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An IGNORABLE event is added into binlog when a gap between two events is detected

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An IGNORABLE event is added into binlog when a gap between two events
is detected.

New routines create and write special events.

Special events are not sent to slaves.
This commit is contained in:
MassimilianoPinto
2016-09-16 14:55:37 +02:00
parent 8e5fa51efa
commit 26f87c2bd8
2 changed files with 198 additions and 1 deletions
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187
server/modules/routing/binlog/blr_file.c
View File

@ -35,6 +35,8 @@
* 23/10/2015 Markus Makela Added current_safe_event
* 26/04/2016 Massimiliano Pinto Added MariaDB 10.0 and 10.1 GTID event flags detection
* 11/07/2016 Massimiliano Pinto Added SSL backend support
* 16/09/2016 Massimiliano Pinto Addition of IGNORABLE_EVENT in case of a missing event
* detected from master binlog stream
*
* @endverbatim
*/
@ -70,6 +72,7 @@ int blr_file_write_master_config(ROUTER_INSTANCE *router, char *error);
extern uint32_t extract_field(uint8_t *src, int bits);
static void blr_format_event_size(double *event_size, char *label);
extern int MaxScaleUptime();
extern void encode_value(unsigned char *data, unsigned int value, int len);
typedef struct binlog_event_desc
{
@ -81,6 +84,22 @@ typedef struct binlog_event_desc
static void blr_print_binlog_details(ROUTER_INSTANCE *router,
BINLOG_EVENT_DESC first_event_time,
BINLOG_EVENT_DESC last_event_time);
static uint8_t *blr_create_ignorable_event(uint32_t event_size,
REP_HEADER *hdr,
uint32_t event_pos,
bool do_checksum);
static int blr_write_special_event(ROUTER_INSTANCE *router,
uint32_t file_offset,
uint32_t hole_size,
REP_HEADER *hdr,
int type);
/** MaxScale generated events */
typedef enum
{
BLRM_IGNORABLE, /*< Ignorable event */
BLRM_START_ENCRYPTION /*< Start Encryption event */
} generated_event_t;
/**
* Initialise the binlog file for this instance. MaxScale will look
@ -363,7 +382,24 @@ int
blr_write_binlog_record(ROUTER_INSTANCE *router, REP_HEADER *hdr, uint32_t size, uint8_t *buf)
{
int n;
uint64_t file_offset = router->current_pos;
/**
* Check for possible hole looking at curren pos and next pos
* Fill the gap with a self generated ignorable event
* Binlog file position is incremented by blr_write_special_event()
*/
if (hdr->next_pos && (hdr->next_pos > (file_offset + size)))
{
uint64_t hole_size = hdr->next_pos - file_offset - size;
if (!blr_write_special_event(router, file_offset, hole_size, hdr, BLRM_IGNORABLE))
{
return 0;
}
}
/* Write current received event form master */
if ((n = pwrite(router->binlog_fd, buf, size,
router->last_written)) != size)
{
@ -383,11 +419,14 @@ blr_write_binlog_record(ROUTER_INSTANCE *router, REP_HEADER *hdr, uint32_t size,
}
return 0;
}
// Increment offsets
spinlock_acquire(&router->binlog_lock);
router->current_pos = hdr->next_pos;
router->last_written += size;
router->last_event_pos = hdr->next_pos - hdr->event_size;
spinlock_release(&router->binlog_lock);
return n;
}
@ -1994,7 +2033,7 @@ blr_file_write_master_config(ROUTER_INSTANCE *router, char *error)
/** Print Binlog Details
*
* @param router The router instance
* @param router The router instance
* @param first_event First Event details
* @param last_event First Event details
*/
@ -2039,3 +2078,149 @@ blr_print_binlog_details(ROUTER_INSTANCE *router,
event_desc != NULL ? event_desc : "unknown", buf_t);
}
/** Create an ignorable event
*
* @param event_size The size of the new event being created (crc32 4 bytes could be included)
* @param hdr Current replication event header, received form master
* @param event_pos The position in binlog file of the new event
* @param do_checksum Whether checksum must be calculated and stored
* @return Returns the pointer of new event
*/
static uint8_t *
blr_create_ignorable_event(uint32_t event_size,
REP_HEADER *hdr,
