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MDEV-225: Replace with dummy events an event that is not understood by a slave to which it should be sent

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Add function to replace arbitrary event with dummy event.

Add code which uses this to fix the bug that enabling row_annotate events
on the master breaks slaves which do not request such events.

Add that slaves set a variable @mariadb_slave_capability to inform the
master in a robust way about which events it can, and cannot, handle.

Add tests.
This commit is contained in:
unknown
2012-06-22 11:40:40 +02:00
parent c562c74478
commit 9fe317ffd6
8 changed files with 459 additions and 6 deletions
Download Patch File Download Diff File Expand all files Collapse all files

13
client/mysqlbinlog.cc
View File

@ -1807,6 +1807,19 @@ static Exit_status check_master_version()
"Master returned '%s'", mysql_error(mysql));
goto err;
}
/*
Announce our capabilities to the server, so it will send us all the events
that we know about.
*/
if (mysql_query(mysql, "SET @mariadb_slave_capability="
STRINGIFY_ARG(MARIA_SLAVE_CAPABILITY_MINE)))
{
error("Could not inform master about capability. Master returned '%s'",
mysql_error(mysql));
goto err;
}
delete glob_description_event;
switch (version) {
case 3:

2
mysql-test/include/mtr_warnings.sql
View File

@ -225,6 +225,8 @@ INSERT INTO global_suppressions VALUES
("Slave I/O: The slave I/O thread stops because a fatal error is encountered when it tried to SET @master_binlog_checksum on master.*"),
("Slave I/O: Get master BINLOG_CHECKSUM failed with error.*"),
("Slave I/O: Notifying master by SET @master_binlog_checksum= @@global.binlog_checksum failed with error.*"),
("Slave I/O: Setting master-side filtering of @@skip_replication failed with error:.*"),
("Slave I/O: Setting @mariadb_slave_capability failed with error:.*"),
("THE_LAST_SUPPRESSION")||

98
mysql-test/suite/rpl/r/rpl_mariadb_slave_capability.result Normal file
View File

