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mariadb/sql/rpl_gtid.cc
Monty d1d472646d Change THD->transaction to a pointer to enable multiple transactions 
All changes (except one) is of type
thd->transaction.  -> thd->transaction->

thd->transaction points by default to 'thd->default_transaction'
This allows us to 'easily' have multiple active transactions for a
THD object, like when reading data from the mysql.proc table
2020-05-23 12:29:10 +03:00

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/* Copyright (c) 2013, Kristian Nielsen and MariaDB Services Ab.
Copyright (c) 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 */
/* Definitions for MariaDB global transaction ID (GTID). */
#include "mariadb.h"
#include "sql_priv.h"
#include "unireg.h"
#include "mariadb.h"
#include "sql_base.h"
#include "sql_parse.h"
#include "key.h"
#include "rpl_gtid.h"
#include "rpl_rli.h"
#include "slave.h"
#include "log_event.h"
const LEX_CSTRING rpl_gtid_slave_state_table_name=
{ STRING_WITH_LEN("gtid_slave_pos") };
void
rpl_slave_state::update_state_hash(uint64 sub_id, rpl_gtid *gtid, void *hton,
rpl_group_info *rgi)
{
int err;
/*
Add the gtid to the HASH in the replication slave state.
We must do this only _after_ commit, so that for parallel replication,
there will not be an attempt to delete the corresponding table row before
it is even committed.
*/
mysql_mutex_lock(&LOCK_slave_state);
err= update(gtid->domain_id, gtid->server_id, sub_id, gtid->seq_no, hton, rgi);
mysql_mutex_unlock(&LOCK_slave_state);
if (err)
{
sql_print_warning("Slave: Out of memory during slave state maintenance. "
"Some no longer necessary rows in table "
"mysql.%s may be left undeleted.",
rpl_gtid_slave_state_table_name.str);
/*
Such failure is not fatal. We will fail to delete the row for this
GTID, but it will do no harm and will be removed automatically on next
server restart.
*/
}
}
int
rpl_slave_state::record_and_update_gtid(THD *thd, rpl_group_info *rgi)
{
DBUG_ENTER("rpl_slave_state::record_and_update_gtid");
/*
Update the GTID position, if we have it and did not already update
it in a GTID transaction.
*/
if (rgi->gtid_pending)
{
uint64 sub_id= rgi->gtid_sub_id;
void *hton= NULL;
rgi->gtid_pending= false;
if (rgi->gtid_ignore_duplicate_state!=rpl_group_info::GTID_DUPLICATE_IGNORE)
{
if (record_gtid(thd, &rgi->current_gtid, sub_id, false, false, &hton))
DBUG_RETURN(1);
update_state_hash(sub_id, &rgi->current_gtid, hton, rgi);
}
rgi->gtid_ignore_duplicate_state= rpl_group_info::GTID_DUPLICATE_NULL;
}
DBUG_RETURN(0);
}
/*
Check GTID event execution when --gtid-ignore-duplicates.
The idea with --gtid-ignore-duplicates is that we allow multiple master
connections (in multi-source replication) to all receive the same GTIDs and
event groups. Only one instance of each is applied; we use the sequence
number in the GTID to decide whether a GTID has already been applied.
So if the seq_no of a GTID (or a higher sequence number) has already been
applied, then the event should be skipped. If not then the event should be
applied.
To avoid two master connections tring to apply the same event
simultaneously, only one is allowed to work in any given domain at any point
in time. The associated Relay_log_info object is called the owner of the
domain (and there can be multiple parallel worker threads working in that
domain for that Relay_log_info). Any other Relay_log_info/master connection
must wait for the domain to become free, or for their GTID to have been
applied, before being allowed to proceed.
Returns:
0 This GTID is already applied, it should be skipped.
1 The GTID is not yet applied; this rli is now the owner, and must apply
the event and release the domain afterwards.
-1 Error (out of memory to allocate a new element for the domain).
*/
int
rpl_slave_state::check_duplicate_gtid(rpl_gtid *gtid, rpl_group_info *rgi)
{
uint32 domain_id= gtid->domain_id;
uint64 seq_no= gtid->seq_no;
rpl_slave_state::element *elem;
int res;
bool did_enter_cond= false;
PSI_stage_info old_stage;
THD *UNINIT_VAR(thd);
Relay_log_info *rli= rgi->rli;
mysql_mutex_lock(&LOCK_slave_state);
if (!(elem= get_element(domain_id)))
{
my_error(ER_OUT_OF_RESOURCES, MYF(0));
res= -1;
goto err;
}
/*
Note that the elem pointer does not change once inserted in the hash. So
we can re-use the pointer without looking it up again in the hash after
each lock release and re-take.
*/
for (;;)
{
if (elem->highest_seq_no >= seq_no)
{
/* This sequence number is already applied, ignore it. */
res= 0;
rgi->gtid_ignore_duplicate_state= rpl_group_info::GTID_DUPLICATE_IGNORE;
break;
}
if (!elem->owner_rli)
{
/* The domain became free, grab it and apply the event. */
elem->owner_rli= rli;
elem->owner_count= 1;
rgi->gtid_ignore_duplicate_state= rpl_group_info::GTID_DUPLICATE_OWNER;
res= 1;
break;
}
if (elem->owner_rli == rli)
{
/* Already own this domain, increment reference count and apply event. */
++elem->owner_count;
rgi->gtid_ignore_duplicate_state= rpl_group_info::GTID_DUPLICATE_OWNER;
res= 1;
break;
}
thd= rgi->thd;
if (unlikely(thd->check_killed()))
{
res= -1;
break;
}
/*
Someone else is currently processing this GTID (or an earlier one).
Wait for them to complete (or fail), and then check again.
*/
if (!did_enter_cond)
{
thd->ENTER_COND(&elem->COND_gtid_ignore_duplicates, &LOCK_slave_state,
&stage_gtid_wait_other_connection, &old_stage);
did_enter_cond= true;
}
mysql_cond_wait(&elem->COND_gtid_ignore_duplicates,
&LOCK_slave_state);
}
err:
if (did_enter_cond)
thd->EXIT_COND(&old_stage);
else
mysql_mutex_unlock(&LOCK_slave_state);
return res;
}
void
rpl_slave_state::release_domain_owner(rpl_group_info *rgi)
{
element *elem= NULL;
mysql_mutex_lock(&LOCK_slave_state);
if (!(elem= get_element(rgi->current_gtid.domain_id)))
{
/*
We cannot really deal with error here, as we are already called in an
error handling case (transaction failure and rollback).
However, get_element() only fails if the element did not exist already
and could not be allocated due to out-of-memory - and if it did not
exist, then we would not get here in the first place.
*/
mysql_mutex_unlock(&LOCK_slave_state);
return;
}
if (rgi->gtid_ignore_duplicate_state == rpl_group_info::GTID_DUPLICATE_OWNER)
{
uint32 count= elem->owner_count;
DBUG_ASSERT(count > 0);
DBUG_ASSERT(elem->owner_rli == rgi->rli);
--count;
elem->owner_count= count;
if (count == 0)
{
elem->owner_rli= NULL;
mysql_cond_broadcast(&elem->COND_gtid_ignore_duplicates);
}
}
rgi->gtid_ignore_duplicate_state= rpl_group_info::GTID_DUPLICATE_NULL;
mysql_mutex_unlock(&LOCK_slave_state);
}
static void
rpl_slave_state_free_element(void *arg)
{
struct rpl_slave_state::element *elem= (struct rpl_slave_state::element *)arg;
mysql_cond_destroy(&elem->COND_wait_gtid);
mysql_cond_destroy(&elem->COND_gtid_ignore_duplicates);
my_free(elem);
}
rpl_slave_state::rpl_slave_state()
: pending_gtid_count(0), last_sub_id(0), gtid_pos_tables(0), loaded(false)
{
mysql_mutex_init(key_LOCK_slave_state, &LOCK_slave_state,
MY_MUTEX_INIT_SLOW);
my_hash_init(PSI_INSTRUMENT_ME, &hash, &my_charset_bin, 32, offsetof(element, domain_id),
sizeof(uint32), NULL, rpl_slave_state_free_element, HASH_UNIQUE);
my_init_dynamic_array(PSI_INSTRUMENT_ME, &gtid_sort_array, sizeof(rpl_gtid),
8, 8, MYF(0));
}
rpl_slave_state::~rpl_slave_state()
{
free_gtid_pos_tables(gtid_pos_tables.load(std::memory_order_relaxed));
truncate_hash();
my_hash_free(&hash);
delete_dynamic(&gtid_sort_array);
mysql_mutex_destroy(&LOCK_slave_state);
}
void
rpl_slave_state::truncate_hash()
{
uint32 i;
for (i= 0; i < hash.records; ++i)
{
element *e= (element *)my_hash_element(&hash, i);
list_element *l= e->list;
list_element *next;
while (l)
{
next= l->next;
my_free(l);
l= next;
}
/* The element itself is freed by the hash element free function. */
}
my_hash_reset(&hash);
}
int
rpl_slave_state::update(uint32 domain_id, uint32 server_id, uint64 sub_id,
uint64 seq_no, void *hton, rpl_group_info *rgi)
{
element *elem= NULL;
list_element *list_elem= NULL;
DBUG_ASSERT(hton || !loaded);
if (!(elem= get_element(domain_id)))
return 1;
if (seq_no > elem->highest_seq_no)
elem->highest_seq_no= seq_no;
if (elem->gtid_waiter && elem->min_wait_seq_no <= seq_no)
{
/*
Someone was waiting in MASTER_GTID_WAIT() for this GTID to appear.
Signal (and remove) them. The waiter will handle all the processing
of all pending MASTER_GTID_WAIT(), so we do not slow down the
replication SQL thread.
