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MDEV-40236: Generalize --flashback error messages for non-flashback #5454

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df37bef
MDEV-20749 Improve mysqlbinlog --flashback error reporting
monthdev Mar 9, 2026
0200fd9
MDEV-40236: Generalize `--flashback` error messages for non-flashback
ParadoxV5 Jul 25, 2026
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16 changes: 14 additions & 2 deletions client/mysqlbinlog.cc
View file
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Original file line number Diff line number Diff line change
Expand Up @@ -897,17 +897,21 @@ static bool print_row_event(PRINT_EVENT_INFO *print_event_info, Log_event *ev,
for (size_t i= events_in_stmt.elements; i > 0; --i)
{
e= *(dynamic_element(&events_in_stmt, i - 1, Log_event**));
result= result || print_base64(print_event_info, e);
if ((result= print_base64(print_event_info, e)))
break;
}
// Copy all output into the Log_event
ev->output_buf.copy(e->output_buf);
if (!result)
ev->output_buf.copy(e->output_buf);
// Delete Log_event
for (size_t i= 0; i < events_in_stmt.elements-1; ++i)
{
e= *(dynamic_element(&events_in_stmt, i, Log_event**));
delete e;
}
reset_dynamic(&events_in_stmt);
if (result)
return result;
}
}

Expand Down Expand Up @@ -1956,6 +1960,14 @@ static void cleanup()
mysql_server_end();
if (opt_flashback)
{
if (binlog_events.buffer)
{
for (size_t i= 0; i < binlog_events.elements; ++i)
{
LEX_STRING *event_str= dynamic_element(&binlog_events, i, LEX_STRING*);
my_free(event_str->str);
}
}
delete_dynamic(&binlog_events);
delete_dynamic(&events_in_stmt);
}
Expand Down
16 changes: 16 additions & 0 deletions mysql-test/suite/rpl/r/mdev_20749_bad_field_length.result
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Original file line number Diff line number Diff line change
@@ -0,0 +1,16 @@
#
# MDEV-20749 corrupted BLOB metadata should report bad field length
# The server-side DBUG hook corrupts the BLOB metadata written in
# the table map event so mariadb-binlog --flashback cannot determine the
# field length while decoding the row image.
#
create table t1 (a int, b blob) engine=innodb;
set @old_dbug= @@debug_dbug;
set debug_dbug= "+d,flashback_corrupt_blob_metadata";
insert into t1 values (1, repeat("a",3104));
set debug_dbug= @old_dbug;
flush binary logs;
# MYSQL_BINLOG --result-file=RESULT_FILE -vvv --flashback MYSQLD_DATADIR/BINLOG_FILE 2>&1

Error decoding row image (could not determine field length): event=Delete_rows_v1, column=1, column_type=252, metadata=5
DROP TABLE t1;
17 changes: 17 additions & 0 deletions mysql-test/suite/rpl/r/mdev_20749_truncated.result
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Original file line number Diff line number Diff line change
@@ -0,0 +1,17 @@
#
# MDEV-20749 corrupted BLOB length prefix should report truncated row image
# The server-side DBUG hook corrupts the serialized row image written to
# the binary log by increasing the BLOB length prefix without changing
# the event size. mariadb-binlog --flashback should then report that the
# field extends past the row buffer while decoding the WRITE_ROWS_EVENT.
#
create table t1 (a int, b blob) engine=innodb;
set @old_dbug= @@debug_dbug;
set debug_dbug= "+d,flashback_corrupt_blob_length_prefix";
insert into t1 values (1, repeat("a",3104));
set debug_dbug= @old_dbug;
flush binary logs;
# MYSQL_BINLOG --result-file=RESULT_FILE -vvv --flashback MYSQLD_DATADIR/BINLOG_FILE 2>&1

Error decoding row image (field extends past row buffer): event=Delete_rows_v1, column=1
DROP TABLE t1;
27 changes: 27 additions & 0 deletions mysql-test/suite/rpl/t/mdev_20749_bad_field_length.test
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Original file line number Diff line number Diff line change
@@ -0,0 +1,27 @@
--echo #
--echo # MDEV-20749 corrupted BLOB metadata should report bad field length
--echo # The server-side DBUG hook corrupts the BLOB metadata written in
--echo # the table map event so mariadb-binlog --flashback cannot determine the
--echo # field length while decoding the row image.
--echo #

