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mariadb/sql/events.cc
Jon Olav Hauglid 7f0386545b Bug #44171 KILL ALTER EVENT can crash the server 
This assert could be triggered if ALTER EVENT failed to load the
event after altering it. Failing to load the event could for 
example happen because of KILL QUERY.

The assert tested that the result of a failed load_named_event()
was OP_LOAD_ERROR. However since load_named_event() returns bool,
this assert did not make any sense. This patch therefore removes
the assert, fixing the problem. The patch also removes 
enum_events_error_code since it was unused.

No test case added. The bug fix is trivial and this bug was
easily detected by RQG tests. Further, adding a MTR test case
for this bug would require adding sync points to make the
test case repeatable.
2010-08-26 12:01:43 +02:00

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/* Copyright (c) 2004, 2010, Oracle and/or its affiliates. All rights reserved.
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., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA */
#include "sql_priv.h"
#include "unireg.h"
#include "sql_parse.h" // check_access
#include "sql_base.h" // close_mysql_tables
#include "sql_show.h" // append_definer
#include "events.h"
#include "sql_db.h" // check_db_dir_existence
#include "sql_table.h" // write_bin_log
#include "tztime.h" // struct Time_zone
#include "sql_acl.h" // EVENT_ACL
#include "records.h" // init_read_record, end_read_record
#include "event_data_objects.h"
#include "event_db_repository.h"
#include "event_queue.h"
#include "event_scheduler.h"
#include "sp_head.h" // for Stored_program_creation_ctx
#include "set_var.h"
/**
@addtogroup Event_Scheduler
@{
*/
/*
TODO list :
- CREATE EVENT should not go into binary log! Does it now? The SQL statements
issued by the EVENT are replicated.
I have an idea how to solve the problem at failover. So the status field
will be ENUM('DISABLED', 'ENABLED', 'SLAVESIDE_DISABLED').
In this case when CREATE EVENT is replicated it should go into the binary
as SLAVESIDE_DISABLED if it is ENABLED, when it's created as DISABLEd it
should be replicated as disabled. If an event is ALTERed as DISABLED the
query should go untouched into the binary log, when ALTERed as enable then
it should go as SLAVESIDE_DISABLED. This is regarding the SQL interface.
TT routines however modify mysql.event internally and this does not go the
log so in this case queries has to be injected into the log...somehow... or
maybe a solution is RBR for this case, because the event may go only from
ENABLED to DISABLED status change and this is safe for replicating. As well
an event may be deleted which is also safe for RBR.
- Add logging to file
*/
/*
If the user (un)intentionally removes an event directly from mysql.event
the following sequence has to be used to be able to remove the in-memory
counterpart.
1. CREATE EVENT the_name ON SCHEDULE EVERY 1 SECOND DISABLE DO SELECT 1;
2. DROP EVENT the_name
In other words, the first one will create a row in mysql.event . In the
second step because there will be a line, disk based drop will pass and
the scheduler will remove the memory counterpart. The reason is that
in-memory queue does not check whether the event we try to drop from memory
is disabled. Disabled events are not kept in-memory because they are not
eligible for execution.
*/
Event_queue *Events::event_queue;
Event_scheduler *Events::scheduler;
Event_db_repository *Events::db_repository;
ulong Events::opt_event_scheduler= Events::EVENTS_OFF;
mysql_mutex_t Events::LOCK_event_metadata;
bool Events::check_system_tables_error= FALSE;
/*
Compares 2 LEX strings regarding case.
SYNOPSIS
sortcmp_lex_string()
s First LEX_STRING
t Second LEX_STRING
cs Charset
RETURN VALUE
-1 s < t
0 s == t
1 s > t
*/
int sortcmp_lex_string(LEX_STRING s, LEX_STRING t, CHARSET_INFO *cs)
{
return cs->coll->strnncollsp(cs, (uchar *) s.str,s.length,
(uchar *) t.str,t.length, 0);
}
/**
Push an error into the error stack if the system tables are
not up to date.