*/
mysql_mutex_assert_owner(&LOCK_slave_state);
elem->gtid_waiter= NULL;
mysql_cond_broadcast(&elem->COND_wait_gtid);
}
if (rgi)
{
if (rgi->gtid_ignore_duplicate_state==rpl_group_info::GTID_DUPLICATE_OWNER)
{
#ifdef DBUG_ASSERT_EXISTS
Relay_log_info *rli= rgi->rli;
#endif
uint32 count= elem->owner_count;
DBUG_ASSERT(count > 0);
DBUG_ASSERT(elem->owner_rli == rli);
--count;
elem->owner_count= count;
if (count == 0)
{
elem->owner_rli= NULL;
mysql_cond_broadcast(&elem->COND_gtid_ignore_duplicates);
}
}
rgi->gtid_ignore_duplicate_state= rpl_group_info::GTID_DUPLICATE_NULL;
}
if (!(list_elem= (list_element *)my_malloc(PSI_INSTRUMENT_ME,
sizeof(*list_elem), MYF(MY_WME))))
return 1;
list_elem->domain_id= domain_id;
list_elem->server_id= server_id;
list_elem->sub_id= sub_id;
list_elem->seq_no= seq_no;
list_elem->hton= hton;
elem->add(list_elem);
if (last_sub_id < sub_id)
last_sub_id= sub_id;
#ifdef HAVE_REPLICATION
++pending_gtid_count;
if (pending_gtid_count >= opt_gtid_cleanup_batch_size)
{
pending_gtid_count = 0;
slave_background_gtid_pending_delete_request();
}
#endif
return 0;
}
struct rpl_slave_state::element *
rpl_slave_state::get_element(uint32 domain_id)
{
struct element *elem;
elem= (element *)my_hash_search(&hash, (const uchar *)&domain_id, 0);
if (elem)
return elem;
if (!(elem= (element *)my_malloc(PSI_INSTRUMENT_ME, sizeof(*elem), MYF(MY_WME))))
return NULL;
elem->list= NULL;
elem->domain_id= domain_id;
elem->highest_seq_no= 0;
elem->gtid_waiter= NULL;
elem->owner_rli= NULL;
elem->owner_count= 0;
mysql_cond_init(key_COND_wait_gtid, &elem->COND_wait_gtid, 0);
mysql_cond_init(key_COND_gtid_ignore_duplicates,
&elem->COND_gtid_ignore_duplicates, 0);
if (my_hash_insert(&hash, (uchar *)elem))
{
my_free(elem);
return NULL;
}
return elem;
}
int
rpl_slave_state::put_back_list(list_element *list)
{
element *e= NULL;
int err= 0;
mysql_mutex_lock(&LOCK_slave_state);
while (list)
{
list_element *next= list->next;
if ((!e || e->domain_id != list->domain_id) &&
!(e= (element *)my_hash_search(&hash, (const uchar *)&list->domain_id, 0)))
{
err= 1;
goto end;
}
e->add(list);
list= next;
}
end:
mysql_mutex_unlock(&LOCK_slave_state);
return err;
}
int
rpl_slave_state::truncate_state_table(THD *thd)
{
TABLE_LIST tlist;
int err= 0;
tlist.init_one_table(&MYSQL_SCHEMA_NAME, &rpl_gtid_slave_state_table_name,
NULL, TL_WRITE);
tlist.mdl_request.set_type(MDL_EXCLUSIVE);
if (!(err= open_and_lock_tables(thd, &tlist, FALSE,
MYSQL_OPEN_IGNORE_LOGGING_FORMAT)))
{
DBUG_ASSERT(!tlist.table->file->row_logging);
tlist.table->s->tdc->flush(thd, true);
err= tlist.table->file->ha_truncate();
if (err)
{
ha_rollback_trans(thd, FALSE);
close_thread_tables(thd);
ha_rollback_trans(thd, TRUE);
}
else
{
ha_commit_trans(thd, FALSE);
close_thread_tables(thd);
ha_commit_trans(thd, TRUE);
}
thd->mdl_context.release_transactional_locks();
}
return err;
}
static const TABLE_FIELD_TYPE mysql_rpl_slave_state_coltypes[4]= {
{ { STRING_WITH_LEN("domain_id") },
{ STRING_WITH_LEN("int(10) unsigned") },
{NULL, 0} },
{ { STRING_WITH_LEN("sub_id") },
{ STRING_WITH_LEN("bigint(20) unsigned") },
{NULL, 0} },
{ { STRING_WITH_LEN("server_id") },
{ STRING_WITH_LEN("int(10) unsigned") },
{NULL, 0} },
{ { STRING_WITH_LEN("seq_no") },
{ STRING_WITH_LEN("bigint(20) unsigned") },
{NULL, 0} },
};
static const uint mysql_rpl_slave_state_pk_parts[]= {0, 1};
static const TABLE_FIELD_DEF mysql_gtid_slave_pos_tabledef= {
array_elements(mysql_rpl_slave_state_coltypes),
mysql_rpl_slave_state_coltypes,
array_elements(mysql_rpl_slave_state_pk_parts),
mysql_rpl_slave_state_pk_parts
};
static Table_check_intact_log_error gtid_table_intact;
/*
Check that the mysql.gtid_slave_pos table has the correct definition.
*/
int
gtid_check_rpl_slave_state_table(TABLE *table)
{
int err;
if ((err= gtid_table_intact.check(table, &mysql_gtid_slave_pos_tabledef)))
my_error(ER_GTID_OPEN_TABLE_FAILED, MYF(0), "mysql",
rpl_gtid_slave_state_table_name.str);
return err;
}
/*
Attempt to find a mysql.gtid_slave_posXXX table that has a storage engine
that is already in use by the current transaction, if any.
*/
void
rpl_slave_state::select_gtid_pos_table(THD *thd, LEX_CSTRING *out_tablename)
{
/*
See comments on rpl_slave_state::gtid_pos_tables for rules around proper
access to the list.
*/
auto list= gtid_pos_tables.load(std::memory_order_acquire);
Ha_trx_info *ha_info;
uint count = 0;
for (ha_info= thd->transaction->all.ha_list; ha_info; ha_info= ha_info->next())
{
void *trx_hton= ha_info->ht();
auto table_entry= list;
if (!ha_info->is_trx_read_write() || trx_hton == binlog_hton)
continue;
while (table_entry)
{
if (table_entry->table_hton == trx_hton)
{
if (likely(table_entry->state == GTID_POS_AVAILABLE))
{
*out_tablename= table_entry->table_name;
/*
Check if this is a cross-engine transaction, so we can correctly
maintain the rpl_transactions_multi_engine status variable.
*/
if (count >= 1)
statistic_increment(rpl_transactions_multi_engine, LOCK_status);
else
{
for (;;)
{
ha_info= ha_info->next();
if (!ha_info)
break;
if (ha_info->is_trx_read_write() && ha_info->ht() != binlog_hton)
{
statistic_increment(rpl_transactions_multi_engine, LOCK_status);
break;
}
}
}
return;
}
/*
This engine is marked to automatically create the table.
We cannot easily do this here (possibly in the middle of a
transaction). But we can request the slave background thread
to create it, and in a short while it should become available
for following transactions.
*/
#ifdef HAVE_REPLICATION
slave_background_gtid_pos_create_request(table_entry);
#endif
break;
}
table_entry= table_entry->next;
}
++count;
}
/*
If we cannot find any table whose engine matches an engine that is
already active in the transaction, or if there is no current transaction
engines available, we return the default gtid_slave_pos table.
*/
*out_tablename=
default_gtid_pos_table.load(std::memory_order_acquire)->table_name;
/* Record in status that we failed to find a suitable gtid_pos table. */
if (count > 0)
{
statistic_increment(transactions_gtid_foreign_engine, LOCK_status);
if (count > 1)
statistic_increment(rpl_transactions_multi_engine, LOCK_status);
}
}
/*
Write a gtid to the replication slave state table.
Do it as part of the transaction, to get slave crash safety, or as a separate
transaction if !in_transaction (eg. MyISAM or DDL).
gtid The global transaction id for this event group.
sub_id Value allocated within the sub_id when the event group was
read (sub_id must be consistent with commit order in master binlog).
Note that caller must later ensure that the new gtid and sub_id is inserted
into the appropriate HASH element with rpl_slave_state.add(), so that it can
be deleted later. But this must only be done after COMMIT if in transaction.
*/
int
rpl_slave_state::record_gtid(THD *thd, const rpl_gtid *gtid, uint64 sub_id,
bool in_transaction, bool in_statement,
void **out_hton)
{
TABLE_LIST tlist;
int err= 0, not_sql_thread;
bool table_opened= false;
TABLE *table;
ulonglong thd_saved_option= thd->variables.option_bits;
Query_tables_list lex_backup;
wait_for_commit* suspended_wfc;
void *hton= NULL;
LEX_CSTRING gtid_pos_table_name;
DBUG_ENTER("record_gtid");
*out_hton= NULL;
if (unlikely(!loaded))
{
/*
Probably the mysql.gtid_slave_pos table is missing (eg. upgrade) or
corrupt.
We already complained loudly about this, but we can try to continue
until the DBA fixes it.
*/
DBUG_RETURN(0);
}
if (!in_statement)
thd->reset_for_next_command();
/*
Only the SQL thread can call select_gtid_pos_table without a mutex
Other threads needs to use a mutex and take into account that the
result may change during execution, so we have to make a copy.
*/
if ((not_sql_thread= (thd->system_thread != SYSTEM_THREAD_SLAVE_SQL)))
mysql_mutex_lock(&LOCK_slave_state);
select_gtid_pos_table(thd, &gtid_pos_table_name);
if (not_sql_thread)
{
LEX_CSTRING *tmp= thd->make_clex_string(gtid_pos_table_name.str,
gtid_pos_table_name.length);
mysql_mutex_unlock(&LOCK_slave_state);
if (!tmp)
DBUG_RETURN(1);
gtid_pos_table_name= *tmp;
}
DBUG_EXECUTE_IF("gtid_inject_record_gtid",
{
my_error(ER_CANNOT_UPDATE_GTID_STATE, MYF(0));
DBUG_RETURN(1);
} );
/*
If we are applying a non-transactional event group, we will be committing
here a transaction, but that does not imply that the event group has
completed or has been binlogged. So we should not trigger
wakeup_subsequent_commits() here.
Note: An alternative here could be to put a call to mark_start_commit() in
stmt_done() before the call to record_and_update_gtid(). This would
prevent later calling mark_start_commit() after we have run
wakeup_subsequent_commits() from committing the GTID update transaction
(which must be avoided to avoid accessing freed group_commit_orderer
object). It would also allow following event groups to start slightly
earlier. And in the cases where record_gtid() is called without an active
transaction, the current statement should have been binlogged already, so
binlog order is preserved.
But this is rather subtle, and potentially fragile. And it does not really
seem worth it; non-transactional loads are unlikely to benefit much from
parallel replication in any case. So for now, we go with the simple
suspend/resume of wakeup_subsequent_commits() here in record_gtid().
*/
suspended_wfc= thd->suspend_subsequent_commits();
thd->lex->reset_n_backup_query_tables_list(&lex_backup);
tlist.init_one_table(&MYSQL_SCHEMA_NAME, &gtid_pos_table_name, NULL, TL_WRITE);
if ((err= open_and_lock_tables(thd, &tlist, FALSE, 0)))
goto end;
table_opened= true;
table= tlist.table;
hton= table->s->db_type();
table->file->row_logging= 0; // No binary logging
if ((err= gtid_check_rpl_slave_state_table(table)))
goto end;
#ifdef WITH_WSREP
/*
Updates in slave state table should not be appended to galera transaction
writeset.