@ -0,0 +1,98 @@
include/master-slave.inc
[connection master]
set @old_master_binlog_checksum= @@global.binlog_checksum;
set @old_slave_dbug= @@global.debug_dbug;
CREATE TABLE t1 (a INT PRIMARY KEY);
INSERT INTO t1 VALUES (0);
# Test slave with no capability gets dummy event, which is ignored.
include/stop_slave.inc
SET @@global.debug_dbug='+d,simulate_slave_capability_none';
include/start_slave.inc
ALTER TABLE t1 ORDER BY a;
SET SESSION binlog_annotate_row_events = ON;
DELETE FROM t1;
INSERT INTO t1 /* A comment just to make the annotate event sufficiently long that the dummy event will need to get padded with spaces so that we can test that this works */ VALUES(1);
show binlog events in 'master-bin.000001' from <binlog_start> limit 0, 10;
Log_name Pos Event_type Server_id End_log_pos Info
master-bin.000001 # Query # # BEGIN
master-bin.000001 # Annotate_rows # # DELETE FROM t1
master-bin.000001 # Table_map # # table_id: # (test.t1)
master-bin.000001 # Delete_rows # # table_id: # flags: STMT_END_F
master-bin.000001 # Query # # COMMIT
master-bin.000001 # Query # # BEGIN
master-bin.000001 # Annotate_rows # # INSERT INTO t1 /* A comment just to make the annotate event sufficiently long that the dummy event will need to get padded with spaces so that we can test that this works */ VALUES(1)
master-bin.000001 # Table_map # # table_id: # (test.t1)
master-bin.000001 # Write_rows # # table_id: # flags: STMT_END_F
master-bin.000001 # Query # # COMMIT
SELECT * FROM t1;
a
1
show relaylog events in 'slave-relay-bin.000003' from <binlog_start> limit 0,10;
Log_name Pos Event_type Server_id End_log_pos Info
slave-relay-bin.000003 # Query # # BEGIN
slave-relay-bin.000003 # User var # # @`!dummyvar`=NULL
slave-relay-bin.000003 # Table_map # # table_id: # (test.t1)
slave-relay-bin.000003 # Delete_rows # # table_id: # flags: STMT_END_F
slave-relay-bin.000003 # Query # # COMMIT
slave-relay-bin.000003 # Query # # BEGIN
slave-relay-bin.000003 # Query # # # Dummy event replacing event type 160 that slave cannot handle.
slave-relay-bin.000003 # Table_map # # table_id: # (test.t1)
slave-relay-bin.000003 # Write_rows # # table_id: # flags: STMT_END_F
slave-relay-bin.000003 # Query # # COMMIT
set @@global.debug_dbug= @old_slave_dbug;
# Test dummy event is checksummed correctly.
set @@global.binlog_checksum = CRC32;
TRUNCATE t1;
INSERT INTO t1 VALUES(2);
show binlog events in 'master-bin.000002' from <binlog_start> limit 0, 5;
Log_name Pos Event_type Server_id End_log_pos Info
master-bin.000002 # Query # # BEGIN
master-bin.000002 # Annotate_rows # # INSERT INTO t1 VALUES(2)
master-bin.000002 # Table_map # # table_id: # (test.t1)
master-bin.000002 # Write_rows # # table_id: # flags: STMT_END_F
master-bin.000002 # Query # # COMMIT
SELECT * FROM t1;
a
2
show relaylog events in 'slave-relay-bin.000005' from <binlog_start> limit 3,5;
Log_name Pos Event_type Server_id End_log_pos Info
slave-relay-bin.000005 # Query # # BEGIN
slave-relay-bin.000005 # Query # # # Dummy ev
slave-relay-bin.000005 # Table_map # # table_id: # (test.t1)
slave-relay-bin.000005 # Write_rows # # table_id: # flags: STMT_END_F
slave-relay-bin.000005 # Query # # COMMIT
# Test that slave which cannot tolerate holes in binlog stream but
# knows the event does not get dummy event
include/stop_slave.inc
SET @@global.debug_dbug='+d,simulate_slave_capability_old_53';
include/start_slave.inc
ALTER TABLE t1 ORDER BY a;
UPDATE t1 SET a = 3;
show binlog events in 'master-bin.000002' from <binlog_start> limit 0, 5;
Log_name Pos Event_type Server_id End_log_pos Info
master-bin.000002 # Query # # BEGIN
master-bin.000002 # Annotate_rows # # UPDATE t1 SET a = 3
master-bin.000002 # Table_map # # table_id: # (test.t1)
master-bin.000002 # Update_rows # # table_id: # flags: STMT_END_F
master-bin.000002 # Query # # COMMIT
SELECT * FROM t1;
a
3
show relaylog events in 'slave-relay-bin.000006' from <binlog_start> limit 0,5;
Log_name Pos Event_type Server_id End_log_pos Info
slave-relay-bin.000006 # Query # # BEGIN
slave-relay-bin.000006 # Annotate_rows # # UPDATE t1 SET a = 3
slave-relay-bin.000006 # Table_map # # table_id: # (test.t1)
slave-relay-bin.000006 # Update_rows # # table_id: # flags: STMT_END_F
slave-relay-bin.000006 # Query # # COMMIT
select @@global.log_slave_updates;
@@global.log_slave_updates
1
select @@global.replicate_annotate_row_events;
@@global.replicate_annotate_row_events
0
set @@global.debug_dbug= @old_slave_dbug;
Clean up.
set @@global.binlog_checksum = @old_master_binlog_checksum;
DROP TABLE t1;
include/rpl_end.inc

104
mysql-test/suite/rpl/t/rpl_mariadb_slave_capability.test Normal file
View File