*/
bool Events::check_if_system_tables_error()
{
DBUG_ENTER("Events::check_if_system_tables_error");
if (check_system_tables_error)
{
my_error(ER_EVENTS_DB_ERROR, MYF(0));
DBUG_RETURN(TRUE);
}
DBUG_RETURN(FALSE);
}
/**
Reconstructs interval expression from interval type and expression
value that is in form of a value of the smalles entity:
For
YEAR_MONTH - expression is in months
DAY_MINUTE - expression is in minutes
SYNOPSIS
Events::reconstruct_interval_expression()
buf Preallocated String buffer to add the value to
interval The interval type (for instance YEAR_MONTH)
expression The value in the lowest entity
RETURN VALUE
0 OK
1 Error
*/
int
Events::reconstruct_interval_expression(String *buf, interval_type interval,
longlong expression)
{
ulonglong expr= expression;
char tmp_buff[128], *end;
bool close_quote= TRUE;
int multipl= 0;
char separator=':';
switch (interval) {
case INTERVAL_YEAR_MONTH:
multipl= 12;
separator= '-';
goto common_1_lev_code;
case INTERVAL_DAY_HOUR:
multipl= 24;
separator= ' ';
goto common_1_lev_code;
case INTERVAL_HOUR_MINUTE:
case INTERVAL_MINUTE_SECOND:
multipl= 60;
common_1_lev_code:
buf->append('\'');
end= longlong10_to_str(expression/multipl, tmp_buff, 10);
buf->append(tmp_buff, (uint) (end- tmp_buff));
expr= expr - (expr/multipl)*multipl;
break;
case INTERVAL_DAY_MINUTE:
{
ulonglong tmp_expr= expr;
tmp_expr/=(24*60);
buf->append('\'');
end= longlong10_to_str(tmp_expr, tmp_buff, 10);
buf->append(tmp_buff, (uint) (end- tmp_buff));// days
buf->append(' ');
tmp_expr= expr - tmp_expr*(24*60);//minutes left
end= longlong10_to_str(tmp_expr/60, tmp_buff, 10);
buf->append(tmp_buff, (uint) (end- tmp_buff));// hours
expr= tmp_expr - (tmp_expr/60)*60;
/* the code after the switch will finish */
}
break;
case INTERVAL_HOUR_SECOND:
{
ulonglong tmp_expr= expr;
buf->append('\'');
end= longlong10_to_str(tmp_expr/3600, tmp_buff, 10);
buf->append(tmp_buff, (uint) (end- tmp_buff));// hours
buf->append(':');
tmp_expr= tmp_expr - (tmp_expr/3600)*3600;
end= longlong10_to_str(tmp_expr/60, tmp_buff, 10);
buf->append(tmp_buff, (uint) (end- tmp_buff));// minutes
expr= tmp_expr - (tmp_expr/60)*60;
/* the code after the switch will finish */
}
break;
case INTERVAL_DAY_SECOND:
{
ulonglong tmp_expr= expr;
tmp_expr/=(24*3600);
buf->append('\'');
end= longlong10_to_str(tmp_expr, tmp_buff, 10);
buf->append(tmp_buff, (uint) (end- tmp_buff));// days
buf->append(' ');
tmp_expr= expr - tmp_expr*(24*3600);//seconds left
end= longlong10_to_str(tmp_expr/3600, tmp_buff, 10);
buf->append(tmp_buff, (uint) (end- tmp_buff));// hours
buf->append(':');
tmp_expr= tmp_expr - (tmp_expr/3600)*3600;
end= longlong10_to_str(tmp_expr/60, tmp_buff, 10);
buf->append(tmp_buff, (uint) (end- tmp_buff));// minutes
expr= tmp_expr - (tmp_expr/60)*60;
/* the code after the switch will finish */
}
break;
case INTERVAL_DAY_MICROSECOND:
case INTERVAL_HOUR_MICROSECOND:
case INTERVAL_MINUTE_MICROSECOND:
case INTERVAL_SECOND_MICROSECOND:
case INTERVAL_MICROSECOND:
my_error(ER_NOT_SUPPORTED_YET, MYF(0), "MICROSECOND");
return 1;
break;
case INTERVAL_QUARTER:
expr/= 3;
close_quote= FALSE;
break;
case INTERVAL_WEEK:
expr/= 7;
default:
close_quote= FALSE;
break;
}
if (close_quote)
buf->append(separator);
end= longlong10_to_str(expr, tmp_buff, 10);
buf->append(tmp_buff, (uint) (end- tmp_buff));
if (close_quote)
buf->append('\'');
return 0;
}
/**
Create a new query string for removing executable comments
for avoiding leak and keeping consistency of the execution
on master and slave.