*/
thd->wsrep_ignore_table= true;
#endif
if (!in_transaction)
{
DBUG_PRINT("info", ("resetting OPTION_BEGIN"));
thd->variables.option_bits&=
~(ulonglong)(OPTION_NOT_AUTOCOMMIT |OPTION_BEGIN |OPTION_BIN_LOG |
OPTION_GTID_BEGIN);
}
else
thd->variables.option_bits&= ~(ulonglong)OPTION_BIN_LOG;
bitmap_set_all(table->write_set);
table->rpl_write_set= table->write_set;
table->field[0]->store((ulonglong)gtid->domain_id, true);
table->field[1]->store(sub_id, true);
table->field[2]->store((ulonglong)gtid->server_id, true);
table->field[3]->store(gtid->seq_no, true);
DBUG_EXECUTE_IF("inject_crash_before_write_rpl_slave_state", DBUG_SUICIDE(););
if ((err= table->file->ha_write_row(table->record[0])))
{
table->file->print_error(err, MYF(0));
goto end;
}
*out_hton= hton;
if(opt_bin_log &&
(err= mysql_bin_log.bump_seq_no_counter_if_needed(gtid->domain_id,
gtid->seq_no)))
{
my_error(ER_OUT_OF_RESOURCES, MYF(0));
goto end;
}
end:
#ifdef WITH_WSREP
thd->wsrep_ignore_table= false;
#endif
if (table_opened)
{
if (err || (err= ha_commit_trans(thd, FALSE)))
ha_rollback_trans(thd, FALSE);
close_thread_tables(thd);
if (in_transaction)
thd->mdl_context.release_statement_locks();
else
thd->mdl_context.release_transactional_locks();
}
thd->lex->restore_backup_query_tables_list(&lex_backup);
thd->variables.option_bits= thd_saved_option;
thd->resume_subsequent_commits(suspended_wfc);
DBUG_EXECUTE_IF("inject_record_gtid_serverid_100_sleep",
{
if (gtid->server_id == 100)
my_sleep(500000);
});
DBUG_RETURN(err);
}
/*
Return a list of all old GTIDs in any mysql.gtid_slave_pos* table that are
no longer needed and can be deleted from the table.
Within each domain, we need to keep around the latest GTID (the one with the
highest sub_id), but any others in that domain can be deleted.
*/
rpl_slave_state::list_element *
rpl_slave_state::gtid_grab_pending_delete_list()
{
uint32 i;
list_element *full_list;
mysql_mutex_lock(&LOCK_slave_state);
full_list= NULL;
for (i= 0; i < hash.records; ++i)
{
element *elem= (element *)my_hash_element(&hash, i);
list_element *elist= elem->list;
list_element *last_elem, **best_ptr_ptr, *cur, *next;
uint64 best_sub_id;
if (!elist)
continue; /* Nothing here */
/* Delete any old stuff, but keep around the most recent one. */
cur= elist;
best_sub_id= cur->sub_id;
best_ptr_ptr= &elist;
last_elem= cur;
while ((next= cur->next)) {
last_elem= next;
if (next->sub_id > best_sub_id)
{
best_sub_id= next->sub_id;
best_ptr_ptr= &cur->next;
}
cur= next;
}
/*
Append the new elements to the full list. Note the order is important;
we do it here so that we do not break the list if best_sub_id is the
last of the new elements.
*/
last_elem->next= full_list;
/*
Delete the highest sub_id element from the old list, and put it back as
the single-element new list.
*/
cur= *best_ptr_ptr;
*best_ptr_ptr= cur->next;
cur->next= NULL;
elem->list= cur;
/*
Collect the full list so far here. Note that elist may have moved if we
deleted the first element, so order is again important.
*/
full_list= elist;
}
mysql_mutex_unlock(&LOCK_slave_state);
return full_list;
}
/* Find the mysql.gtid_slave_posXXX table associated with a given hton. */
LEX_CSTRING *
rpl_slave_state::select_gtid_pos_table(void *hton)
{
/*
See comments on rpl_slave_state::gtid_pos_tables for rules around proper
access to the list.
*/
auto table_entry= gtid_pos_tables.load(std::memory_order_acquire);
while (table_entry)
{
if (table_entry->table_hton == hton)
{
if (likely(table_entry->state == GTID_POS_AVAILABLE))
return &table_entry->table_name;
}
table_entry= table_entry->next;
}
return &default_gtid_pos_table.load(std::memory_order_acquire)->table_name;
}
void
rpl_slave_state::gtid_delete_pending(THD *thd,
rpl_slave_state::list_element **list_ptr)
{
int err= 0;
ulonglong thd_saved_option;
if (unlikely(!loaded))
return;
#ifdef WITH_WSREP
/*
Updates in slave state table should not be appended to galera transaction
writeset.
*/
thd->wsrep_ignore_table= true;
#endif
thd_saved_option= thd->variables.option_bits;
thd->variables.option_bits&=
~(ulonglong)(OPTION_NOT_AUTOCOMMIT |OPTION_BEGIN |OPTION_BIN_LOG |
OPTION_GTID_BEGIN);
while (*list_ptr)
{
LEX_CSTRING *gtid_pos_table_name, *tmp_table_name;
Query_tables_list lex_backup;
TABLE_LIST tlist;
TABLE *table;
handler::Table_flags direct_pos= 0;
list_element *cur, **cur_ptr_ptr;
bool table_opened= false;
bool index_inited= false;
void *hton= (*list_ptr)->hton;
thd->reset_for_next_command();
/*
Only the SQL thread can call select_gtid_pos_table without a mutex
Other threads needs to use a mutex and take into account that the
result may change during execution, so we have to make a copy.
*/
mysql_mutex_lock(&LOCK_slave_state);
tmp_table_name= select_gtid_pos_table(hton);
gtid_pos_table_name= thd->make_clex_string(tmp_table_name->str,
tmp_table_name->length);
mysql_mutex_unlock(&LOCK_slave_state);
if (!gtid_pos_table_name)
{
/* Out of memory - we can try again later. */
break;
}
thd->lex->reset_n_backup_query_tables_list(&lex_backup);
tlist.init_one_table(&MYSQL_SCHEMA_NAME, gtid_pos_table_name, NULL, TL_WRITE);
if ((err= open_and_lock_tables(thd, &tlist, FALSE, 0)))
goto end;
table_opened= true;
table= tlist.table;
if ((err= gtid_check_rpl_slave_state_table(table)))
goto end;
direct_pos= table->file->ha_table_flags() & HA_PRIMARY_KEY_REQUIRED_FOR_POSITION;
bitmap_set_all(table->write_set);
table->rpl_write_set= table->write_set;
/* Now delete any already committed GTIDs. */
bitmap_set_bit(table->read_set, table->field[0]->field_index);
bitmap_set_bit(table->read_set, table->field[1]->field_index);
if (!direct_pos)
{
if ((err= table->file->ha_index_init(0, 0)))
{
table->file->print_error(err, MYF(0));
goto end;
}
index_inited= true;
}
cur = *list_ptr;
cur_ptr_ptr = list_ptr;
do
{
uchar key_buffer[4+8];
list_element *next= cur->next;
if (cur->hton == hton)
{
int res;
table->field[0]->store((ulonglong)cur->domain_id, true);
table->field[1]->store(cur->sub_id, true);
if (direct_pos)
{
res= table->file->ha_rnd_pos_by_record(table->record[0]);
}
else
{
key_copy(key_buffer, table->record[0], &table->key_info[0], 0, false);
res= table->file->ha_index_read_map(table->record[0], key_buffer,
HA_WHOLE_KEY, HA_READ_KEY_EXACT);
}
DBUG_EXECUTE_IF("gtid_slave_pos_simulate_failed_delete",
{ res= 1;
err= ENOENT;
sql_print_error("<DEBUG> Error deleting old GTID row");
});
if (res)
/* We cannot find the row, assume it is already deleted. */
;
else if ((err= table->file->ha_delete_row(table->record[0])))
{
sql_print_error("Error deleting old GTID row: %s",
thd->get_stmt_da()->message());
/*
In case of error, we still discard the element from the list. We do
not want to endlessly error on the same element in case of table
corruption or such.
*/
}
*cur_ptr_ptr= next;
my_free(cur);
}
else
{
/* Leave this one in the list until we get to the table for its hton. */
cur_ptr_ptr= &cur->next;
}
cur= next;
if (err)
break;
} while (cur);
end:
if (table_opened)
{
DBUG_ASSERT(direct_pos || index_inited || err);
/*
Index may not be initialized if there was a failure during
'ha_index_init'. Hence check if index initialization is successful and
then invoke ha_index_end(). Ending an index which is not initialized
will lead to assert.
*/
if (index_inited)
table->file->ha_index_end();
if (err || (err= ha_commit_trans(thd, FALSE)))
ha_rollback_trans(thd, FALSE);
}
close_thread_tables(thd);
thd->mdl_context.release_transactional_locks();
thd->lex->restore_backup_query_tables_list(&lex_backup);
if (err)
break;
}
thd->variables.option_bits= thd_saved_option;
#ifdef WITH_WSREP
thd->wsrep_ignore_table= false;
#endif
}
uint64
rpl_slave_state::next_sub_id(uint32 domain_id)
{
uint64 sub_id= 0;
mysql_mutex_lock(&LOCK_slave_state);
sub_id= ++last_sub_id;
mysql_mutex_unlock(&LOCK_slave_state);
return sub_id;
}
/* A callback used in sorting of gtid list based on domain_id. */
static int rpl_gtid_cmp_cb(const void *id1, const void *id2)
{
uint32 d1= ((rpl_gtid *)id1)->domain_id;
uint32 d2= ((rpl_gtid *)id2)->domain_id;
if (d1 < d2)
return -1;
else if (d1 > d2)
return 1;
return 0;
}
/* Format the specified gtid and store it in the given string buffer. */
bool
rpl_slave_state_tostring_helper(String *dest, const rpl_gtid *gtid, bool *first)
{
if (*first)
*first= false;
else
if (dest->append(",",1))
return true;
return
dest->append_ulonglong(gtid->domain_id) ||
dest->append("-",1) ||
dest->append_ulonglong(gtid->server_id) ||
dest->append("-",1) ||
dest->append_ulonglong(gtid->seq_no);
}
/*
Sort the given gtid list based on domain_id and store them in the specified
string.