@ -0,0 +1,104 @@
--source include/master-slave.inc
--source include/have_debug.inc
--source include/have_binlog_format_row.inc
connection master;
set @old_master_binlog_checksum= @@global.binlog_checksum;
set @old_slave_dbug= @@global.debug_dbug;
CREATE TABLE t1 (a INT PRIMARY KEY);
INSERT INTO t1 VALUES (0);
sync_slave_with_master;
connection slave;
--echo # Test slave with no capability gets dummy event, which is ignored.
--source include/stop_slave.inc
SET @@global.debug_dbug='+d,simulate_slave_capability_none';
--source include/start_slave.inc
connection master;
# Add a dummy event just to have something to sync_slave_with_master on.
# Otherwise we occasionally get different $relaylog_start, depending on
# whether Format_description_log_event was written to relay log or not
# at the time of SHOW SLAVE STATUS.
ALTER TABLE t1 ORDER BY a;
sync_slave_with_master;
connection slave;
let $relaylog_start= query_get_value(SHOW SLAVE STATUS, Relay_Log_Pos, 1);
connection master;
SET SESSION binlog_annotate_row_events = ON;
let $binlog_file= query_get_value(SHOW MASTER STATUS, File, 1);
let $binlog_start= query_get_value(SHOW MASTER STATUS, Position, 1);
# A short event, to test when we need to use user_var_event for dummy event.
DELETE FROM t1;
INSERT INTO t1 /* A comment just to make the annotate event sufficiently long that the dummy event will need to get padded with spaces so that we can test that this works */ VALUES(1);
let $binlog_limit= 0, 10;
--source include/show_binlog_events.inc
sync_slave_with_master;
connection slave;
SELECT * FROM t1;
let $binlog_file= query_get_value(SHOW SLAVE STATUS, Relay_Log_File, 1);
let $binlog_start= $relaylog_start;
let $binlog_limit=0,10;
--source include/show_relaylog_events.inc
set @@global.debug_dbug= @old_slave_dbug;
--echo # Test dummy event is checksummed correctly.
connection master;
set @@global.binlog_checksum = CRC32;
TRUNCATE t1;
let $binlog_file= query_get_value(SHOW MASTER STATUS, File, 1);
let $binlog_start= query_get_value(SHOW MASTER STATUS, Position, 1);
INSERT INTO t1 VALUES(2);
let $binlog_limit= 0, 5;
--source include/show_binlog_events.inc
sync_slave_with_master;
connection slave;
SELECT * FROM t1;
let $binlog_file= query_get_value(SHOW SLAVE STATUS, Relay_Log_File, 1);
let $binlog_start= 0;
let $binlog_limit=3,5;
--source include/show_relaylog_events.inc
--echo # Test that slave which cannot tolerate holes in binlog stream but
--echo # knows the event does not get dummy event
--source include/stop_slave.inc
SET @@global.debug_dbug='+d,simulate_slave_capability_old_53';
--source include/start_slave.inc
connection master;
ALTER TABLE t1 ORDER BY a;
sync_slave_with_master;
connection slave;
let $relaylog_start= query_get_value(SHOW SLAVE STATUS, Relay_Log_Pos, 1);
connection master;
let $binlog_file= query_get_value(SHOW MASTER STATUS, File, 1);
let $binlog_start= query_get_value(SHOW MASTER STATUS, Position, 1);
UPDATE t1 SET a = 3;
let $binlog_limit= 0, 5;
--source include/show_binlog_events.inc
sync_slave_with_master;
connection slave;
SELECT * FROM t1;
let $binlog_file= query_get_value(SHOW SLAVE STATUS, Relay_Log_File, 1);
let $binlog_start= $relaylog_start;
let $binlog_limit=0,5;
--source include/show_relaylog_events.inc
select @@global.log_slave_updates;
select @@global.replicate_annotate_row_events;
set @@global.debug_dbug= @old_slave_dbug;
--echo Clean up.
connection master;
set @@global.binlog_checksum = @old_master_binlog_checksum;
DROP TABLE t1;
sync_slave_with_master;
--source include/rpl_end.inc