@param[in] thd Thread handler
@param[in] buf Query string
@return
0 ok
1 error
*/
static int
create_query_string(THD *thd, String *buf)
{
/* Append the "CREATE" part of the query */
if (buf->append(STRING_WITH_LEN("CREATE ")))
return 1;
/* Append definer */
append_definer(thd, buf, &(thd->lex->definer->user), &(thd->lex->definer->host));
/* Append the left part of thd->query after "DEFINER" part */
if (buf->append(thd->lex->stmt_definition_begin,
thd->lex->stmt_definition_end -
thd->lex->stmt_definition_begin))
return 1;
return 0;
}
/**
Create a new event.
@param[in,out] thd THD
@param[in] parse_data Event's data from parsing stage
@param[in] if_not_exists Whether IF NOT EXISTS was
specified
In case there is an event with the same name (db) and
IF NOT EXISTS is specified, an warning is put into the stack.
@sa Events::drop_event for the notes about locking, pre-locking
and Events DDL.
@retval FALSE OK
@retval TRUE Error (reported)
*/
bool
Events::create_event(THD *thd, Event_parse_data *parse_data,
bool if_not_exists)
{
int ret;
bool save_binlog_row_based;
DBUG_ENTER("Events::create_event");
if (check_if_system_tables_error())
DBUG_RETURN(TRUE);
/*
Perform semantic checks outside of Event_db_repository:
once CREATE EVENT is supported in prepared statements, the
checks will be moved to PREPARE phase.
*/
if (parse_data->check_parse_data(thd))
DBUG_RETURN(TRUE);
/* At create, one of them must be set */
DBUG_ASSERT(parse_data->expression || parse_data->execute_at);
if (check_access(thd, EVENT_ACL, parse_data->dbname.str, NULL, NULL, 0, 0))
DBUG_RETURN(TRUE);
if (check_db_dir_existence(parse_data->dbname.str))
{
my_error(ER_BAD_DB_ERROR, MYF(0), parse_data->dbname.str);
DBUG_RETURN(TRUE);
}
if (parse_data->do_not_create)
DBUG_RETURN(FALSE);
/*
Turn off row binlogging of this statement and use statement-based
so that all supporting tables are updated for CREATE EVENT command.
*/
if ((save_binlog_row_based= thd->is_current_stmt_binlog_format_row()))
thd->clear_current_stmt_binlog_format_row();
mysql_mutex_lock(&LOCK_event_metadata);
/* On error conditions my_error() is called so no need to handle here */
if (!(ret= db_repository->create_event(thd, parse_data, if_not_exists)))
{
Event_queue_element *new_element;
bool dropped= 0;
if (!(new_element= new Event_queue_element()))
ret= TRUE; // OOM
else if ((ret= db_repository->load_named_event(thd, parse_data->dbname,
parse_data->name,
new_element)))
{
if (!db_repository->drop_event(thd, parse_data->dbname, parse_data->name,
TRUE))
dropped= 1;
delete new_element;
}
else
{
/* TODO: do not ignore the out parameter and a possible OOM error! */
bool created;
if (event_queue)
event_queue->create_event(thd, new_element, &created);
}
/*
binlog the create event unless it's been successfully dropped
*/
if (!dropped)
{
/* Binlog the create event. */
DBUG_ASSERT(thd->query() && thd->query_length());
String log_query;
if (create_query_string(thd, &log_query))
{
sql_print_error("Event Error: An error occurred while creating query string, "
"before writing it into binary log.");
ret= TRUE;
}
else
{
/* If the definer is not set or set to CURRENT_USER, the value of CURRENT_USER
will be written into the binary log as the definer for the SQL thread. */
ret= write_bin_log(thd, TRUE, log_query.c_ptr(), log_query.length());
}
}
}
mysql_mutex_unlock(&LOCK_event_metadata);
/* 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(ret);
}
/**
Alter an event.
@param[in,out] thd THD
@param[in] parse_data Event's data from parsing stage
@param[in] new_dbname A new schema name for the event. Set in the case of
ALTER EVENT RENAME, otherwise is NULL.