*/
static bool
rpl_slave_state_tostring_helper(DYNAMIC_ARRAY *gtid_dynarr, String *str)
{
bool first= true, res= true;
sort_dynamic(gtid_dynarr, rpl_gtid_cmp_cb);
for (uint i= 0; i < gtid_dynarr->elements; i ++)
{
rpl_gtid *gtid= dynamic_element(gtid_dynarr, i, rpl_gtid *);
if (rpl_slave_state_tostring_helper(str, gtid, &first))
goto err;
}
res= false;
err:
return res;
}
/* Sort the given gtid list based on domain_id and call cb for each gtid. */
static bool
rpl_slave_state_tostring_helper(DYNAMIC_ARRAY *gtid_dynarr,
int (*cb)(rpl_gtid *, void *),
void *data)
{
rpl_gtid *gtid;
bool res= true;
sort_dynamic(gtid_dynarr, rpl_gtid_cmp_cb);
for (uint i= 0; i < gtid_dynarr->elements; i ++)
{
gtid= dynamic_element(gtid_dynarr, i, rpl_gtid *);
if ((*cb)(gtid, data))
goto err;
}
res= false;
err:
return res;
}
int
rpl_slave_state::iterate(int (*cb)(rpl_gtid *, void *), void *data,
rpl_gtid *extra_gtids, uint32 num_extra,
bool sort)
{
uint32 i;
HASH gtid_hash;
uchar *rec;
rpl_gtid *gtid;
int res= 1;
bool locked= false;
my_hash_init(PSI_INSTRUMENT_ME, &gtid_hash, &my_charset_bin, 32,
offsetof(rpl_gtid, domain_id), sizeof(uint32), NULL, NULL,
HASH_UNIQUE);
for (i= 0; i < num_extra; ++i)
if (extra_gtids[i].server_id == global_system_variables.server_id &&
my_hash_insert(&gtid_hash, (uchar *)(&extra_gtids[i])))
goto err;
mysql_mutex_lock(&LOCK_slave_state);
locked= true;
reset_dynamic(&gtid_sort_array);
for (i= 0; i < hash.records; ++i)
{
uint64 best_sub_id;
rpl_gtid best_gtid;
element *e= (element *)my_hash_element(&hash, i);
list_element *l= e->list;
if (!l)
continue; /* Nothing here */
best_gtid.domain_id= e->domain_id;
best_gtid.server_id= l->server_id;
best_gtid.seq_no= l->seq_no;
best_sub_id= l->sub_id;
while ((l= l->next))
{
if (l->sub_id > best_sub_id)
{
best_sub_id= l->sub_id;
best_gtid.server_id= l->server_id;
best_gtid.seq_no= l->seq_no;
}
}
/* Check if we have something newer in the extra list. */
rec= my_hash_search(&gtid_hash, (const uchar *)&best_gtid.domain_id, 0);
if (rec)
{
gtid= (rpl_gtid *)rec;
if (gtid->seq_no > best_gtid.seq_no)
memcpy(&best_gtid, gtid, sizeof(best_gtid));
if (my_hash_delete(&gtid_hash, rec))
{
goto err;
}
}
if ((res= sort ? insert_dynamic(&gtid_sort_array,
(const void *) &best_gtid) :
(*cb)(&best_gtid, data)))
{
goto err;
}
}
/* Also add any remaining extra domain_ids. */
for (i= 0; i < gtid_hash.records; ++i)
{
gtid= (rpl_gtid *)my_hash_element(&gtid_hash, i);
if ((res= sort ? insert_dynamic(&gtid_sort_array, (const void *) gtid) :
(*cb)(gtid, data)))
{
goto err;
}
}
if (sort && rpl_slave_state_tostring_helper(&gtid_sort_array, cb, data))
{
goto err;
}
res= 0;
err:
if (locked) mysql_mutex_unlock(&LOCK_slave_state);
my_hash_free(&gtid_hash);
return res;
}
struct rpl_slave_state_tostring_data {
String *dest;
bool first;
};
static int
rpl_slave_state_tostring_cb(rpl_gtid *gtid, void *data)
{
rpl_slave_state_tostring_data *p= (rpl_slave_state_tostring_data *)data;
return rpl_slave_state_tostring_helper(p->dest, gtid, &p->first);
}
/*
Prepare the current slave state as a string, suitable for sending to the
master to request to receive binlog events starting from that GTID state.
The state consists of the most recently applied GTID for each domain_id,
ie. the one with the highest sub_id within each domain_id.
Optinally, extra_gtids is a list of GTIDs from the binlog. This is used when
a server was previously a master and now needs to connect to a new master as
a slave. For each domain_id, if the GTID in the binlog was logged with our
own server_id _and_ has a higher seq_no than what is in the slave state,
then this should be used as the position to start replicating at. This
allows to promote a slave as new master, and connect the old master as a
slave with MASTER_GTID_POS=AUTO.
*/
int
rpl_slave_state::tostring(String *dest, rpl_gtid *extra_gtids, uint32 num_extra)
{
struct rpl_slave_state_tostring_data data;
data.first= true;
data.dest= dest;
return iterate(rpl_slave_state_tostring_cb, &data, extra_gtids,
num_extra, true);
}
/*
Lookup a domain_id in the current replication slave state.
Returns false if the domain_id has no entries in the slave state.
Otherwise returns true, and fills in out_gtid with the corresponding
GTID.
*/
bool
rpl_slave_state::domain_to_gtid(uint32 domain_id, rpl_gtid *out_gtid)
{
element *elem;
list_element *list;
uint64 best_sub_id;
mysql_mutex_lock(&LOCK_slave_state);
elem= (element *)my_hash_search(&hash, (const uchar *)&domain_id, 0);
if (!elem || !(list= elem->list))
{
mysql_mutex_unlock(&LOCK_slave_state);
return false;
}
out_gtid->domain_id= domain_id;
out_gtid->server_id= list->server_id;
out_gtid->seq_no= list->seq_no;
best_sub_id= list->sub_id;
while ((list= list->next))
{
if (best_sub_id > list->sub_id)
continue;
best_sub_id= list->sub_id;
out_gtid->server_id= list->server_id;
out_gtid->seq_no= list->seq_no;
}
mysql_mutex_unlock(&LOCK_slave_state);
return true;
}
/*
Parse a GTID at the start of a string, and update the pointer to point
at the first character after the parsed GTID.
Returns 0 on ok, non-zero on parse error.
*/
static int
gtid_parser_helper(const char **ptr, const char *end, rpl_gtid *out_gtid)
{
char *q;
const char *p= *ptr;
uint64 v1, v2, v3;
int err= 0;
q= (char*) end;
v1= (uint64)my_strtoll10(p, &q, &err);
if (err != 0 || v1 > (uint32)0xffffffff || q == end || *q != '-')
return 1;
p= q+1;
q= (char*) end;
v2= (uint64)my_strtoll10(p, &q, &err);
if (err != 0 || v2 > (uint32)0xffffffff || q == end || *q != '-')
return 1;
p= q+1;
q= (char*) end;
v3= (uint64)my_strtoll10(p, &q, &err);
if (err != 0)
return 1;
out_gtid->domain_id= (uint32) v1;
out_gtid->server_id= (uint32) v2;
out_gtid->seq_no= v3;
*ptr= q;
return 0;
}
rpl_gtid *
gtid_parse_string_to_list(const char *str, size_t str_len, uint32 *out_len)
{
const char *p= const_cast<char *>(str);
const char *end= p + str_len;
uint32 len= 0, alloc_len= 5;
rpl_gtid *list= NULL;
for (;;)
{
rpl_gtid gtid;
if (len >= (((uint32)1 << 28)-1) || gtid_parser_helper(&p, end, &gtid))
{
my_free(list);
return NULL;
}
if ((!list || len >= alloc_len) &&
!(list=
(rpl_gtid *)my_realloc(PSI_INSTRUMENT_ME, list,
(alloc_len= alloc_len*2) * sizeof(rpl_gtid),
MYF(MY_FREE_ON_ERROR|MY_ALLOW_ZERO_PTR))))
return NULL;
list[len++]= gtid;
if (p == end)
break;
if (*p != ',')
{
my_free(list);
return NULL;
}
++p;
}
*out_len= len;
return list;
}
/*
Update the slave replication state with the GTID position obtained from
master when connecting with old-style (filename,offset) position.
If RESET is true then all existing entries are removed. Otherwise only
domain_ids mentioned in the STATE_FROM_MASTER are changed.
Returns 0 if ok, non-zero if error.
*/
int
rpl_slave_state::load(THD *thd, const char *state_from_master, size_t len,
bool reset, bool in_statement)
{
const char *end= state_from_master + len;
if (reset)
{
if (truncate_state_table(thd))
return 1;
truncate_hash();
}
if (state_from_master == end)
return 0;
for (;;)
{
rpl_gtid gtid;
uint64 sub_id;
void *hton= NULL;
if (gtid_parser_helper(&state_from_master, end, &gtid) ||
!(sub_id= next_sub_id(gtid.domain_id)) ||
record_gtid(thd, &gtid, sub_id, false, in_statement, &hton) ||
update(gtid.domain_id, gtid.server_id, sub_id, gtid.seq_no, hton, NULL))
return 1;
if (state_from_master == end)
break;
if (*state_from_master != ',')
return 1;
++state_from_master;
}
return 0;
}
bool
rpl_slave_state::is_empty()
{
uint32 i;
bool result= true;
mysql_mutex_lock(&LOCK_slave_state);
for (i= 0; i < hash.records; ++i)
{
element *e= (element *)my_hash_element(&hash, i);
if (e->list)
{
result= false;
break;
}
}
mysql_mutex_unlock(&LOCK_slave_state);
return result;
}
void
rpl_slave_state::free_gtid_pos_tables(struct rpl_slave_state::gtid_pos_table *list)
{
struct gtid_pos_table *cur, *next;
cur= list;
while (cur)
{
next= cur->next;
my_free(cur);
cur= next;
}
}
/*
Replace the list of available mysql.gtid_slave_posXXX tables with a new list.
The caller must be holding LOCK_slave_state. Additionally, this function
must only be called while all SQL threads are stopped.