109
sql/log_event.cc
View File

@ -3300,6 +3300,115 @@ Query_log_event::Query_log_event(const char* buf, uint event_len,
}
/*
Replace a binlog event read into a packet with a dummy event. Either a
Query_log_event that has just a comment, or if that will not fit in the
space used for the event to be replaced, then a NULL user_var event.
This is used when sending binlog data to a slave which does not understand
this particular event and which is too old to support informational events
or holes in the event stream.
This allows to write such events into the binlog on the master and still be
able to replicate against old slaves without them breaking.
Clears the flag LOG_EVENT_THREAD_SPECIFIC_F and set LOG_EVENT_SUPPRESS_USE_F.
Overwrites the type with QUERY_EVENT (or USER_VAR_EVENT), and replaces the
body with a minimal query / NULL user var.
Returns zero on success, -1 if error due to too little space in original
event. A minimum of 25 bytes (19 bytes fixed header + 6 bytes in the body)
is needed in any event to be replaced with a dummy event.
*/
int
Query_log_event::dummy_event(String *packet, ulong ev_offset,
uint8 checksum_alg)
{
uchar *p= (uchar *)packet->ptr() + ev_offset;
size_t data_len= packet->length() - ev_offset;
uint16 flags;
static const size_t min_user_var_event_len=
LOG_EVENT_HEADER_LEN + UV_NAME_LEN_SIZE + 1 + UV_VAL_IS_NULL; // 25
static const size_t min_query_event_len=
LOG_EVENT_HEADER_LEN + QUERY_HEADER_LEN + 1 + 1; // 34
if (checksum_alg == BINLOG_CHECKSUM_ALG_CRC32)
data_len-= BINLOG_CHECKSUM_LEN;
else
DBUG_ASSERT(checksum_alg == BINLOG_CHECKSUM_ALG_UNDEF ||
checksum_alg == BINLOG_CHECKSUM_ALG_OFF);
if (data_len < min_user_var_event_len)
/* Cannot replace with dummy, event too short. */
return -1;
flags= uint2korr(p + FLAGS_OFFSET);
flags&= ~LOG_EVENT_THREAD_SPECIFIC_F;
flags|= LOG_EVENT_SUPPRESS_USE_F;
int2store(p + FLAGS_OFFSET, flags);
if (data_len < min_query_event_len)
{
/*
Have to use dummy user_var event for such a short packet.
This works, but the event will be considered part of an event group with
the following event. So for example @@global.sql_slave_skip_counter=1
will skip not only the dummy event, but also the immediately following
event.
We write a NULL user var with the name @`!dummyvar` (or as much
as that as will fit within the size of the original event - so
possibly just @`!`).
*/
static const char var_name[]= "!dummyvar";
uint name_len= data_len - (min_user_var_event_len - 1);
p[EVENT_TYPE_OFFSET]= USER_VAR_EVENT;
int4store(p + LOG_EVENT_HEADER_LEN, name_len);
memcpy(p + LOG_EVENT_HEADER_LEN + UV_NAME_LEN_SIZE, var_name, name_len);
p[LOG_EVENT_HEADER_LEN + UV_NAME_LEN_SIZE + name_len]= 1; // indicates NULL
}
else
{
/*
Use a dummy query event, just a comment.
*/
static const char message[]=
"# Dummy event replacing event type %u that slave cannot handle.";
char buf[sizeof(message)+1]; /* +1, as %u can expand to 3 digits. */
uchar old_type= p[EVENT_TYPE_OFFSET];
uchar *q= p + LOG_EVENT_HEADER_LEN;
size_t comment_len, len;
p[EVENT_TYPE_OFFSET]= QUERY_EVENT;
int4store(q + Q_THREAD_ID_OFFSET, 0);
int4store(q + Q_EXEC_TIME_OFFSET, 0);
q[Q_DB_LEN_OFFSET]= 0;
int2store(q + Q_ERR_CODE_OFFSET, 0);
int2store(q + Q_STATUS_VARS_LEN_OFFSET, 0);
q[Q_DATA_OFFSET]= 0; /* Zero terminator for empty db */
q+= Q_DATA_OFFSET + 1;
len= my_snprintf(buf, sizeof(buf), message, old_type);
comment_len= data_len - (min_query_event_len - 1);
if (comment_len <= len)
memcpy(q, buf, comment_len);
else
{
memcpy(q, buf, len);
memset(q+len, ' ', comment_len - len);
}
}
if (checksum_alg == BINLOG_CHECKSUM_ALG_CRC32)
{
ha_checksum crc= my_checksum(0L, p, data_len);
int4store(p + data_len, crc);
}
return 0;
}
#ifdef MYSQL_CLIENT
/**
Query_log_event::print().