@param[in] new_name A new name for the event. Set in the case of
ALTER EVENT RENAME
Parameter 'et' contains data about dbname and event name.
Parameter 'new_name' is the new name of the event, if not null
this means that RENAME TO was specified in the query
@sa Events::drop_event for the locking notes.
@retval FALSE OK
@retval TRUE error (reported)
*/
bool
Events::update_event(THD *thd, Event_parse_data *parse_data,
LEX_STRING *new_dbname, LEX_STRING *new_name)
{
int ret;
bool save_binlog_row_based;
Event_queue_element *new_element;
DBUG_ENTER("Events::update_event");
if (check_if_system_tables_error())
DBUG_RETURN(TRUE);
if (parse_data->check_parse_data(thd) || parse_data->do_not_create)
DBUG_RETURN(TRUE);
if (check_access(thd, EVENT_ACL, parse_data->dbname.str, NULL, NULL, 0, 0))
DBUG_RETURN(TRUE);
if (new_dbname) /* It's a rename */
{
/* Check that the new and the old names differ. */
if ( !sortcmp_lex_string(parse_data->dbname, *new_dbname,
system_charset_info) &&
!sortcmp_lex_string(parse_data->name, *new_name,
system_charset_info))
{
my_error(ER_EVENT_SAME_NAME, MYF(0), parse_data->name.str);
DBUG_RETURN(TRUE);
}
/*
And the user has sufficient privileges to use the target database.
Do it before checking whether the database exists: we don't want
to tell the user that a database doesn't exist if they can not
access it.
*/
if (check_access(thd, EVENT_ACL, new_dbname->str, NULL, NULL, 0, 0))
DBUG_RETURN(TRUE);
/* Check that the target database exists */
if (check_db_dir_existence(new_dbname->str))
{
my_error(ER_BAD_DB_ERROR, MYF(0), new_dbname->str);
DBUG_RETURN(TRUE);
}
}
/*
Turn off row binlogging of this statement and use statement-based
so that all supporting tables are updated for UPDATE EVENT command.
*/
if ((save_binlog_row_based= thd->is_current_stmt_binlog_format_row()))
thd->clear_current_stmt_binlog_format_row();
mysql_mutex_lock(&LOCK_event_metadata);
/* On error conditions my_error() is called so no need to handle here */
if (!(ret= db_repository->update_event(thd, parse_data,
new_dbname, new_name)))
{
LEX_STRING dbname= new_dbname ? *new_dbname : parse_data->dbname;
LEX_STRING name= new_name ? *new_name : parse_data->name;
if (!(new_element= new Event_queue_element()))
ret= TRUE; // OOM
else if ((ret= db_repository->load_named_event(thd, dbname, name,
new_element)))
delete new_element;
else
{
/*
TODO: check if an update actually has inserted an entry
into the queue.
If not, and the element is ON COMPLETION NOT PRESERVE, delete
it right away.
*/
if (event_queue)
event_queue->update_event(thd, parse_data->dbname, parse_data->name,
new_element);
/* Binlog the alter event. */
DBUG_ASSERT(thd->query() && thd->query_length());
ret= write_bin_log(thd, TRUE, thd->query(), thd->query_length());
}
}
mysql_mutex_unlock(&LOCK_event_metadata);
/* 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(ret);
}
/**
Drops an event
@param[in,out] thd THD
@param[in] dbname Event's schema
@param[in] name Event's name
@param[in] if_exists When this is set and the event does not exist
a warning is pushed into the warning stack.
Otherwise the operation produces an error.
@note Similarly to DROP PROCEDURE, we do not allow DROP EVENT
under LOCK TABLES mode, unless table mysql.event is locked. To
ensure that, we do not reset & backup the open tables state in
this function - if in LOCK TABLES or pre-locking mode, this will
lead to an error 'Table mysql.event is not locked with LOCK
TABLES' unless it _is_ locked. In pre-locked mode there is
another barrier - DROP EVENT commits the current transaction,
and COMMIT/ROLLBACK is not allowed in stored functions and
triggers.