*/
void
rpl_slave_state::set_gtid_pos_tables_list(rpl_slave_state::gtid_pos_table *new_list,
rpl_slave_state::gtid_pos_table *default_entry)
{
mysql_mutex_assert_owner(&LOCK_slave_state);
auto old_list= gtid_pos_tables.load(std::memory_order_relaxed);
gtid_pos_tables.store(new_list, std::memory_order_release);
default_gtid_pos_table.store(default_entry, std::memory_order_release);
free_gtid_pos_tables(old_list);
}
void
rpl_slave_state::add_gtid_pos_table(rpl_slave_state::gtid_pos_table *entry)
{
mysql_mutex_assert_owner(&LOCK_slave_state);
entry->next= gtid_pos_tables.load(std::memory_order_relaxed);
gtid_pos_tables.store(entry, std::memory_order_release);
}
struct rpl_slave_state::gtid_pos_table *
rpl_slave_state::alloc_gtid_pos_table(LEX_CSTRING *table_name, void *hton,
rpl_slave_state::gtid_pos_table_state state)
{
struct gtid_pos_table *p;
char *allocated_str;
if (!my_multi_malloc(PSI_INSTRUMENT_ME, MYF(MY_WME), &p, sizeof(*p),
&allocated_str, table_name->length+1, NULL))
{
my_error(ER_OUTOFMEMORY, MYF(0), (int)(sizeof(*p) + table_name->length+1));
return NULL;
}
memcpy(allocated_str, table_name->str, table_name->length+1); // Also copy '\0'
p->next = NULL;
p->table_hton= hton;
p->table_name.str= allocated_str;
p->table_name.length= table_name->length;
p->state= state;
return p;
}
void rpl_binlog_state::init()
{
my_hash_init(PSI_INSTRUMENT_ME, &hash, &my_charset_bin, 32, offsetof(element, domain_id),
sizeof(uint32), NULL, my_free, HASH_UNIQUE);
my_init_dynamic_array(PSI_INSTRUMENT_ME, &gtid_sort_array, sizeof(rpl_gtid), 8, 8, MYF(0));
mysql_mutex_init(key_LOCK_binlog_state, &LOCK_binlog_state,
MY_MUTEX_INIT_SLOW);
initialized= 1;
}
void
rpl_binlog_state::reset_nolock()
{
uint32 i;
for (i= 0; i < hash.records; ++i)
my_hash_free(&((element *)my_hash_element(&hash, i))->hash);
my_hash_reset(&hash);
}
void
rpl_binlog_state::reset()
{
mysql_mutex_lock(&LOCK_binlog_state);
reset_nolock();
mysql_mutex_unlock(&LOCK_binlog_state);
}
void rpl_binlog_state::free()
{
if (initialized)
{
initialized= 0;
reset_nolock();
my_hash_free(&hash);
delete_dynamic(&gtid_sort_array);
mysql_mutex_destroy(&LOCK_binlog_state);
}
}
bool
rpl_binlog_state::load(struct rpl_gtid *list, uint32 count)
{
uint32 i;
bool res= false;
mysql_mutex_lock(&LOCK_binlog_state);
reset_nolock();
for (i= 0; i < count; ++i)
{
if (update_nolock(&(list[i]), false))
{
res= true;
break;
}
}
mysql_mutex_unlock(&LOCK_binlog_state);
return res;
}
static int rpl_binlog_state_load_cb(rpl_gtid *gtid, void *data)
{
rpl_binlog_state *self= (rpl_binlog_state *)data;
return self->update_nolock(gtid, false);
}
bool
rpl_binlog_state::load(rpl_slave_state *slave_pos)
{
bool res= false;
mysql_mutex_lock(&LOCK_binlog_state);
reset_nolock();
if (slave_pos->iterate(rpl_binlog_state_load_cb, this, NULL, 0, false))
res= true;
mysql_mutex_unlock(&LOCK_binlog_state);
return res;
}
rpl_binlog_state::~rpl_binlog_state()
{
free();
}
/*
Update replication state with a new GTID.
If the (domain_id, server_id) pair already exists, then the new GTID replaces
the old one for that domain id. Else a new entry is inserted.
Returns 0 for ok, 1 for error.
*/
int
rpl_binlog_state::update_nolock(const struct rpl_gtid *gtid, bool strict)
{
element *elem;
if ((elem= (element *)my_hash_search(&hash,
(const uchar *)(&gtid->domain_id), 0)))
{
if (strict && elem->last_gtid && elem->last_gtid->seq_no >= gtid->seq_no)
{
my_error(ER_GTID_STRICT_OUT_OF_ORDER, MYF(0), gtid->domain_id,
gtid->server_id, gtid->seq_no, elem->last_gtid->domain_id,
elem->last_gtid->server_id, elem->last_gtid->seq_no);
return 1;
}
if (elem->seq_no_counter < gtid->seq_no)
elem->seq_no_counter= gtid->seq_no;
if (!elem->update_element(gtid))
return 0;
}
else if (!alloc_element_nolock(gtid))
return 0;
my_error(ER_OUT_OF_RESOURCES, MYF(0));
return 1;
}
int
rpl_binlog_state::update(const struct rpl_gtid *gtid, bool strict)
{
int res;
mysql_mutex_lock(&LOCK_binlog_state);
res= update_nolock(gtid, strict);
mysql_mutex_unlock(&LOCK_binlog_state);
return res;
}
/*
Fill in a new GTID, allocating next sequence number, and update state
accordingly.
*/
int
rpl_binlog_state::update_with_next_gtid(uint32 domain_id, uint32 server_id,
rpl_gtid *gtid)
{
element *elem;
int res= 0;
gtid->domain_id= domain_id;
gtid->server_id= server_id;
mysql_mutex_lock(&LOCK_binlog_state);
if ((elem= (element *)my_hash_search(&hash, (const uchar *)(&domain_id), 0)))
{
gtid->seq_no= ++elem->seq_no_counter;
if (!elem->update_element(gtid))
goto end;
}
else
{
gtid->seq_no= 1;
if (!alloc_element_nolock(gtid))
goto end;
}
my_error(ER_OUT_OF_RESOURCES, MYF(0));
res= 1;
end:
mysql_mutex_unlock(&LOCK_binlog_state);
return res;
}
/* Helper functions for update. */
int
rpl_binlog_state::element::update_element(const rpl_gtid *gtid)
{
rpl_gtid *lookup_gtid;
/*
By far the most common case is that successive events within same
replication domain have the same server id (it changes only when
switching to a new master). So save a hash lookup in this case.
*/
if (likely(last_gtid && last_gtid->server_id == gtid->server_id))
{
last_gtid->seq_no= gtid->seq_no;
return 0;
}
lookup_gtid= (rpl_gtid *)
my_hash_search(&hash, (const uchar *)&gtid->server_id, 0);
if (lookup_gtid)
{
lookup_gtid->seq_no= gtid->seq_no;
last_gtid= lookup_gtid;
return 0;
}
/* Allocate a new GTID and insert it. */
lookup_gtid= (rpl_gtid *)my_malloc(PSI_INSTRUMENT_ME, sizeof(*lookup_gtid),
MYF(MY_WME));
if (!lookup_gtid)
return 1;
memcpy(lookup_gtid, gtid, sizeof(*lookup_gtid));
if (my_hash_insert(&hash, (const uchar *)lookup_gtid))
{
my_free(lookup_gtid);
return 1;
}
last_gtid= lookup_gtid;
return 0;
}
int
rpl_binlog_state::alloc_element_nolock(const rpl_gtid *gtid)
{
element *elem;
rpl_gtid *lookup_gtid;
/* First time we see this domain_id; allocate a new element. */
elem= (element *)my_malloc(PSI_INSTRUMENT_ME, sizeof(*elem), MYF(MY_WME));
lookup_gtid= (rpl_gtid *)my_malloc(PSI_INSTRUMENT_ME, sizeof(*lookup_gtid),
MYF(MY_WME));
if (elem && lookup_gtid)
{
elem->domain_id= gtid->domain_id;
my_hash_init(PSI_INSTRUMENT_ME, &elem->hash, &my_charset_bin, 32,
offsetof(rpl_gtid, server_id), sizeof(uint32), NULL, my_free,
HASH_UNIQUE);
elem->last_gtid= lookup_gtid;
elem->seq_no_counter= gtid->seq_no;
memcpy(lookup_gtid, gtid, sizeof(*lookup_gtid));
if (0 == my_hash_insert(&elem->hash, (const uchar *)lookup_gtid))
{
lookup_gtid= NULL; /* Do not free. */
if (0 == my_hash_insert(&hash, (const uchar *)elem))
return 0;
}
my_hash_free(&elem->hash);
}
/* An error. */
if (elem)
my_free(elem);
if (lookup_gtid)
my_free(lookup_gtid);
return 1;
}
/*
Check that a new GTID can be logged without creating an out-of-order
sequence number with existing GTIDs.
*/
bool
rpl_binlog_state::check_strict_sequence(uint32 domain_id, uint32 server_id,
uint64 seq_no)
{
element *elem;
bool res= 0;
mysql_mutex_lock(&LOCK_binlog_state);
if ((elem= (element *)my_hash_search(&hash,
(const uchar *)(&domain_id), 0)) &&
elem->last_gtid && elem->last_gtid->seq_no >= seq_no)
{
my_error(ER_GTID_STRICT_OUT_OF_ORDER, MYF(0), domain_id, server_id, seq_no,
elem->last_gtid->domain_id, elem->last_gtid->server_id,
elem->last_gtid->seq_no);
res= 1;
}
mysql_mutex_unlock(&LOCK_binlog_state);
return res;
}
/*
When we see a new GTID that will not be binlogged (eg. slave thread
with --log-slave-updates=0), then we need to remember to allocate any
GTID seq_no of our own within that domain starting from there.
Returns 0 if ok, non-zero if out-of-memory.
*/
int
rpl_binlog_state::bump_seq_no_if_needed(uint32 domain_id, uint64 seq_no)
{
element *elem;
int res;
mysql_mutex_lock(&LOCK_binlog_state);
if ((elem= (element *)my_hash_search(&hash, (const uchar *)(&domain_id), 0)))
{
if (elem->seq_no_counter < seq_no)
elem->seq_no_counter= seq_no;
res= 0;
goto end;
}
/* We need to allocate a new, empty element to remember the next seq_no. */
if (!(elem= (element *)my_malloc(PSI_INSTRUMENT_ME, sizeof(*elem),
MYF(MY_WME))))
{
res= 1;
goto end;
}
elem->domain_id= domain_id;
my_hash_init(PSI_INSTRUMENT_ME, &elem->hash, &my_charset_bin, 32,
offsetof(rpl_gtid, server_id), sizeof(uint32), NULL, my_free,
HASH_UNIQUE);
elem->last_gtid= NULL;
elem->seq_no_counter= seq_no;
if (0 == my_hash_insert(&hash, (const uchar *)elem))
{
res= 0;
goto end;
}
my_hash_free(&elem->hash);
my_free(elem);
res= 1;
end:
mysql_mutex_unlock(&LOCK_binlog_state);
return res;
}
/*
Write binlog state to text file, so we can read it in again without having
to scan last binlog file (normal shutdown/startup, not crash recovery).
The most recent GTID within each domain_id is written after any other GTID
within this domain.