38
sql/log_event.h
View File

@ -573,6 +573,43 @@ enum enum_binlog_checksum_alg {
#define BINLOG_CHECKSUM_LEN CHECKSUM_CRC32_SIGNATURE_LEN
#define BINLOG_CHECKSUM_ALG_DESC_LEN 1 /* 1 byte checksum alg descriptor */
/*
These are capability numbers for MariaDB slave servers.
Newer MariaDB slaves set this to inform the master about their capabilities.
This allows the master to decide which events it can send to the slave
without breaking replication on old slaves that maybe do not understand
all events from newer masters.
As new releases are backwards compatible, a given capability implies also
all capabilities with smaller number.
Older MariaDB slaves and other MySQL slave servers do not set this, so they
are recorded with capability 0.
*/
/* MySQL or old MariaDB slave with no announced capability. */
#define MARIA_SLAVE_CAPABILITY_UNKNOWN 0
/* MariaDB >= 5.3, which understands ANNOTATE_ROWS_EVENT. */
#define MARIA_SLAVE_CAPABILITY_ANNOTATE 1
/*
MariaDB >= 5.5. This version has the capability to tolerate events omitted
from the binlog stream without breaking replication (MySQL slaves fail
because they mis-compute the offsets into the master's binlog).
*/
#define MARIA_SLAVE_CAPABILITY_TOLERATE_HOLES 2
/* MariaDB > 5.5, which knows about binlog_checkpoint_log_event. */
#define MARIA_SLAVE_CAPABILITY_BINLOG_CHECKPOINT 3
/*
MariaDB server which understands MySQL 5.6 ignorable events. This server
can tolerate receiving any event with the LOG_EVENT_IGNORABLE_F flag set.
*/
#define MARIA_SLAVE_CAPABILITY_IGNORABLE 4
/* Our capability. */
#define MARIA_SLAVE_CAPABILITY_MINE MARIA_SLAVE_CAPABILITY_BINLOG_CHECKPOINT
/**
@enum Log_event_type
@ -1827,6 +1864,7 @@ public:
my_free(data_buf);
}
Log_event_type get_type_code() { return QUERY_EVENT; }
static int dummy_event(String *packet, ulong ev_offset, uint8 checksum_alg);
#ifdef MYSQL_SERVER
bool write(IO_CACHE* file);
virtual bool write_post_header_for_derived(IO_CACHE* file) { return FALSE; }

32
sql/slave.cc
View File

@ -1753,6 +1753,38 @@ past_checksum:
}
}
}
/* Announce MariaDB slave capabilities. */
DBUG_EXECUTE_IF("simulate_slave_capability_none", goto after_set_capability;);
{
const char *q=
DBUG_EVALUATE_IF("simulate_slave_capability_old_53",
"SET @mariadb_slave_capability="
STRINGIFY_ARG(MARIA_SLAVE_CAPABILITY_ANNOTATE),
"SET @mariadb_slave_capability="
STRINGIFY_ARG(MARIA_SLAVE_CAPABILITY_MINE));
if (mysql_real_query(mysql, q, strlen(q)))
{
err_code= mysql_errno(mysql);
if (is_network_error(err_code))
{
mi->report(ERROR_LEVEL, err_code,
"Setting @mariadb_slave_capability failed with error: %s",
mysql_error(mysql));
goto network_err;
}
else
{
/* Fatal error */
errmsg= "The slave I/O thread stops because a fatal error is "
"encountered when it tries to set @mariadb_slave_capability.";
sprintf(err_buff, "%s Error: %s", errmsg, mysql_error(mysql));
goto err;
}
}
}
after_set_capability:
err:
if (errmsg)
{