@retval FALSE OK
@retval TRUE Error (reported)
*/
bool
Events::drop_event(THD *thd, LEX_STRING dbname, LEX_STRING name, bool if_exists)
{
int ret;
bool save_binlog_row_based;
DBUG_ENTER("Events::drop_event");
if (check_if_system_tables_error())
DBUG_RETURN(TRUE);
if (check_access(thd, EVENT_ACL, dbname.str, NULL, NULL, 0, 0))
DBUG_RETURN(TRUE);
/*
Turn off row binlogging of this statement and use statement-based so
that all supporting tables are updated for DROP EVENT command.
*/
if ((save_binlog_row_based= thd->is_current_stmt_binlog_format_row()))
thd->clear_current_stmt_binlog_format_row();
mysql_mutex_lock(&LOCK_event_metadata);
/* On error conditions my_error() is called so no need to handle here */
if (!(ret= db_repository->drop_event(thd, dbname, name, if_exists)))
{
if (event_queue)
event_queue->drop_event(thd, dbname, name);
/* Binlog the drop event. */
DBUG_ASSERT(thd->query() && thd->query_length());
ret= write_bin_log(thd, TRUE, thd->query(), thd->query_length());
}
mysql_mutex_unlock(&LOCK_event_metadata);
/* 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(ret);
}
/**
Drops all events from a schema
@note We allow to drop all events in a schema even if the
scheduler is disabled. This is to not produce any warnings
in case of DROP DATABASE and a disabled scheduler.
@param[in,out] thd Thread
@param[in] db ASCIIZ schema name
*/
void
Events::drop_schema_events(THD *thd, char *db)
{
LEX_STRING const db_lex= { db, strlen(db) };
DBUG_ENTER("Events::drop_schema_events");
DBUG_PRINT("enter", ("dropping events from %s", db));
/*
sic: no check if the scheduler is disabled or system tables
are damaged, as intended.
*/
mysql_mutex_lock(&LOCK_event_metadata);
if (event_queue)
event_queue->drop_schema_events(thd, db_lex);
db_repository->drop_schema_events(thd, db_lex);
mysql_mutex_unlock(&LOCK_event_metadata);
DBUG_VOID_RETURN;
}
/**
A helper function to generate SHOW CREATE EVENT output from
a named event
*/
static bool
send_show_create_event(THD *thd, Event_timed *et, Protocol *protocol)
{
char show_str_buf[10 * STRING_BUFFER_USUAL_SIZE];
String show_str(show_str_buf, sizeof(show_str_buf), system_charset_info);
List<Item> field_list;
LEX_STRING sql_mode;
const String *tz_name;
DBUG_ENTER("send_show_create_event");
show_str.length(0);
if (et->get_create_event(thd, &show_str))
DBUG_RETURN(TRUE);
field_list.push_back(new Item_empty_string("Event", NAME_CHAR_LEN));
if (sql_mode_string_representation(thd, et->sql_mode, &sql_mode))
DBUG_RETURN(TRUE);
field_list.push_back(new Item_empty_string("sql_mode", (uint) sql_mode.length));
tz_name= et->time_zone->get_name();
field_list.push_back(new Item_empty_string("time_zone",
tz_name->length()));
field_list.push_back(new Item_empty_string("Create Event",
show_str.length()));
field_list.push_back(
new Item_empty_string("character_set_client", MY_CS_NAME_SIZE));
field_list.push_back(
new Item_empty_string("collation_connection", MY_CS_NAME_SIZE));
field_list.push_back(
new Item_empty_string("Database Collation", MY_CS_NAME_SIZE));
if (protocol->send_result_set_metadata(&field_list,
Protocol::SEND_NUM_ROWS | Protocol::SEND_EOF))
DBUG_RETURN(TRUE);
protocol->prepare_for_resend();
protocol->store(et->name.str, et->name.length, system_charset_info);
protocol->store(sql_mode.str, sql_mode.length, system_charset_info);
protocol->store(tz_name->ptr(), tz_name->length(), system_charset_info);
protocol->store(show_str.c_ptr(), show_str.length(),
et->creation_ctx->get_client_cs());
protocol->store(et->creation_ctx->get_client_cs()->csname,
strlen(et->creation_ctx->get_client_cs()->csname),
system_charset_info);
protocol->store(et->creation_ctx->get_connection_cl()->name,
strlen(et->creation_ctx->get_connection_cl()->name),
system_charset_info);
protocol->store(et->creation_ctx->get_db_cl()->name,
strlen(et->creation_ctx->get_db_cl()->name),
system_charset_info);
if (protocol->write())
DBUG_RETURN(TRUE);
my_eof(thd);
DBUG_RETURN(FALSE);
}
/**
Implement SHOW CREATE EVENT statement
thd Thread context
spn The name of the event (db, name)
@retval FALSE OK
@retval TRUE error (reported)
*/
bool
Events::show_create_event(THD *thd, LEX_STRING dbname, LEX_STRING name)
{
Event_timed et;
bool ret;
DBUG_ENTER("Events::show_create_event");
DBUG_PRINT("enter", ("name: %s@%s", dbname.str, name.str));
if (check_if_system_tables_error())
DBUG_RETURN(TRUE);
if (check_access(thd, EVENT_ACL, dbname.str, NULL, NULL, 0, 0))
DBUG_RETURN(TRUE);
/*
We would like to allow SHOW CREATE EVENT under LOCK TABLES and
in pre-locked mode. mysql.event table is marked as a system table.
