/
events.cc
1328 lines (1106 loc) · 38.8 KB
/
events.cc
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/*
Copyright (c) 2005, 2013, Oracle and/or its affiliates.
Copyright (c) 2017, 2020, MariaDB Corporation.
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 02110-1335 USA */
#include "mariadb.h"
#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"
#include "lock.h" // lock_object_name
#include "mysql/psi/mysql_sp.h"
#include "wsrep_mysqld.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;
ulong Events::startup_state= Events::EVENTS_OFF;
ulong Events::inited;
/*
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(const LEX_CSTRING *s, const LEX_CSTRING *t,
const CHARSET_INFO *cs)
{
return cs->strnncollsp(s->str, s->length,
t->str, t->length);
}
/**
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 (opt_noacl)
{
my_error(ER_OPTION_PREVENTS_STATEMENT, MYF(0),
opt_bootstrap ? "--bootstrap" : "--skip-grant-tables");
DBUG_RETURN(TRUE);
}
else if (!inited)
{
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 smallest 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;
case INTERVAL_QUARTER:
expr/= 3;
close_quote= FALSE;
break;
case INTERVAL_WEEK:
expr/= 7;
close_quote= FALSE;
break;
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)
{
buf->length(0);
/* Append the "CREATE" part of the query */
if (thd->lex->create_info.or_replace())
{
if (buf->append(STRING_WITH_LEN("CREATE OR REPLACE ")))
return 1;
}
else 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
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 ret;
bool event_already_exists;
enum_binlog_format save_binlog_format;
DBUG_ENTER("Events::create_event");
if (unlikely(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);
WSREP_TO_ISOLATION_BEGIN(WSREP_MYSQL_DB, NULL, NULL);
if (lock_object_name(thd, MDL_key::EVENT,
parse_data->dbname.str, parse_data->name.str))
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.
*/
save_binlog_format= thd->set_current_stmt_binlog_format_stmt();
if (thd->lex->create_info.or_replace() && event_queue)
event_queue->drop_event(thd, &parse_data->dbname, &parse_data->name);
/* On error conditions my_error() is called so no need to handle here */
if (!(ret= db_repository->create_event(thd, parse_data,
&event_already_exists)))
{
Event_queue_element *new_element;
bool dropped= 0;
if (!event_already_exists)
{
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());
char buffer[1024];
String log_query(buffer, sizeof(buffer), &my_charset_bin);
if (create_query_string(thd, &log_query))
ret= true; // EE_OUTOFMEMORY set by my_malloc()
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.ptr(), log_query.length());
}
}
}
thd->restore_stmt_binlog_format(save_binlog_format);
if (!ret && Events::opt_event_scheduler == Events::EVENTS_OFF)
{
push_warning(thd, Sql_condition::WARN_LEVEL_WARN, ER_UNKNOWN_ERROR,
"Event scheduler is switched off, use SET GLOBAL event_scheduler=ON to enable it.");
}
DBUG_RETURN(ret);
#ifdef WITH_WSREP
wsrep_error_label:
DBUG_RETURN(true);
#endif
}
/**
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_CSTRING *new_dbname, LEX_CSTRING *new_name)
{
int ret;
enum_binlog_format save_binlog_format;
Event_queue_element *new_element;
DBUG_ENTER("Events::update_event");
if (unlikely(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);
WSREP_TO_ISOLATION_BEGIN(WSREP_MYSQL_DB, NULL, NULL);
if (lock_object_name(thd, MDL_key::EVENT,
parse_data->dbname.str, parse_data->name.str))
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 (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));
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);
/*
Acquire mdl exclusive lock on target database name.
*/
if (lock_object_name(thd, MDL_key::EVENT,
new_dbname->str, new_name->str))
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.
*/
save_binlog_format= thd->set_current_stmt_binlog_format_stmt();
/* 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_CSTRING dbname= new_dbname ? *new_dbname : parse_data->dbname;
LEX_CSTRING 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());
}
}
thd->restore_stmt_binlog_format(save_binlog_format);
DBUG_RETURN(ret);
#ifdef WITH_WSREP
wsrep_error_label:
DBUG_RETURN(true);
#endif
}
/**
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, const LEX_CSTRING *dbname,
const LEX_CSTRING *name, bool if_exists)
{
int ret;
enum_binlog_format save_binlog_format;
DBUG_ENTER("Events::drop_event");
if (unlikely(check_if_system_tables_error()))
DBUG_RETURN(TRUE);
if (check_access(thd, EVENT_ACL, dbname->str, NULL, NULL, 0, 0))
DBUG_RETURN(TRUE);
WSREP_TO_ISOLATION_BEGIN(WSREP_MYSQL_DB, NULL, NULL);
/*
Turn off row binlogging of this statement and use statement-based so
that all supporting tables are updated for DROP EVENT command.
*/
save_binlog_format= thd->set_current_stmt_binlog_format_stmt();
if (lock_object_name(thd, MDL_key::EVENT,
dbname->str, name->str))
DBUG_RETURN(TRUE);
/* 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());
/* Drop statistics for this stored program from performance schema. */
MYSQL_DROP_SP(SP_TYPE_EVENT,
dbname->str, static_cast<uint>(dbname->length), name->str, static_cast<uint>(name->length));
}
thd->restore_stmt_binlog_format(save_binlog_format);
DBUG_RETURN(ret);
#ifdef WITH_WSREP
wsrep_error_label:
DBUG_RETURN(true);
#endif
}
/**
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, const char *db)
{
const LEX_CSTRING db_lex= { db, strlen(db) };
DBUG_ENTER("Events::drop_schema_events");
DBUG_PRINT("enter", ("dropping events from %s", db));
DBUG_SLOW_ASSERT(ok_for_lower_case_names(db));
/*
Sic: no check if the scheduler is disabled or system tables
are damaged, as intended.