uint32_t event_pos,
bool do_checksum)
{
uint8_t *new_event;
if (event_size < BINLOG_EVENT_HDR_LEN)
{
MXS_ERROR("blr_create_ignorable_event an event of %lu bytes"
" is not valid in blr_file.c", (unsigned long)event_size);
return NULL;
}
// Allocate space for event: size might contain the 4 crc32
new_event = MXS_CALLOC(1, event_size);
if (new_event == NULL)
{
MXS_ERROR("Unable to allocate memory for blr_create_ignorable_event in blr_file.c ");
return NULL;
}
// Populate Event header 19 bytes for Ignorable Event
encode_value(&new_event[0], hdr->timestamp, 32); // same timestamp as in current received event
new_event[4] = IGNORABLE_EVENT; // type is IGNORABLE_EVENT
encode_value(&new_event[5], hdr->serverid, 32); // same serverid as in current received event
encode_value(&new_event[9], event_size, 32); // event size
encode_value(&new_event[13], event_pos + event_size, 32); // next_pos
encode_value(&new_event[17], LOG_EVENT_IGNORABLE_F, 16); // flag is LOG_EVENT_IGNORABLE_F
/* if checksum is required calculate the crc32 and add it in the last 4 bytes*/
if (do_checksum)
{
/*
* Now add the CRC to the Ignorable binlog event.
*
* The algorithm is first to compute the checksum of an empty buffer
* and then the checksum of the real event: 4 byte less than event_size
*/
uint32_t chksum;
chksum = crc32(0L, NULL, 0);
chksum = crc32(chksum, new_event, event_size - 4);
// checksum is stored after current event data using 4 bytes
encode_value(new_event + event_size - 4, chksum, 32);
}
return new_event;
}
/**
* Create and write a special event (not received form master) into binlog file
*
* @param router The current router instance
* @param file_offset Position where event will be written
* @param event_size The size of new event (it might hold the 4 bytes crc32)
* @param hdr Replication header of the current reived event (from Master)
* @param type Type of special event to create and write
*/
static int
blr_write_special_event(ROUTER_INSTANCE *router, uint32_t file_offset, uint32_t event_size, REP_HEADER *hdr, int type)
{
int n;
uint8_t *new_event;
char *new_event_desc;
switch (type)
{
case BLRM_IGNORABLE:
new_event_desc = "IGNORABLE";
MXS_INFO("Hole detected while writing in binlog '%s' @ %lu: an %s event "
"of %lu bytes will be written at pos %lu",
router->binlog_name,
router->current_pos,
new_event_desc,
(unsigned long)event_size,
(unsigned long)file_offset);
/* Create new Ignorable event */
if ((new_event = blr_create_ignorable_event(event_size,
hdr,
file_offset,
router->master_chksum)) == NULL)
{
return 0;
}
break;
default:
new_event_desc = "UNKNOWN";
MXS_ERROR("Cannot create special binlog event of %s type and size %lu "
"in binlog file '%s' @ %lu",
new_event_desc,
(unsigned long)event_size,
router->binlog_name,
router->current_pos);
new_event_desc = "UNKNOWN";
return 0;
break;
}
// Write the event
if ((n = pwrite(router->binlog_fd, new_event, event_size, file_offset)) != event_size)
{
char err_msg[STRERROR_BUFLEN];
MXS_ERROR("%s: Failed to write %s special binlog record at %lu of %s, %s. "
"Truncating to previous record.",
router->service->name, new_event_desc, (unsigned long)file_offset,
router->binlog_name,
strerror_r(errno, err_msg, sizeof(err_msg)));
/* Remove any partial event that was written */
if (ftruncate(router->binlog_fd, router->last_written))
{
MXS_ERROR("%s: Failed to truncate %s special binlog record at %lu of %s, %s. ",
router->service->name, new_event_desc, (unsigned long)file_offset,
router->binlog_name,
strerror_r(errno, err_msg, sizeof(err_msg)));
}
MXS_FREE(new_event);
return 0;
}
MXS_FREE(new_event);
// Increment offsets, next event will be written after this special one
spinlock_acquire(&router->binlog_lock);
router->last_written += event_size;
router->current_pos = file_offset + event_size;
router->last_event_pos = file_offset;
spinlock_release(&router->binlog_lock);
// Force write
fsync(router->binlog_fd);
return 1;
}