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Extract reload_acl_and_cache() and flush_tables_with_read_lock()

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into an own implementation file.
This commit is contained in:
Konstantin Osipov
2010-08-13 13:51:48 +04:00
parent 7c3de33a4f
commit 8ce6e98aa3
12 changed files with 512 additions and 449 deletions
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407
sql/sql_parse.cc
View File

@@ -50,6 +50,7 @@
// mysql_backup_table,
// mysql_restore_table
#include "sql_truncate.h" // mysql_truncate_table
#include "sql_reload.h" // reload_acl_and_cache
#include "sql_connect.h" // check_user,
// decrease_user_connections,
// thd_init_client_charset, check_mqh,
@@ -1695,153 +1696,6 @@ int prepare_schema_table(THD *thd, LEX *lex, Table_ident *table_ident,
}
/**
Implementation of FLUSH TABLES <table_list> WITH READ LOCK.
In brief: take exclusive locks, expel tables from the table
cache, reopen the tables, enter the 'LOCKED TABLES' mode,
downgrade the locks.
Note: the function is written to be called from
mysql_execute_command(), it is not reusable in arbitrary
execution context.
Required privileges
-------------------
Since the statement implicitly enters LOCK TABLES mode,
it requires LOCK TABLES privilege on every table.
But since the rest of FLUSH commands require
the global RELOAD_ACL, it also requires RELOAD_ACL.
Compatibility with the global read lock
---------------------------------------
We don't wait for the GRL, since neither the
5.1 combination that this new statement is intended to
replace (LOCK TABLE <list> WRITE; FLUSH TABLES;),
nor FLUSH TABLES WITH READ LOCK do.
@todo: this is not implemented, Dmitry disagrees.
Currently we wait for GRL in another connection,
but are compatible with a GRL in our own connection.
Behaviour under LOCK TABLES
---------------------------
Bail out: i.e. don't perform an implicit UNLOCK TABLES.
This is not consistent with LOCK TABLES statement, but is
in line with behaviour of FLUSH TABLES WITH READ LOCK, and we
try to not introduce any new statements with implicit
semantics.
Compatibility with parallel updates
-----------------------------------
As a result, we will wait for all open transactions
against the tables to complete. After the lock downgrade,
new transactions will be able to read the tables, but not
write to them.
Differences from FLUSH TABLES <list>
-------------------------------------
- you can't flush WITH READ LOCK a non-existent table
- you can't flush WITH READ LOCK under LOCK TABLES
- currently incompatible with the GRL (@todo: fix)
Effect on views and temporary tables.
------------------------------------
You can only apply this command to existing base tables.
If a view with such name exists, ER_WRONG_OBJECT is returned.
If a temporary table with such name exists, it's ignored:
if there is a base table, it's used, otherwise ER_NO_SUCH_TABLE
is returned.
Implicit commit
---------------
This statement causes an implicit commit before and
after it.
HANDLER SQL
-----------
If this connection has HANDLERs open against
some of the tables being FLUSHed, these handlers
are implicitly flushed (lose their position).
*/
static bool flush_tables_with_read_lock(THD *thd, TABLE_LIST *all_tables)
{
Lock_tables_prelocking_strategy lock_tables_prelocking_strategy;
TABLE_LIST *table_list;
MDL_request_list mdl_requests;
/*
This is called from SQLCOM_FLUSH, the transaction has
been committed implicitly.
*/
/* RELOAD_ACL is checked by the caller. Check table-level privileges. */
if (check_table_access(thd, LOCK_TABLES_ACL | SELECT_ACL, all_tables,
FALSE, UINT_MAX, FALSE))
goto error;
if (thd->locked_tables_mode)
{
my_error(ER_LOCK_OR_ACTIVE_TRANSACTION, MYF(0));
goto error;
}
/*
Acquire SNW locks on tables to be flushed. We can't use
lock_table_names() here as this call will also acquire global IX
and database-scope IX locks on the tables, and this will make
this statement incompatible with FLUSH TABLES WITH READ LOCK.
*/
for (table_list= all_tables; table_list;
table_list= table_list->next_global)
mdl_requests.push_front(&table_list->mdl_request);
if (thd->mdl_context.acquire_locks(&mdl_requests,
thd->variables.lock_wait_timeout))
goto error;
DEBUG_SYNC(thd,"flush_tables_with_read_lock_after_acquire_locks");
for (table_list= all_tables; table_list;
table_list= table_list->next_global)
{
/* Request removal of table from cache. */
tdc_remove_table(thd, TDC_RT_REMOVE_UNUSED,
table_list->db,
table_list->table_name, FALSE);
/* Skip views and temporary tables. */
table_list->required_type= FRMTYPE_TABLE; /* Don't try to flush views. */
table_list->open_type= OT_BASE_ONLY; /* Ignore temporary tables. */
}
/*
Before opening and locking tables the below call also waits
for old shares to go away, so the fact that we don't pass
MYSQL_LOCK_IGNORE_FLUSH flag to it is important.
