXIST),
"Event", name.str);
ret= 0;
end:
close_thread_tables(thd);
thd->mdl_context.rollback_to_savepoint(mdl_savepoint);
DBUG_RETURN(test(ret));
}
/**
Positions the internal pointer of `table` to the place where (db, name)
is stored.
In case search succeeded, the table cursor points at the found row.
@param[in] db database name
@param[in] name event name
@param[in,out] table mysql.event table
@retval FALSE an event with such db/name key exists
@retval TRUE no record found or an error occured.
*/
bool
Event_db_repository::find_named_event(LEX_STRING db, LEX_STRING name,
TABLE *table)
{
uchar key[MAX_KEY_LENGTH];
DBUG_ENTER("Event_db_repository::find_named_event");
DBUG_PRINT("enter", ("name: %.*s", (int) name.length, name.str));
/*
Create key to find row. We have to use field->store() to be able to
handle VARCHAR and CHAR fields.
Assumption here is that the two first fields in the table are
'db' and 'name' and the first key is the primary key over the
same fields.
*/
if (db.length > table->field[ET_FIELD_DB]->field_length ||
name.length > table->field[ET_FIELD_NAME]->field_length)
DBUG_RETURN(TRUE);
table->field[ET_FIELD_DB]->store(db.str, db.length, &my_charset_bin);
table->field[ET_FIELD_NAME]->store(name.str, name.length, &my_charset_bin);
key_copy(key, table->record[0], table->key_info, table->key_info->key_length);
if (table->file->index_read_idx_map(table->record[0], 0, key, HA_WHOLE_KEY,
HA_READ_KEY_EXACT))
{
DBUG_PRINT("info", ("Row not found"));
DBUG_RETURN(TRUE);
}
DBUG_PRINT("info", ("Row found!"));
DBUG_RETURN(FALSE);
}
/*
Drops all events in the selected database, from mysql.event.
SYNOPSIS
Event_db_repository::drop_schema_events()
thd Thread
schema The database to clean from events
*/
void
Event_db_repository::drop_schema_events(THD *thd, LEX_STRING schema)
{
int ret= 0;
TABLE *table= NULL;
READ_RECORD read_record_info;
enum enum_events_table_field field= ET_FIELD_DB;
MDL_savepoint mdl_savepoint= thd->mdl_context.mdl_savepoint();
DBUG_ENTER("Event_db_repository::drop_schema_events");
DBUG_PRINT("enter", ("field=%d schema=%s", field, schema.str));
if (open_event_table(thd, TL_WRITE, &table))
DBUG_VOID_RETURN;
/* only enabled events are in memory, so we go now and delete the rest */
init_read_record(&read_record_info, thd, table, NULL, 1, 0, FALSE);
while (!ret && !(read_record_info.read_record(&read_record_info)) )
{
char *et_field= get_field(thd->mem_root, table->field[field]);
/* et_field may be NULL if the table is corrupted or out of memory */
if (et_field)
{
LEX_STRING et_field_lex= { et_field, strlen(et_field) };
DBUG_PRINT("info", ("Current event %s name=%s", et_field,
get_field(thd->mem_root,
table->field[ET_FIELD_NAME])));
if (!sortcmp_lex_string(et_field_lex, schema, system_charset_info))
{
DBUG_PRINT("info", ("Dropping"));
if ((ret= table->file->ha_delete_row(table->record[0])))
table->file->print_error(ret, MYF(0));
}
}
}
end_read_record(&read_record_info);
close_thread_tables(thd);
/*
Make sure to only release the MDL lock on mysql.event, not other
metadata locks DROP DATABASE might have acquired.
*/
thd->mdl_context.rollback_to_savepoint(mdl_savepoint);
DBUG_VOID_RETURN;
}
/**
Looks for a named event in mysql.event and then loads it from
the table.
@pre The given thread does not have open tables.
@retval FALSE success
@retval TRUE error
*/
bool
Event_db_repository::load_named_event(THD *thd, LEX_STRING dbname,
LEX_STRING name, Event_basic *etn)
{
bool ret;
ulong saved_mode= thd->variables.sql_mode;
Open_tables_backup open_tables_backup;
TABLE_LIST event_table;
DBUG_ENTER("Event_db_repository::load_named_event");
DBUG_PRINT("enter",("thd: 0x%lx name: %*s", (long) thd,
(int) name.length, name.str));
event_table.init_one_table("mysql", 5, "event", 5, "event", TL_READ);
/* Reset sql_mode during data dictionary operations. */
thd->variables.sql_mode= 0;
/*
We don't use open_event_table() here to make sure that SHOW
CREATE EVENT works properly in transactional context, and
does not release transactional metadata locks when the
event table is closed.