*/
int
rpl_binlog_state::write_to_iocache(IO_CACHE *dest)
{
ulong i, j;
char buf[21];
int res= 0;
mysql_mutex_lock(&LOCK_binlog_state);
for (i= 0; i < hash.records; ++i)
{
element *e= (element *)my_hash_element(&hash, i);
if (!e->last_gtid)
{
DBUG_ASSERT(e->hash.records == 0);
continue;
}
for (j= 0; j <= e->hash.records; ++j)
{
const rpl_gtid *gtid;
if (j < e->hash.records)
{
gtid= (const rpl_gtid *)my_hash_element(&e->hash, j);
if (gtid == e->last_gtid)
continue;
}
else
gtid= e->last_gtid;
longlong10_to_str(gtid->seq_no, buf, 10);
if (my_b_printf(dest, "%u-%u-%s\n", gtid->domain_id, gtid->server_id,
buf))
{
res= 1;
goto end;
}
}
}
end:
mysql_mutex_unlock(&LOCK_binlog_state);
return res;
}
int
rpl_binlog_state::read_from_iocache(IO_CACHE *src)
{
/* 10-digit - 10-digit - 20-digit \n \0 */
char buf[10+1+10+1+20+1+1];
const char *p, *end;
rpl_gtid gtid;
int res= 0;
mysql_mutex_lock(&LOCK_binlog_state);
reset_nolock();
for (;;)
{
size_t len= my_b_gets(src, buf, sizeof(buf));
if (!len)
break;
p= buf;
end= buf + len;
if (gtid_parser_helper(&p, end, &gtid) ||
update_nolock(&gtid, false))
{
res= 1;
break;
}
}
mysql_mutex_unlock(&LOCK_binlog_state);
return res;
}
rpl_gtid *
rpl_binlog_state::find_nolock(uint32 domain_id, uint32 server_id)
{
element *elem;
if (!(elem= (element *)my_hash_search(&hash, (const uchar *)&domain_id, 0)))
return NULL;
return (rpl_gtid *)my_hash_search(&elem->hash, (const uchar *)&server_id, 0);
}
rpl_gtid *
rpl_binlog_state::find(uint32 domain_id, uint32 server_id)
{
rpl_gtid *p;
mysql_mutex_lock(&LOCK_binlog_state);
p= find_nolock(domain_id, server_id);
mysql_mutex_unlock(&LOCK_binlog_state);
return p;
}
rpl_gtid *
rpl_binlog_state::find_most_recent(uint32 domain_id)
{
element *elem;
rpl_gtid *gtid= NULL;
mysql_mutex_lock(&LOCK_binlog_state);
elem= (element *)my_hash_search(&hash, (const uchar *)&domain_id, 0);
if (elem && elem->last_gtid)
gtid= elem->last_gtid;
mysql_mutex_unlock(&LOCK_binlog_state);
return gtid;
}
uint32
rpl_binlog_state::count()
{
uint32 c= 0;
uint32 i;
mysql_mutex_lock(&LOCK_binlog_state);
for (i= 0; i < hash.records; ++i)
c+= ((element *)my_hash_element(&hash, i))->hash.records;
mysql_mutex_unlock(&LOCK_binlog_state);
return c;
}
int
rpl_binlog_state::get_gtid_list(rpl_gtid *gtid_list, uint32 list_size)
{
uint32 i, j, pos;
int res= 0;
mysql_mutex_lock(&LOCK_binlog_state);
pos= 0;
for (i= 0; i < hash.records; ++i)
{
element *e= (element *)my_hash_element(&hash, i);
if (!e->last_gtid)
{
DBUG_ASSERT(e->hash.records==0);
continue;
}
for (j= 0; j <= e->hash.records; ++j)
{
const rpl_gtid *gtid;
if (j < e->hash.records)
{
gtid= (rpl_gtid *)my_hash_element(&e->hash, j);
if (gtid == e->last_gtid)
continue;
}
else
gtid= e->last_gtid;
if (pos >= list_size)
{
res= 1;
goto end;
}
memcpy(&gtid_list[pos++], gtid, sizeof(*gtid));
}
}
end:
mysql_mutex_unlock(&LOCK_binlog_state);
return res;
}
/*
Get a list of the most recently binlogged GTID, for each domain_id.
This can be used when switching from being a master to being a slave,
to know where to start replicating from the new master.
The returned list must be de-allocated with my_free().
Returns 0 for ok, non-zero for out-of-memory.
*/
int
rpl_binlog_state::get_most_recent_gtid_list(rpl_gtid **list, uint32 *size)
{
uint32 i;
uint32 alloc_size, out_size;
int res= 0;
out_size= 0;
mysql_mutex_lock(&LOCK_binlog_state);
alloc_size= hash.records;
if (!(*list= (rpl_gtid *)my_malloc(PSI_INSTRUMENT_ME,
alloc_size * sizeof(rpl_gtid), MYF(MY_WME))))
{
res= 1;
goto end;
}
for (i= 0; i < alloc_size; ++i)
{
element *e= (element *)my_hash_element(&hash, i);
if (!e->last_gtid)
continue;
memcpy(&((*list)[out_size++]), e->last_gtid, sizeof(rpl_gtid));
}
end:
mysql_mutex_unlock(&LOCK_binlog_state);
*size= out_size;
return res;
}
bool
rpl_binlog_state::append_pos(String *str)
{
uint32 i;
mysql_mutex_lock(&LOCK_binlog_state);
reset_dynamic(&gtid_sort_array);
for (i= 0; i < hash.records; ++i)
{
element *e= (element *)my_hash_element(&hash, i);
if (e->last_gtid &&
insert_dynamic(&gtid_sort_array, (const void *) e->last_gtid))
{
mysql_mutex_unlock(&LOCK_binlog_state);
return true;
}
}
rpl_slave_state_tostring_helper(&gtid_sort_array, str);
mysql_mutex_unlock(&LOCK_binlog_state);
return false;
}
bool
rpl_binlog_state::append_state(String *str)
{
uint32 i, j;
bool res= false;
mysql_mutex_lock(&LOCK_binlog_state);
reset_dynamic(&gtid_sort_array);
for (i= 0; i < hash.records; ++i)
{
element *e= (element *)my_hash_element(&hash, i);
if (!e->last_gtid)
{
DBUG_ASSERT(e->hash.records==0);
continue;
}
for (j= 0; j <= e->hash.records; ++j)
{
const rpl_gtid *gtid;
if (j < e->hash.records)
{
gtid= (rpl_gtid *)my_hash_element(&e->hash, j);
if (gtid == e->last_gtid)
continue;
}
else
gtid= e->last_gtid;
if (insert_dynamic(&gtid_sort_array, (const void *) gtid))
{
res= true;
goto end;
}
}
}
rpl_slave_state_tostring_helper(&gtid_sort_array, str);
end:
mysql_mutex_unlock(&LOCK_binlog_state);
return res;
}
/**
Remove domains supplied by the first argument from binlog state.
Removal is done for any domain whose last gtids (from all its servers) match
ones in Gtid list event of the 2nd argument.
@param ids gtid domain id sequence, may contain dups
@param glev pointer to Gtid list event describing
the match condition
@param errbuf [out] pointer to possible error message array
@retval NULL as success when at least one domain is removed
@retval "" empty string to indicate ineffective call
when no domains removed
@retval NOT EMPTY string otherwise an error message
*/
const char*
rpl_binlog_state::drop_domain(DYNAMIC_ARRAY *ids,
Gtid_list_log_event *glev,
char* errbuf)
{
DYNAMIC_ARRAY domain_unique; // sequece (unsorted) of unique element*:s
rpl_binlog_state::element* domain_unique_buffer[16];
ulong k, l;
const char* errmsg= NULL;
DBUG_ENTER("rpl_binlog_state::drop_domain");
my_init_dynamic_array2(PSI_INSTRUMENT_ME, &domain_unique,
sizeof(element*), domain_unique_buffer,
sizeof(domain_unique_buffer) / sizeof(element*), 4, 0);
mysql_mutex_lock(&LOCK_binlog_state);
/*
Gtid list is supposed to come from a binlog's Gtid_list event and
therefore should be a subset of the current binlog state. That is
for every domain in the list the binlog state contains a gtid with
sequence number not less than that of the list.
Exceptions of this inclusion rule are:
A. the list may still refer to gtids from already deleted domains.
Files containing them must have been purged whereas the file
with the list is not yet.
B. out of order groups were injected
C. manually build list of binlog files violating the inclusion
constraint.
While A is a normal case (not necessarily distinguishable from C though),
B and C may require the user's attention so any (incl the A's suspected)
inconsistency is diagnosed and *warned*.
*/
for (l= 0, errbuf[0]= 0; l < glev->count; l++, errbuf[0]= 0)
{
rpl_gtid* rb_state_gtid= find_nolock(glev->list[l].domain_id,
glev->list[l].server_id);
if (!rb_state_gtid)
sprintf(errbuf,
"missing gtids from the '%u-%u' domain-server pair which is "
"referred to in the gtid list describing an earlier state. Ignore "
"if the domain ('%u') was already explicitly deleted",
glev->list[l].domain_id, glev->list[l].server_id,
glev->list[l].domain_id);
else if (rb_state_gtid->seq_no < glev->list[l].seq_no)
sprintf(errbuf,
"having a gtid '%u-%u-%llu' which is less than "
"the '%u-%u-%llu' of the gtid list describing an earlier state. "
"The state may have been affected by manually injecting "
"a lower sequence number gtid or via replication",
rb_state_gtid->domain_id, rb_state_gtid->server_id,
rb_state_gtid->seq_no, glev->list[l].domain_id,
glev->list[l].server_id, glev->list[l].seq_no);
if (strlen(errbuf)) // use strlen() as cheap flag
push_warning_printf(current_thd, Sql_condition::WARN_LEVEL_WARN,
ER_BINLOG_CANT_DELETE_GTID_DOMAIN,
"The current gtid binlog state is incompatible with "
"a former one %s.", errbuf);
}
/*
For each domain_id from ids
when no such domain in binlog state
warn && continue
For each domain.server's last gtid
when not locate the last gtid in glev.list
error out binlog state can't change
otherwise continue
*/
for (ulong i= 0; i < ids->elements; i++)
{
rpl_binlog_state::element *elem= NULL;
uint32 *ptr_domain_id;
bool not_match;
ptr_domain_id= (uint32*) dynamic_array_ptr(ids, i);
elem= (rpl_binlog_state::element *)
my_hash_search(&hash, (const uchar *) ptr_domain_id, 0);
if (!elem)
{
push_warning_printf(current_thd, Sql_condition::WARN_LEVEL_WARN,
ER_BINLOG_CANT_DELETE_GTID_DOMAIN,
"The gtid domain being deleted ('%lu') is not in "
"the current binlog state", *ptr_domain_id);
continue;
}
for (not_match= true, k= 0; k < elem->hash.records; k++)
{
rpl_gtid *d_gtid= (rpl_gtid *)my_hash_element(&elem->hash, k);
for (ulong l= 0; l < glev->count && not_match; l++)
not_match= !(*d_gtid == glev->list[l]);
}
if (not_match)
{
sprintf(errbuf, "binlog files may contain gtids from the domain ('%u') "
"being deleted. Make sure to first purge those files",
*ptr_domain_id);
errmsg= errbuf;
goto end;
}
// compose a sequence of unique pointers to domain object
for (k= 0; k < domain_unique.elements; k++)
{
if ((rpl_binlog_state::element*) dynamic_array_ptr(&domain_unique, k)
== elem)
break; // domain_id's elem has been already in
}
if (k == domain_unique.elements) // proven not to have duplicates
insert_dynamic(&domain_unique, (uchar*) &elem);
}
// Domain removal from binlog state
for (k= 0; k < domain_unique.elements; k++)
{
rpl_binlog_state::element *elem= *(rpl_binlog_state::element**)
dynamic_array_ptr(&domain_unique, k);
my_hash_free(&elem->hash);
my_hash_delete(&hash, (uchar*) elem);
}
DBUG_ASSERT(strlen(errbuf) == 0);
if (domain_unique.elements == 0)
errmsg= "";
end:
mysql_mutex_unlock(&LOCK_binlog_state);
delete_dynamic(&domain_unique);
DBUG_RETURN(errmsg);
}
slave_connection_state::slave_connection_state()
{
my_hash_init(PSI_INSTRUMENT_ME, &hash, &my_charset_bin, 32,
offsetof(entry, gtid) + offsetof(rpl_gtid, domain_id),
sizeof(uint32), NULL, my_free, HASH_UNIQUE);
my_init_dynamic_array(PSI_INSTRUMENT_ME, &gtid_sort_array, sizeof(rpl_gtid), 8, 8, MYF(0));
}
slave_connection_state::~slave_connection_state()
{
my_hash_free(&hash);
delete_dynamic(&gtid_sort_array);
}
/*
Create a hash from the slave GTID state that is sent to master when slave
connects to start replication.