*/
if (open_and_lock_tables(thd, all_tables, FALSE,
MYSQL_OPEN_HAS_MDL_LOCK,
&lock_tables_prelocking_strategy) ||
thd->locked_tables_list.init_locked_tables(thd))
{
goto error;
}
thd->variables.option_bits|= OPTION_TABLE_LOCK;
/*
We don't downgrade MDL_SHARED_NO_WRITE here as the intended
post effect of this call is identical to LOCK TABLES <...> READ,
and we didn't use thd->in_lock_talbes and
thd->sql_command= SQLCOM_LOCK_TABLES hacks to enter the LTM.
*/
return FALSE;
error:
return TRUE;
}
/**
Read query from packet and store in thd->query.
Used in COM_QUERY and COM_STMT_PREPARE.
@@ -3972,6 +3826,10 @@ end_with_restore_list:
if (first_table && lex->type & REFRESH_READ_LOCK)
{
/* Check table-level privileges. */
if (check_table_access(thd, LOCK_TABLES_ACL | SELECT_ACL, all_tables,
FALSE, UINT_MAX, FALSE))
goto error;
if (flush_tables_with_read_lock(thd, all_tables))
goto error;
my_ok(thd);
@@ -6704,261 +6562,6 @@ void add_join_natural(TABLE_LIST *a, TABLE_LIST *b, List<String> *using_fields,
}
/**
Reload/resets privileges and the different caches.
@param thd Thread handler (can be NULL!)
@param options What should be reset/reloaded (tables, privileges, slave...)
@param tables Tables to flush (if any)
@param write_to_binlog True if we can write to the binlog.
@note Depending on 'options', it may be very bad to write the
query to the binlog (e.g. FLUSH SLAVE); this is a
pointer where reload_acl_and_cache() will put 0 if
it thinks we really should not write to the binlog.
Otherwise it will put 1.
@return Error status code
@retval 0 Ok
@retval !=0 Error; thd->killed is set or thd->is_error() is true
*/
bool reload_acl_and_cache(THD *thd, ulong options, TABLE_LIST *tables,
bool *write_to_binlog)
{
bool result=0;
select_errors=0; /* Write if more errors */
bool tmp_write_to_binlog= 1;
DBUG_ASSERT(!thd || !thd->in_sub_stmt);
#ifndef NO_EMBEDDED_ACCESS_CHECKS
if (options & REFRESH_GRANT)
{
THD *tmp_thd= 0;
/*
If reload_acl_and_cache() is called from SIGHUP handler we have to
allocate temporary THD for execution of acl_reload()/grant_reload().
*/
if (!thd && (thd= (tmp_thd= new THD)))
{
thd->thread_stack= (char*) &tmp_thd;
thd->store_globals();
}
if (thd)
{
bool reload_acl_failed= acl_reload(thd);
bool reload_grants_failed= grant_reload(thd);
bool reload_servers_failed= servers_reload(thd);
if (reload_acl_failed || reload_grants_failed || reload_servers_failed)
{
result= 1;
/*
When an error is returned, my_message may have not been called and
the client will hang waiting for a response.
*/
my_error(ER_UNKNOWN_ERROR, MYF(0), "FLUSH PRIVILEGES failed");
}
}
if (tmp_thd)
{
delete tmp_thd;
/* Remember that we don't have a THD */
my_pthread_setspecific_ptr(THR_THD, 0);
thd= 0;
}
reset_mqh((LEX_USER *)NULL, TRUE);
}
#endif
if (options & REFRESH_LOG)
{
/*
Flush the normal query log, the update log, the binary log,
the slow query log, the relay log (if it exists) and the log
tables.