69
sql/sql_repl.cc
View File

@ -491,6 +491,27 @@ static ulonglong get_heartbeat_period(THD * thd)
return entry? entry->val_int(&null_value) : 0;
}
/*
Lookup the capabilities of the slave, which it announces by setting a value
MARIA_SLAVE_CAPABILITY_XXX in @mariadb_slave_capability.
Older MariaDB slaves, and other MySQL slaves, do not set
@mariadb_slave_capability, corresponding to a capability of
MARIA_SLAVE_CAPABILITY_UNKNOWN (0).
*/
static int
get_mariadb_slave_capability(THD *thd)
{
bool null_value;
const LEX_STRING name= { C_STRING_WITH_LEN("mariadb_slave_capability") };
const user_var_entry *entry=
(user_var_entry*) my_hash_search(&thd->user_vars, (uchar*) name.str,
name.length);
return entry ?
(int)(entry->val_int(&null_value)) : MARIA_SLAVE_CAPABILITY_UNKNOWN;
}
/*
Function prepares and sends repliation heartbeat event.
@ -563,14 +584,44 @@ static int send_heartbeat_event(NET* net, String* packet,
static const char *
send_event_to_slave(THD *thd, NET *net, String* const packet, ushort flags,
Log_event_type event_type, char *log_file_name,
IO_CACHE *log)
IO_CACHE *log, int mariadb_slave_capability,
ulong ev_offset, uint8 current_checksum_alg)
{
my_off_t pos;
/* Do not send annotate_rows events unless slave requested it. */
if (event_type == ANNOTATE_ROWS_EVENT &&
!(flags & BINLOG_SEND_ANNOTATE_ROWS_EVENT))
return NULL;
if (event_type == ANNOTATE_ROWS_EVENT && !(flags & BINLOG_SEND_ANNOTATE_ROWS_EVENT))
{
if (mariadb_slave_capability >= MARIA_SLAVE_CAPABILITY_TOLERATE_HOLES)
{
/* This slave can tolerate events omitted from the binlog stream. */
return NULL;
}
else if (mariadb_slave_capability >= MARIA_SLAVE_CAPABILITY_ANNOTATE)
{
/*
The slave did not request ANNOTATE_ROWS_EVENT (it does not need them as
it will not log them in its own binary log). However, it understands the
event and will just ignore it, and it would break if we omitted it,
leaving a hole in the binlog stream. So just send the event as-is.
*/
}
else
{
/*
The slave does not understand ANNOTATE_ROWS_EVENT.
Older MariaDB slaves (and MySQL slaves) will break replication if there
are holes in the binlog stream (they will miscompute the binlog offset
and request the wrong position when reconnecting).
So replace the event with a dummy event of the same size that will be
a no-operation on the slave.
*/
if (Query_log_event::dummy_event(packet, ev_offset, current_checksum_alg))
return "Failed to replace row annotate event with dummy: too small event.";
}
}
/*
Skip events with the @@skip_replication flag set, if slave requested
@ -628,6 +679,7 @@ void mysql_binlog_send(THD* thd, char* log_ident, my_off_t pos,
NET* net = &thd->net;
mysql_mutex_t *log_lock;
mysql_cond_t *log_cond;
int mariadb_slave_capability;
uint8 current_checksum_alg= BINLOG_CHECKSUM_ALG_UNDEF;
int old_max_allowed_packet= thd->variables.max_allowed_packet;
@ -653,6 +705,7 @@ void mysql_binlog_send(THD* thd, char* log_ident, my_off_t pos,
heartbeat_ts= &heartbeat_buf;
set_timespec_nsec(*heartbeat_ts, 0);
}
mariadb_slave_capability= get_mariadb_slave_capability(thd);
if (global_system_variables.log_warnings > 1)
sql_print_information("Start binlog_dump to slave_server(%d), pos(%s, %lu)",
thd->server_id, log_ident, (ulong)pos);
@ -939,7 +992,9 @@ impossible position";
}
if ((tmp_msg= send_event_to_slave(thd, net, packet, flags, event_type,
log_file_name, &log)))
log_file_name, &log,
mariadb_slave_capability, ev_offset,
current_checksum_alg)))
{
errmsg= tmp_msg;
my_errno= ER_UNKNOWN_ERROR;
@ -1097,7 +1152,9 @@ impossible position";
if (read_packet &&
(tmp_msg= send_event_to_slave(thd, net, packet, flags, event_type,
log_file_name, &log)))
log_file_name, &log,
mariadb_slave_capability, ev_offset,
current_checksum_alg)))
{
errmsg= tmp_msg;
my_errno= ER_UNKNOWN_ERROR;