The state is sent as <GTID>,<GTID>,...,<GTID>, for example:
0-2-112,1-4-1022
The state gives for each domain_id the GTID to start replication from for
the corresponding replication stream. So domain_id must be unique.
Returns 0 if ok, non-zero if error due to malformed input.
Note that input string is built by slave server, so it will not be incorrect
unless bug/corruption/malicious server. So we just need basic sanity check,
not fancy user-friendly error message.
*/
int
slave_connection_state::load(const char *slave_request, size_t len)
{
const char *p, *end;
uchar *rec;
rpl_gtid *gtid;
const entry *e;
reset();
p= slave_request;
end= slave_request + len;
if (p == end)
return 0;
for (;;)
{
if (!(rec= (uchar *)my_malloc(PSI_INSTRUMENT_ME, sizeof(entry), MYF(MY_WME))))
return 1;
gtid= &((entry *)rec)->gtid;
if (gtid_parser_helper(&p, end, gtid))
{
my_free(rec);
my_error(ER_INCORRECT_GTID_STATE, MYF(0));
return 1;
}
if ((e= (const entry *)
my_hash_search(&hash, (const uchar *)(&gtid->domain_id), 0)))
{
my_error(ER_DUPLICATE_GTID_DOMAIN, MYF(0), gtid->domain_id,
gtid->server_id, (ulonglong)gtid->seq_no, e->gtid.domain_id,
e->gtid.server_id, (ulonglong)e->gtid.seq_no, gtid->domain_id);
my_free(rec);
return 1;
}
((entry *)rec)->flags= 0;
if (my_hash_insert(&hash, rec))
{
my_free(rec);
my_error(ER_OUT_OF_RESOURCES, MYF(0));
return 1;
}
if (p == end)
break; /* Finished. */
if (*p != ',')
{
my_error(ER_INCORRECT_GTID_STATE, MYF(0));
return 1;
}
++p;
}
return 0;
}
int
slave_connection_state::load(const rpl_gtid *gtid_list, uint32 count)
{
uint32 i;
reset();
for (i= 0; i < count; ++i)
if (update(&gtid_list[i]))
return 1;
return 0;
}
static int
slave_connection_state_load_cb(rpl_gtid *gtid, void *data)
{
slave_connection_state *state= (slave_connection_state *)data;
return state->update(gtid);
}
/*
Same as rpl_slave_state::tostring(), but populates a slave_connection_state
instead.
*/
int
slave_connection_state::load(rpl_slave_state *state,
rpl_gtid *extra_gtids, uint32 num_extra)
{
reset();
return state->iterate(slave_connection_state_load_cb, this,
extra_gtids, num_extra, false);
}
slave_connection_state::entry *
slave_connection_state::find_entry(uint32 domain_id)
{
return (entry *) my_hash_search(&hash, (const uchar *)(&domain_id), 0);
}
rpl_gtid *
slave_connection_state::find(uint32 domain_id)
{
entry *e= find_entry(domain_id);
if (!e)
return NULL;
return &e->gtid;
}
int
slave_connection_state::update(const rpl_gtid *in_gtid)
{
entry *e;
uchar *rec= my_hash_search(&hash, (const uchar *)(&in_gtid->domain_id), 0);
if (rec)
{
e= (entry *)rec;
e->gtid= *in_gtid;
return 0;
}
if (!(e= (entry *)my_malloc(PSI_INSTRUMENT_ME, sizeof(*e), MYF(MY_WME))))
return 1;
e->gtid= *in_gtid;
e->flags= 0;
if (my_hash_insert(&hash, (uchar *)e))
{
my_free(e);
return 1;
}
return 0;
}
void
slave_connection_state::remove(const rpl_gtid *in_gtid)
{
uchar *rec= my_hash_search(&hash, (const uchar *)(&in_gtid->domain_id), 0);
#ifdef DBUG_ASSERT_EXISTS
bool err;
rpl_gtid *slave_gtid= &((entry *)rec)->gtid;
DBUG_ASSERT(rec /* We should never try to remove not present domain_id. */);
DBUG_ASSERT(slave_gtid->server_id == in_gtid->server_id);
DBUG_ASSERT(slave_gtid->seq_no == in_gtid->seq_no);
err=
#endif
my_hash_delete(&hash, rec);
DBUG_ASSERT(!err);
}
void
slave_connection_state::remove_if_present(const rpl_gtid *in_gtid)
{
uchar *rec= my_hash_search(&hash, (const uchar *)(&in_gtid->domain_id), 0);
if (rec)
my_hash_delete(&hash, rec);
}
int
slave_connection_state::to_string(String *out_str)
{
out_str->length(0);
return append_to_string(out_str);
}
int
slave_connection_state::append_to_string(String *out_str)
{
uint32 i;
bool first;
first= true;
for (i= 0; i < hash.records; ++i)
{
const entry *e= (const entry *)my_hash_element(&hash, i);
if (rpl_slave_state_tostring_helper(out_str, &e->gtid, &first))
return 1;
}
return 0;
}
int
slave_connection_state::get_gtid_list(rpl_gtid *gtid_list, uint32 list_size)
{
uint32 i, pos;
pos= 0;
for (i= 0; i < hash.records; ++i)
{
entry *e;
if (pos >= list_size)
return 1;
e= (entry *)my_hash_element(&hash, i);
memcpy(&gtid_list[pos++], &e->gtid, sizeof(e->gtid));
}
return 0;
}
/*
Check if the GTID position has been reached, for mysql_binlog_send().
The position has not been reached if we have anything in the state, unless
it has either the START_ON_EMPTY_DOMAIN flag set (which means it does not
belong to this master at all), or the START_OWN_SLAVE_POS (which means that
we start on an old position from when the server was a slave with
--log-slave-updates=0).
*/
bool
slave_connection_state::is_pos_reached()
{
uint32 i;
for (i= 0; i < hash.records; ++i)
{
entry *e= (entry *)my_hash_element(&hash, i);
if (!(e->flags & (START_OWN_SLAVE_POS|START_ON_EMPTY_DOMAIN)))
return false;
}
return true;
}
/*
Execute a MASTER_GTID_WAIT().
The position to wait for is in gtid_str in string form.
The timeout in microseconds is in timeout_us, zero means no timeout.
Returns:
1 for error.
0 for wait completed.
-1 for wait timed out.
*/
int
gtid_waiting::wait_for_pos(THD *thd, String *gtid_str, longlong timeout_us)
{
int err;
rpl_gtid *wait_pos;
uint32 count, i;
struct timespec wait_until, *wait_until_ptr;
ulonglong before;
/* Wait for the empty position returns immediately. */
if (gtid_str->length() == 0)
{
status_var_increment(thd->status_var.master_gtid_wait_count);
return 0;
}
if (!(wait_pos= gtid_parse_string_to_list(gtid_str->ptr(), gtid_str->length(),
&count)))
{
my_error(ER_INCORRECT_GTID_STATE, MYF(0));
return 1;
}
status_var_increment(thd->status_var.master_gtid_wait_count);
before= microsecond_interval_timer();
if (timeout_us >= 0)
{
set_timespec_nsec(wait_until, (ulonglong)1000*timeout_us);
wait_until_ptr= &wait_until;
}
else
wait_until_ptr= NULL;
err= 0;
for (i= 0; i < count; ++i)
{
if ((err= wait_for_gtid(thd, &wait_pos[i], wait_until_ptr)))
break;
}
switch (err)
{
case -1:
status_var_increment(thd->status_var.master_gtid_wait_timeouts);
/* fall through */
case 0:
status_var_add(thd->status_var.master_gtid_wait_time,
static_cast<ulong>
(microsecond_interval_timer() - before));
}
my_free(wait_pos);
return err;
}
void
gtid_waiting::promote_new_waiter(gtid_waiting::hash_element *he)
{
queue_element *qe;
mysql_mutex_assert_owner(&LOCK_gtid_waiting);
if (queue_empty(&he->queue))
return;
qe= (queue_element *)queue_top(&he->queue);
qe->do_small_wait= true;
mysql_cond_signal(&qe->thd->COND_wakeup_ready);
}
void
gtid_waiting::process_wait_hash(uint64 wakeup_seq_no,
gtid_waiting::hash_element *he)
{
mysql_mutex_assert_owner(&LOCK_gtid_waiting);
for (;;)
{
queue_element *qe;
if (queue_empty(&he->queue))
break;
qe= (queue_element *)queue_top(&he->queue);
if (qe->wait_seq_no > wakeup_seq_no)
break;
DBUG_ASSERT(!qe->done);
queue_remove_top(&he->queue);
qe->done= true;;
mysql_cond_signal(&qe->thd->COND_wakeup_ready);
}
}
/*
Execute a MASTER_GTID_WAIT() for one specific domain.
The implementation is optimised primarily for (1) minimal performance impact
on the slave replication threads, and secondarily for (2) quick performance
of MASTER_GTID_WAIT() on a single GTID, which can be useful for consistent
read to clients in an async replication read-scaleout scenario.