*/
options|= REFRESH_BINARY_LOG;
options|= REFRESH_RELAY_LOG;
options|= REFRESH_SLOW_LOG;
options|= REFRESH_GENERAL_LOG;
options|= REFRESH_ENGINE_LOG;
options|= REFRESH_ERROR_LOG;
}
if (options & REFRESH_ERROR_LOG)
if (flush_error_log())
result= 1;
if ((options & REFRESH_SLOW_LOG) && opt_slow_log)
logger.flush_slow_log();
if ((options & REFRESH_GENERAL_LOG) && opt_log)
logger.flush_general_log();
if (options & REFRESH_ENGINE_LOG)
if (ha_flush_logs(NULL))
result= 1;
if (options & REFRESH_BINARY_LOG)
{
/*
Writing this command to the binlog may result in infinite loops
when doing mysqlbinlog|mysql, and anyway it does not really make
sense to log it automatically (would cause more trouble to users
than it would help them)
*/
tmp_write_to_binlog= 0;
if (mysql_bin_log.is_open())
mysql_bin_log.rotate_and_purge(RP_FORCE_ROTATE);
}
if (options & REFRESH_RELAY_LOG)
{
#ifdef HAVE_REPLICATION
mysql_mutex_lock(&LOCK_active_mi);
rotate_relay_log(active_mi);
mysql_mutex_unlock(&LOCK_active_mi);
#endif
}
#ifdef HAVE_QUERY_CACHE
if (options & REFRESH_QUERY_CACHE_FREE)
{
query_cache.pack(); // FLUSH QUERY CACHE
options &= ~REFRESH_QUERY_CACHE; // Don't flush cache, just free memory
}
if (options & (REFRESH_TABLES | REFRESH_QUERY_CACHE))
{
query_cache.flush(); // RESET QUERY CACHE
}
#endif /*HAVE_QUERY_CACHE*/
DBUG_ASSERT(!thd || thd->locked_tables_mode ||
!thd->mdl_context.has_locks() ||
thd->handler_tables_hash.records ||
thd->global_read_lock.is_acquired());
/*
Note that if REFRESH_READ_LOCK bit is set then REFRESH_TABLES is set too
(see sql_yacc.yy)
*/
if (options & (REFRESH_TABLES | REFRESH_READ_LOCK))
{
if ((options & REFRESH_READ_LOCK) && thd)
{
/*
On the first hand we need write lock on the tables to be flushed,
on the other hand we must not try to aspire a global read lock
if we have a write locked table as this would lead to a deadlock
when trying to reopen (and re-lock) the table after the flush.
*/
if (thd->locked_tables_mode)
{
my_error(ER_LOCK_OR_ACTIVE_TRANSACTION, MYF(0));
return 1;
}
/*
Writing to the binlog could cause deadlocks, as we don't log
UNLOCK TABLES
*/
tmp_write_to_binlog= 0;
if (thd->global_read_lock.lock_global_read_lock(thd))
return 1; // Killed
if (close_cached_tables(thd, tables,
((options & REFRESH_FAST) ? FALSE : TRUE),
thd->variables.lock_wait_timeout))
result= 1;
if (thd->global_read_lock.make_global_read_lock_block_commit(thd)) // Killed
{
/* Don't leave things in a half-locked state */
thd->global_read_lock.unlock_global_read_lock(thd);
return 1;
}
}
else
{
if (thd && thd->locked_tables_mode)
{
/*
If we are under LOCK TABLES we should have a write
lock on tables which we are going to flush.
*/
if (tables)
{
for (TABLE_LIST *t= tables; t; t= t->next_local)
if (!find_table_for_mdl_upgrade(thd->open_tables, t->db,
t->table_name, FALSE))
return 1;
}
else
{
for (TABLE *tab= thd->open_tables; tab; tab= tab->next)
{
if (! tab->mdl_ticket->is_upgradable_or_exclusive())
{
my_error(ER_TABLE_NOT_LOCKED_FOR_WRITE, MYF(0),
tab->s->table_name.str);
return 1;
}
}
}
}
if (close_cached_tables(thd, tables,
((options & REFRESH_FAST) ? FALSE : TRUE),
(thd ? thd->variables.lock_wait_timeout :
LONG_TIMEOUT)))
result= 1;
}
my_dbopt_cleanup();
}
if (options & REFRESH_HOSTS)
hostname_cache_refresh();
if (thd && (options & REFRESH_STATUS))
refresh_status(thd);
if (options & REFRESH_THREADS)
flush_thread_cache();
#ifdef HAVE_REPLICATION
if (options & REFRESH_MASTER)
{
DBUG_ASSERT(thd);
tmp_write_to_binlog= 0;
if (reset_master(thd))
{
result=1;
}
}
#endif
#ifdef OPENSSL
if (options & REFRESH_DES_KEY_FILE)
{
if (des_key_file && load_des_key_file(des_key_file))
result= 1;
}
#endif
#ifdef HAVE_REPLICATION
if (options & REFRESH_SLAVE)
{
tmp_write_to_binlog= 0;
mysql_mutex_lock(&LOCK_active_mi);
if (reset_slave(thd, active_mi))
result=1;
mysql_mutex_unlock(&LOCK_active_mi);
}
#endif
if (options & REFRESH_USER_RESOURCES)
reset_mqh((LEX_USER *) NULL, 0); /* purecov: inspected */
*write_to_binlog= tmp_write_to_binlog;
/*
If the query was killed then this function must fail.
*/
return result || (thd ? thd->killed : 0);
}
/**
kill on thread.