This flag reduces the set of its participation scenarios in LOCK TABLES
operation, and therefore an out-of-bound open of this table
for reading like the one below (sic, only for reading) is
more or less deadlock-free. For additional information about when a
deadlock can occur please refer to the description of 'system table'
flag.
*/
ret= db_repository->load_named_event(thd, dbname, name, &et);
if (!ret)
ret= send_show_create_event(thd, &et, thd->protocol);
DBUG_RETURN(ret);
}
/**
Check access rights and fill INFORMATION_SCHEMA.events table.
@param[in,out] thd Thread context
@param[in] tables The temporary table to fill.
In MySQL INFORMATION_SCHEMA tables are temporary tables that are
created and filled on demand. In this function, we fill
INFORMATION_SCHEMA.events. It is a callback for I_S module, invoked from
sql_show.cc
@return Has to be integer, as such is the requirement of the I_S API
@retval 0 success
@retval 1 an error, pushed into the error stack
*/
int
Events::fill_schema_events(THD *thd, TABLE_LIST *tables, COND * /* cond */)
{
char *db= NULL;
int ret;
DBUG_ENTER("Events::fill_schema_events");
if (check_if_system_tables_error())
DBUG_RETURN(1);
/*
If it's SHOW EVENTS then thd->lex->select_lex.db is guaranteed not to
be NULL. Let's do an assert anyway.
*/
if (thd->lex->sql_command == SQLCOM_SHOW_EVENTS)
{
DBUG_ASSERT(thd->lex->select_lex.db);
if (!is_infoschema_db(thd->lex->select_lex.db) && // There is no events in I_S
check_access(thd, EVENT_ACL, thd->lex->select_lex.db,
NULL, NULL, 0, 0))
DBUG_RETURN(1);
db= thd->lex->select_lex.db;
}
ret= db_repository->fill_schema_events(thd, tables, db);
DBUG_RETURN(ret);
}
/**
Initializes the scheduler's structures.
@param opt_noacl_or_bootstrap
TRUE if there is --skip-grant-tables or --bootstrap
option. In that case we disable the event scheduler.
@note This function is not synchronized.
@retval FALSE Perhaps there was an error, and the event scheduler
is disabled. But the error is not fatal and the
server start up can continue.
@retval TRUE Fatal error. Startup must terminate (call unireg_abort()).
*/
bool
Events::init(my_bool opt_noacl_or_bootstrap)
{
THD *thd;
bool res= FALSE;
DBUG_ENTER("Events::init");
/* We need a temporary THD during boot */
if (!(thd= new THD()))
{
res= TRUE;
goto end;
}
/*
The thread stack does not start from this function but we cannot
guess the real value. So better some value that doesn't assert than
no value.
*/
thd->thread_stack= (char*) &thd;
thd->store_globals();
/*
We will need Event_db_repository anyway, even if the scheduler is
disabled - to perform events DDL.
*/
if (!(db_repository= new Event_db_repository))
{
res= TRUE; /* fatal error: request unireg_abort */
goto end;
}
/*
Since we allow event DDL even if the scheduler is disabled,
check the system tables, as we might need them.
If run with --skip-grant-tables or --bootstrap, don't try to do the
check of system tables and don't complain: in these modes the tables
are most likely not there and we're going to disable the event
scheduler anyway.