*/
if (!(ret= open_system_tables_for_read(thd, &event_table, &open_tables_backup)))
{
if ((ret= find_named_event(dbname, name, event_table.table)))
my_error(ER_EVENT_DOES_NOT_EXIST, MYF(0), name.str);
else if ((ret= etn->load_from_row(thd, event_table.table)))
my_error(ER_CANNOT_LOAD_FROM_TABLE, MYF(0), "event");
close_system_tables(thd, &open_tables_backup);
}
thd->variables.sql_mode= saved_mode;
DBUG_RETURN(ret);
}
/**
Update the event record in mysql.event table with a changed status
and/or last execution time.
@pre The thread handle does not have open tables.
*/
bool
Event_db_repository::
update_timing_fields_for_event(THD *thd,
LEX_STRING event_db_name,
LEX_STRING event_name,
my_time_t last_executed,
ulonglong status)
{
TABLE *table= NULL;
Field **fields;
int ret= 1;
bool save_binlog_row_based;
MYSQL_TIME time;
DBUG_ENTER("Event_db_repository::update_timing_fields_for_event");
/*
Turn off row binlogging of event timing updates. These are not used
for RBR of events replicated to the slave.
*/
if ((save_binlog_row_based= thd->is_current_stmt_binlog_format_row()))
thd->clear_current_stmt_binlog_format_row();
DBUG_ASSERT(thd->security_ctx->master_access & SUPER_ACL);
if (open_event_table(thd, TL_WRITE, &table))
goto end;
fields= table->field;
if (find_named_event(event_db_name, event_name, table))
goto end;
store_record(table, record[1]);
/* Don't update create on row update. */
table->timestamp_field_type= TIMESTAMP_NO_AUTO_SET;
my_tz_OFFSET0->gmt_sec_to_TIME(&time, last_executed);
fields[ET_FIELD_LAST_EXECUTED]->set_notnull();
fields[ET_FIELD_LAST_EXECUTED]->store_time(&time, MYSQL_TIMESTAMP_DATETIME);
fields[ET_FIELD_STATUS]->set_notnull();
fields[ET_FIELD_STATUS]->store(status, TRUE);
if ((ret= table->file->ha_update_row(table->record[1], table->record[0])))
{
table->file->print_error(ret, MYF(0));
goto end;
}
ret= 0;
end:
if (table)
close_mysql_tables(thd);
/* Restore the state of binlog format */
DBUG_ASSERT(!thd->is_current_stmt_binlog_format_row());
if (save_binlog_row_based)
thd->set_current_stmt_binlog_format_row();
DBUG_RETURN(test(ret));
}
/**
Open mysql.db, mysql.user and mysql.event and check whether:
- mysql.db exists and is up to date (or from a newer version of MySQL),
- mysql.user has column Event_priv at an expected position,
- mysql.event exists and is up to date (or from a newer version of
MySQL)
This function is called only when the server is started.
@pre The passed in thread handle has no open tables.
@retval FALSE OK
@retval TRUE Error, an error message is output to the error log.
*/
bool
Event_db_repository::check_system_tables(THD *thd)
{
TABLE_LIST tables;
int ret= FALSE;
const unsigned int event_priv_column_position= 29;
DBUG_ENTER("Event_db_repository::check_system_tables");
DBUG_PRINT("enter", ("thd: 0x%lx", (long) thd));
/* Check mysql.db */
tables.init_one_table("mysql", 5, "db", 2, "db", TL_READ);
if (open_and_lock_tables(thd, &tables, FALSE, MYSQL_LOCK_IGNORE_TIMEOUT))
{
ret= 1;
sql_print_error("Cannot open mysql.db");
}
else
{
if (table_intact.check(tables.table, &mysql_db_table_def))
ret= 1;
close_mysql_tables(thd);
}
/* Check mysql.user */
tables.init_one_table("mysql", 5, "user", 4, "user", TL_READ);
if (open_and_lock_tables(thd, &tables, FALSE, MYSQL_LOCK_IGNORE_TIMEOUT))
{
ret= 1;
sql_print_error("Cannot open mysql.user");
}
else
{
if (tables.table->s->fields < event_priv_column_position ||
strncmp(tables.table->field[event_priv_column_position]->field_name,
STRING_WITH_LEN("Event_priv")))
{
sql_print_error("mysql.user has no `Event_priv` column at position %d",
event_priv_column_position);
ret= 1;
}
close_mysql_tables(thd);
}
/* Check mysql.event */
tables.init_one_table("mysql", 5, "event", 5, "event", TL_READ);
if (open_and_lock_tables(thd, &tables, FALSE, MYSQL_LOCK_IGNORE_TIMEOUT))
{
ret= 1;
sql_print_error("Cannot open mysql.event");
}
else
{
if (table_intact.check(tables.table, &event_table_def))
ret= 1;
close_mysql_tables(thd);
}
DBUG_RETURN(test(ret));
}
/**
@} (End of group Event_Scheduler)
*/
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