To achieve (1), we have a "small" wait and a "large" wait. The small wait
contends with the replication threads on the lock on the gtid_slave_pos, so
only minimal processing is done under that lock, and only a single waiter at
a time does the small wait.
If there is already a small waiter, a new thread will either replace the
small waiter (if it needs to wait for an earlier sequence number), or
instead do a "large" wait.
Once awoken on the small wait, the waiting thread releases the lock shared
with the SQL threads quickly, and then processes all waiters currently doing
the large wait using a different lock that does not impact replication.
This way, the SQL threads only need to do a single check + possibly a
pthread_cond_signal() when updating the gtid_slave_state, and the time that
non-SQL threads contend for the lock on gtid_slave_state is minimized.
There is always at least one thread that has the responsibility to ensure
that there is a small waiter; this thread has queue_element::do_small_wait
set to true. This thread will do the small wait until it is done, at which
point it will make sure to pass on the responsibility to another thread.
Normally only one thread has do_small_wait==true, but it can occasionally
happen that there is more than one, when threads race one another for the
lock on the small wait (this results in slightly increased activity on the
small lock but is otherwise harmless).
Returns:
0 Wait completed normally
-1 Wait completed due to timeout
1 An error (my_error() will have been called to set the error in the da)
*/
int
gtid_waiting::wait_for_gtid(THD *thd, rpl_gtid *wait_gtid,
struct timespec *wait_until)
{
bool timed_out= false;
#ifdef HAVE_REPLICATION
queue_element elem;
uint32 domain_id= wait_gtid->domain_id;
uint64 seq_no= wait_gtid->seq_no;
hash_element *he;
rpl_slave_state::element *slave_state_elem= NULL;
PSI_stage_info old_stage;
bool did_enter_cond= false;
elem.wait_seq_no= seq_no;
elem.thd= thd;
elem.done= false;
mysql_mutex_lock(&LOCK_gtid_waiting);
if (!(he= get_entry(wait_gtid->domain_id)))
{
mysql_mutex_unlock(&LOCK_gtid_waiting);
return 1;
}
/*
If there is already another waiter with seq_no no larger than our own,
we are sure that there is already a small waiter that will wake us up
(or later pass the small wait responsibility to us). So in this case, we
do not need to touch the small wait lock at all.
*/
elem.do_small_wait=
(queue_empty(&he->queue) ||
((queue_element *)queue_top(&he->queue))->wait_seq_no > seq_no);
if (register_in_wait_queue(thd, wait_gtid, he, &elem))
{
mysql_mutex_unlock(&LOCK_gtid_waiting);
return 1;
}
/*
Loop, doing either the small or large wait as appropriate, until either
the position waited for is reached, or we get a kill or timeout.
*/
for (;;)
{
mysql_mutex_assert_owner(&LOCK_gtid_waiting);
if (elem.do_small_wait)
{
uint64 wakeup_seq_no;
queue_element *cur_waiter;
mysql_mutex_lock(&rpl_global_gtid_slave_state->LOCK_slave_state);
/*
The elements in the gtid_slave_state_hash are never re-allocated once
they enter the hash, so we do not need to re-do the lookup after releasing
and re-aquiring the lock.
*/
if (!slave_state_elem &&
!(slave_state_elem= rpl_global_gtid_slave_state->get_element(domain_id)))
{
mysql_mutex_unlock(&rpl_global_gtid_slave_state->LOCK_slave_state);
remove_from_wait_queue(he, &elem);
promote_new_waiter(he);
if (did_enter_cond)
thd->EXIT_COND(&old_stage);
else
mysql_mutex_unlock(&LOCK_gtid_waiting);
my_error(ER_OUT_OF_RESOURCES, MYF(0));
return 1;
}
if ((wakeup_seq_no= slave_state_elem->highest_seq_no) >= seq_no)
{
/*
We do not have to wait. (We will be removed from the wait queue when
we call process_wait_hash() below.
*/
mysql_mutex_unlock(&rpl_global_gtid_slave_state->LOCK_slave_state);
}
else if ((cur_waiter= slave_state_elem->gtid_waiter) &&
slave_state_elem->min_wait_seq_no <= seq_no)
{
/*
There is already a suitable small waiter, go do the large wait.
(Normally we would not have needed to check the small wait in this
case, but it can happen if we race with another thread for the small
lock).
*/
elem.do_small_wait= false;
mysql_mutex_unlock(&rpl_global_gtid_slave_state->LOCK_slave_state);
}
else
{
/*
We have to do the small wait ourselves (stealing it from any thread
that might already be waiting for a later seq_no).
*/
slave_state_elem->gtid_waiter= &elem;
slave_state_elem->min_wait_seq_no= seq_no;
if (cur_waiter)
{
/* We stole the wait, so wake up the old waiting thread. */
mysql_cond_signal(&slave_state_elem->COND_wait_gtid);
}
/* Release the large lock, and do the small wait. */
if (did_enter_cond)
{
thd->EXIT_COND(&old_stage);
did_enter_cond= false;
}
else
mysql_mutex_unlock(&LOCK_gtid_waiting);
thd->ENTER_COND(&slave_state_elem->COND_wait_gtid,
&rpl_global_gtid_slave_state->LOCK_slave_state,
&stage_master_gtid_wait_primary, &old_stage);
do
{
if (unlikely(thd->check_killed(1)))
break;
else if (wait_until)
{
int err=
mysql_cond_timedwait(&slave_state_elem->COND_wait_gtid,
&rpl_global_gtid_slave_state->LOCK_slave_state,
wait_until);
if (err == ETIMEDOUT || err == ETIME)
{
timed_out= true;
break;
}
}
else
mysql_cond_wait(&slave_state_elem->COND_wait_gtid,
&rpl_global_gtid_slave_state->LOCK_slave_state);
} while (slave_state_elem->gtid_waiter == &elem);
wakeup_seq_no= slave_state_elem->highest_seq_no;
/*
If we aborted due to timeout or kill, remove us as waiter.
If we were replaced by another waiter with a smaller seq_no, then we
no longer have responsibility for the small wait.
*/
if ((cur_waiter= slave_state_elem->gtid_waiter))
{
if (cur_waiter == &elem)
slave_state_elem->gtid_waiter= NULL;
else if (slave_state_elem->min_wait_seq_no <= seq_no)
elem.do_small_wait= false;
}
thd->EXIT_COND(&old_stage);
mysql_mutex_lock(&LOCK_gtid_waiting);
}
/*
Note that hash_entry pointers do not change once allocated, so we do
not need to lookup `he' again after re-aquiring LOCK_gtid_waiting.
*/
process_wait_hash(wakeup_seq_no, he);
}
else
{
/* Do the large wait. */
if (!did_enter_cond)
{
thd->ENTER_COND(&thd->COND_wakeup_ready, &LOCK_gtid_waiting,
&stage_master_gtid_wait, &old_stage);
did_enter_cond= true;
}
while (!elem.done && likely(!thd->check_killed(1)))
{
thd_wait_begin(thd, THD_WAIT_BINLOG);
if (wait_until)
{
int err= mysql_cond_timedwait(&thd->COND_wakeup_ready,
&LOCK_gtid_waiting, wait_until);
if (err == ETIMEDOUT || err == ETIME)
timed_out= true;
}
else
mysql_cond_wait(&thd->COND_wakeup_ready, &LOCK_gtid_waiting);
thd_wait_end(thd);
if (elem.do_small_wait || timed_out)
break;
}
}
if ((thd->killed || timed_out) && !elem.done)
{
/* Aborted, so remove ourselves from the hash. */
remove_from_wait_queue(he, &elem);
elem.done= true;
}
if (elem.done)
{
/*
If our wait is done, but we have (or were passed) responsibility for
the small wait, then we need to pass on that task to someone else.
*/
if (elem.do_small_wait)
promote_new_waiter(he);
break;
}
}
if (did_enter_cond)
thd->EXIT_COND(&old_stage);
else
mysql_mutex_unlock(&LOCK_gtid_waiting);
if (thd->killed)
thd->send_kill_message();
#endif /* HAVE_REPLICATION */
return timed_out ? -1 : 0;
}
static void
free_hash_element(void *p)
{
gtid_waiting::hash_element *e= (gtid_waiting::hash_element *)p;
delete_queue(&e->queue);
my_free(e);
}
void
gtid_waiting::init()
{
my_hash_init(PSI_INSTRUMENT_ME, &hash, &my_charset_bin, 32,
offsetof(hash_element, domain_id), sizeof(uint32), NULL,
free_hash_element, HASH_UNIQUE);
mysql_mutex_init(key_LOCK_gtid_waiting, &LOCK_gtid_waiting, 0);
}
void
gtid_waiting::destroy()
{
mysql_mutex_destroy(&LOCK_gtid_waiting);
my_hash_free(&hash);
}
static int
cmp_queue_elem(void *, uchar *a, uchar *b)
{
uint64 seq_no_a= *(uint64 *)a;
uint64 seq_no_b= *(uint64 *)b;
if (seq_no_a < seq_no_b)
return -1;
else if (seq_no_a == seq_no_b)
return 0;
else
return 1;
}
gtid_waiting::hash_element *
gtid_waiting::get_entry(uint32 domain_id)
{
hash_element *e;
if ((e= (hash_element *)my_hash_search(&hash, (const uchar *)&domain_id, 0)))
return e;
if (!(e= (hash_element *)my_malloc(PSI_INSTRUMENT_ME, sizeof(*e), MYF(MY_WME))))
return NULL;
if (init_queue(&e->queue, 8, offsetof(queue_element, wait_seq_no), 0,
cmp_queue_elem, NULL, 1+offsetof(queue_element, queue_idx), 1))
{
my_error(ER_OUT_OF_RESOURCES, MYF(0));
my_free(e);
return NULL;
}
e->domain_id= domain_id;
if (my_hash_insert(&hash, (uchar *)e))
{
my_error(ER_OUT_OF_RESOURCES, MYF(0));
delete_queue(&e->queue);
my_free(e);
return NULL;
}
return e;
}
int
gtid_waiting::register_in_wait_queue(THD *thd, rpl_gtid *wait_gtid,
gtid_waiting::hash_element *he,
gtid_waiting::queue_element *elem)
{
mysql_mutex_assert_owner(&LOCK_gtid_waiting);
if (queue_insert_safe(&he->queue, (uchar *)elem))
{
my_error(ER_OUT_OF_RESOURCES, MYF(0));
return 1;
}
return 0;
}
void
gtid_waiting::remove_from_wait_queue(gtid_waiting::hash_element *he,
gtid_waiting::queue_element *elem)
{
mysql_mutex_assert_owner(&LOCK_gtid_waiting);
queue_remove(&he->queue, elem->queue_idx);
}
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