*/
if (opt_noacl_or_bootstrap || Event_db_repository::check_system_tables(thd))
{
if (! opt_noacl_or_bootstrap)
{
sql_print_error("Event Scheduler: An error occurred when initializing "
"system tables. Disabling the Event Scheduler.");
check_system_tables_error= TRUE;
}
/* Disable the scheduler since the system tables are not up to date */
opt_event_scheduler= EVENTS_DISABLED;
goto end;
}
/*
Was disabled explicitly from the command line, or because we're running
with --skip-grant-tables, or --bootstrap, or because we have no system
tables.
*/
if (opt_event_scheduler == Events::EVENTS_DISABLED)
goto end;
DBUG_ASSERT(opt_event_scheduler == Events::EVENTS_ON ||
opt_event_scheduler == Events::EVENTS_OFF);
if (!(event_queue= new Event_queue) ||
!(scheduler= new Event_scheduler(event_queue)))
{
res= TRUE; /* fatal error: request unireg_abort */
goto end;
}
if (event_queue->init_queue(thd) || load_events_from_db(thd) ||
(opt_event_scheduler == EVENTS_ON && scheduler->start()))
{
sql_print_error("Event Scheduler: Error while loading from disk.");
res= TRUE; /* fatal error: request unireg_abort */
goto end;
}
Event_worker_thread::init(db_repository);
end:
if (res)
{
delete db_repository;
delete event_queue;
delete scheduler;
}
delete thd;
/* Remember that we don't have a THD */
my_pthread_setspecific_ptr(THR_THD, NULL);
DBUG_RETURN(res);
}
/*
Cleans up scheduler's resources. Called at server shutdown.
SYNOPSIS
Events::deinit()
NOTES
This function is not synchronized.
*/
void
Events::deinit()
{
DBUG_ENTER("Events::deinit");
if (opt_event_scheduler != EVENTS_DISABLED)
{
delete scheduler;
scheduler= NULL; /* safety */
delete event_queue;
event_queue= NULL; /* safety */
}
delete db_repository;
db_repository= NULL; /* safety */
DBUG_VOID_RETURN;
}
#ifdef HAVE_PSI_INTERFACE
PSI_mutex_key key_LOCK_event_metadata, key_LOCK_event_queue,
key_event_scheduler_LOCK_scheduler_state;
static PSI_mutex_info all_events_mutexes[]=
{
{ &key_LOCK_event_metadata, "LOCK_event_metadata", PSI_FLAG_GLOBAL},
{ &key_LOCK_event_queue, "LOCK_event_queue", PSI_FLAG_GLOBAL},
{ &key_event_scheduler_LOCK_scheduler_state, "Event_scheduler::LOCK_scheduler_state", PSI_FLAG_GLOBAL}
};
PSI_cond_key key_event_scheduler_COND_state, key_COND_queue_state;
static PSI_cond_info all_events_conds[]=
{
{ &key_event_scheduler_COND_state, "Event_scheduler::COND_state", PSI_FLAG_GLOBAL},
{ &key_COND_queue_state, "COND_queue_state", PSI_FLAG_GLOBAL},
};
PSI_thread_key key_thread_event_scheduler, key_thread_event_worker;
static PSI_thread_info all_events_threads[]=
{
{ &key_thread_event_scheduler, "event_scheduler", PSI_FLAG_GLOBAL},
{ &key_thread_event_worker, "event_worker", 0}
};
static void init_events_psi_keys(void)
{
const char* category= "sql";
int count;
if (PSI_server == NULL)
return;
count= array_elements(all_events_mutexes);
PSI_server->register_mutex(category, all_events_mutexes, count);
count= array_elements(all_events_conds);
PSI_server->register_cond(category, all_events_conds, count);
count= array_elements(all_events_threads);
PSI_server->register_thread(category, all_events_threads, count);
}
#endif /* HAVE_PSI_INTERFACE */
/**
Inits Events mutexes
SYNOPSIS
Events::init_mutexes()
thd Thread
*/
void
Events::init_mutexes()
{
#ifdef HAVE_PSI_INTERFACE
init_events_psi_keys();
#endif
mysql_mutex_init(key_LOCK_event_metadata,
&LOCK_event_metadata, MY_MUTEX_INIT_FAST);
}
/*
Destroys Events mutexes
SYNOPSIS
Events::destroy_mutexes()
*/
void
Events::destroy_mutexes()
{
mysql_mutex_destroy(&LOCK_event_metadata);
}
/*
Dumps the internal status of the scheduler and the memory cache
into a table with two columns - Name & Value. Different properties
which could be useful for debugging for instance deadlocks are
returned.