*/
if (event_queue)
event_queue->drop_schema_events(thd, &db_lex);
if (db_repository)
db_repository->drop_schema_events(thd, &db_lex);
else
{
if ((db_repository= new Event_db_repository))
{
db_repository->drop_schema_events(thd, &db_lex);
delete db_repository;
db_repository= 0;
}
}
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_CSTRING sql_mode;
const String *tz_name;
MEM_ROOT *mem_root= thd->mem_root;
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 (mem_root)
Item_empty_string(thd, "Event", NAME_CHAR_LEN),
mem_root);
if (sql_mode_string_representation(thd, et->sql_mode, &sql_mode))
DBUG_RETURN(TRUE);
field_list.push_back(new (mem_root)
Item_empty_string(thd, "sql_mode",
(uint) sql_mode.length), mem_root);
tz_name= et->time_zone->get_name();
field_list.push_back(new (mem_root)
Item_empty_string(thd, "time_zone", tz_name->length()),
mem_root);
field_list.push_back(new (mem_root)
Item_empty_string(thd, "Create Event",
show_str.length()), mem_root);
field_list.push_back(new (mem_root)
Item_empty_string(thd, "character_set_client",
MY_CS_CHARACTER_SET_NAME_SIZE),
mem_root);
field_list.push_back(new (mem_root)
Item_empty_string(thd, "collation_connection",
MY_CS_COLLATION_NAME_SIZE), mem_root);
field_list.push_back(new (mem_root)
Item_empty_string(thd, "Database Collation",
MY_CS_COLLATION_NAME_SIZE), mem_root);
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.ptr(), show_str.length(),
et->creation_ctx->get_client_cs());
protocol->store(&et->creation_ctx->get_client_cs()->cs_name,
system_charset_info);
protocol->store(&et->creation_ctx->get_connection_cl()->coll_name,
system_charset_info);
protocol->store(&et->creation_ctx->get_db_cl()->coll_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, const LEX_CSTRING *dbname,
const LEX_CSTRING *name)
{
Event_timed et;
bool ret;
DBUG_ENTER("Events::show_create_event");
DBUG_PRINT("enter", ("name: %s@%s", dbname->str, name->str));
if (unlikely(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 */)
{
const char *db= NULL;
int ret;
char db_tmp[SAFE_NAME_LEN];
DBUG_ENTER("Events::fill_schema_events");
/*
If we didn't start events because of --skip-grant-tables, return an
empty set
*/
if (opt_noacl)
DBUG_RETURN(0);
if (unlikely(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)
{
LEX_CSTRING *lexdb= &thd->lex->first_select_lex()->db;
DBUG_ASSERT(lexdb);
if (!is_infoschema_db(lexdb) && !is_perfschema_db(lexdb) &&
check_access(thd, EVENT_ACL, lexdb->str, NULL, NULL, 0, 0))
DBUG_RETURN(1);
db= normalize_db_name(lexdb->str, db_tmp, sizeof(db_tmp));
}
ret= db_repository->fill_schema_events(thd, tables, db);
DBUG_RETURN(ret);
}
/**
Initializes the scheduler's structures.
@param THD or null (if called by init)
@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(THD *thd, bool opt_noacl_or_bootstrap)
{
int err_no;
bool res= FALSE;
bool had_thd= thd != 0;
DBUG_ENTER("Events::init");
DBUG_ASSERT(inited == 0);
/*
Was disabled explicitly from the command line
*/
if (opt_event_scheduler == Events::EVENTS_DISABLED || opt_bootstrap)
DBUG_RETURN(FALSE);
if (opt_noacl_or_bootstrap)
{
if (opt_event_scheduler == Events::EVENTS_ON)
sql_print_error("Event Scheduler will not function when starting with %s",
opt_bootstrap ? "--bootstrap" : "--skip-grant-tables");
opt_event_scheduler= EVENTS_DISABLED;
DBUG_RETURN(FALSE);
}
/* We need a temporary THD during boot */
if (!thd)
{
if (!(thd= new THD(0)))
{
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();
thd->set_query_inner((char*) STRING_WITH_LEN("intern:Events::init"),
default_charset_info);
/*
Set current time for the thread that handles events.
Current time is stored in data member start_time of THD class.
Subsequently, this value is used to check whether event was expired
when make loading events from storage. Check for event expiration time
is done at Event_queue_element::compute_next_execution_time() where
event's status set to Event_parse_data::DISABLED and dropped flag set
to true if event was expired.
*/
thd->set_time();
}
/*
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 off,
check the system tables, as we might need them.
If run with --skip-grant-tables or --bootstrap, we have already
disabled the event scheduler anyway.
*/
if (Event_db_repository::check_system_tables(thd))
{
delete db_repository;
db_repository= 0;
my_message(ER_STARTUP,
"Event Scheduler: An error occurred when initializing "
"system tables. Disabling the Event Scheduler.",
MYF(ME_ERROR_LOG));
/* Disable the scheduler since the system tables are not up to date */
opt_event_scheduler= EVENTS_OFF;
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(&err_no)))
{
my_message_sql(ER_STARTUP,
"Event Scheduler: Error while loading from mysql.event table.",
MYF(ME_ERROR_LOG));
res= TRUE; /* fatal error: request unireg_abort */
goto end;
}
Event_worker_thread::init(db_repository);
inited= 1;
end:
if (res)
deinit();
if (!had_thd)
delete thd;
DBUG_RETURN(res);
}
/*
Cleans up scheduler's resources. Called at server shutdown.
SYNOPSIS
Events::deinit()
NOTES
This function is not synchronized.
*/
void