SYNOPSIS
Events::dump_internal_status()
*/
void
Events::dump_internal_status()
{
DBUG_ENTER("Events::dump_internal_status");
puts("\n\n\nEvents status:");
puts("LLA = Last Locked At LUA = Last Unlocked At");
puts("WOC = Waiting On Condition DL = Data Locked");
/*
opt_event_scheduler should only be accessed while
holding LOCK_global_system_variables.
*/
mysql_mutex_lock(&LOCK_global_system_variables);
if (opt_event_scheduler == EVENTS_DISABLED)
puts("The Event Scheduler is disabled");
else
{
scheduler->dump_internal_status();
event_queue->dump_internal_status();
}
mysql_mutex_unlock(&LOCK_global_system_variables);
DBUG_VOID_RETURN;
}
bool Events::start()
{
return scheduler->start();
}
bool Events::stop()
{
return scheduler->stop();
}
/**
Loads all ENABLED events from mysql.event into a prioritized
queue.
This function is called during the server start up. It reads
every event, computes the next execution time, and if the event
needs execution, adds it to a prioritized queue. Otherwise, if
ON COMPLETION DROP is specified, the event is automatically
removed from the table.
@param[in,out] thd Thread context. Used for memory allocation in some cases.
@retval FALSE success
@retval TRUE error, the load is aborted
@note Reports the error to the console
*/
bool
Events::load_events_from_db(THD *thd)
{
TABLE *table;
READ_RECORD read_record_info;
bool ret= TRUE;
uint count= 0;
ulong saved_master_access;
DBUG_ENTER("Events::load_events_from_db");
DBUG_PRINT("enter", ("thd: 0x%lx", (long) thd));
/*
NOTE: even if we run in read-only mode, we should be able to lock the
mysql.event table for writing. In order to achieve this, we should call
mysql_lock_tables() under the super user.
*/
saved_master_access= thd->security_ctx->master_access;
thd->security_ctx->master_access |= SUPER_ACL;
ret= db_repository->open_event_table(thd, TL_WRITE, &table);
thd->security_ctx->master_access= saved_master_access;
if (ret)
{
sql_print_error("Event Scheduler: Failed to open table mysql.event");
DBUG_RETURN(TRUE);
}
init_read_record(&read_record_info, thd, table, NULL, 0, 1, FALSE);
while (!(read_record_info.read_record(&read_record_info)))
{
Event_queue_element *et;
bool created;
bool drop_on_completion;
if (!(et= new Event_queue_element))
goto end;
DBUG_PRINT("info", ("Loading event from row."));
if (et->load_from_row(thd, table))
{
sql_print_error("Event Scheduler: "
"Error while loading events from mysql.event. "
"The table probably contains bad data or is corrupted");
delete et;
goto end;
}
drop_on_completion= (et->on_completion ==
Event_parse_data::ON_COMPLETION_DROP);
if (event_queue->create_event(thd, et, &created))
{
/* Out of memory */
delete et;
goto end;
}
if (created)
count++;
else if (drop_on_completion)
{
/*
If not created, a stale event - drop if immediately if
ON COMPLETION NOT PRESERVE.
XXX: This won't be replicated, thus the drop won't appear in
in the slave. When the slave is restarted it will drop events.
However, as the slave will be "out of sync", it might happen that
an event created on the master, after master restart, won't be
replicated to the slave correctly, as the create will fail there.
*/
int rc= table->file->ha_delete_row(table->record[0]);
if (rc)
{
table->file->print_error(rc, MYF(0));
goto end;
}
}
}
sql_print_information("Event Scheduler: Loaded %d event%s",
count, (count == 1) ? "" : "s");
ret= FALSE;
end:
end_read_record(&read_record_info);
close_mysql_tables(thd);
DBUG_RETURN(ret);
}
/**
@} (End of group Event_Scheduler)
*/
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