--source include/have_innodb.inc
--source include/have_binlog_format_row.inc
--source include/have_debug.inc

create table t1 (a int, b blob) engine=innodb;

set @old_dbug= @@debug_dbug;
set debug_dbug= "+d,flashback_corrupt_blob_metadata";
insert into t1 values (1, repeat("a",3104));
set debug_dbug= @old_dbug;

--let $MYSQLD_DATADIR= `select @@datadir`
--let $BINLOG_FILE= query_get_value(SHOW MASTER STATUS, File, 1)
flush binary logs;
--let $RESULT_FILE= $MYSQLTEST_VARDIR/tmp/mariadb_binlog_out.sql
--echo # MYSQL_BINLOG --result-file=RESULT_FILE -vvv --flashback MYSQLD_DATADIR/BINLOG_FILE 2>&1
--error 1
--exec $MYSQL_BINLOG --result-file=$RESULT_FILE -vvv --flashback $MYSQLD_DATADIR/$BINLOG_FILE 2>&1

DROP TABLE t1;
28 changes: 28 additions & 0 deletions mysql-test/suite/rpl/t/mdev_20749_truncated.test
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Original file line number Diff line number Diff line change
@@ -0,0 +1,28 @@
--echo #
--echo # MDEV-20749 corrupted BLOB length prefix should report truncated row image
--echo # The server-side DBUG hook corrupts the serialized row image written to
--echo # the binary log by increasing the BLOB length prefix without changing
--echo # the event size. mariadb-binlog --flashback should then report that the
--echo # field extends past the row buffer while decoding the WRITE_ROWS_EVENT.
--echo #

--source include/have_innodb.inc
--source include/have_binlog_format_row.inc
--source include/have_debug.inc

create table t1 (a int, b blob) engine=innodb;

set @old_dbug= @@debug_dbug;
set debug_dbug= "+d,flashback_corrupt_blob_length_prefix";
insert into t1 values (1, repeat("a",3104));
set debug_dbug= @old_dbug;

--let $MYSQLD_DATADIR= `select @@datadir`
--let $BINLOG_FILE= query_get_value(SHOW MASTER STATUS, File, 1)
flush binary logs;
--let $RESULT_FILE= $MYSQLTEST_VARDIR/tmp/mariadb_binlog_out.sql
--echo # MYSQL_BINLOG --result-file=RESULT_FILE -vvv --flashback MYSQLD_DATADIR/BINLOG_FILE 2>&1
--error 1
--exec $MYSQL_BINLOG --result-file=$RESULT_FILE -vvv --flashback $MYSQLD_DATADIR/$BINLOG_FILE 2>&1

DROP TABLE t1;
8 changes: 3 additions & 5 deletions sql/log_event.h
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Original file line number Diff line number Diff line change
Expand Up @@ -4824,17 +4824,15 @@ class Rows_log_event : public Log_event

/* not for direct call, each derived has its own ::print() */
bool print(FILE *file, PRINT_EVENT_INFO *print_event_info) override= 0;
void change_to_flashback_event(PRINT_EVENT_INFO *print_event_info, uchar *rows_buff, Log_event_type ev_type);
bool change_to_flashback_event(PRINT_EVENT_INFO *print_event_info, uchar *rows_buff, Log_event_type ev_type);
bool print_verbose(IO_CACHE *file,
PRINT_EVENT_INFO *print_event_info);
size_t print_verbose_one_row(IO_CACHE *file, table_def *td,
PRINT_EVENT_INFO *print_event_info,
MY_BITMAP *cols_bitmap,
const uchar *ptr, const uchar *prefix);
size_t calc_row_event_length(table_def *td,
MY_BITMAP *cols_bitmap,
const uchar *value,
Field_info *fields);
size_t calc_row_event_length(table_def *td, MY_BITMAP *cols_bitmap,
const uchar *value, Field_info *fields);
void count_row_events(PRINT_EVENT_INFO *print_event_info);

#endif
Expand Down
94 changes: 65 additions & 29 deletions sql/log_event_client.cc
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -1124,7 +1124,7 @@ static uchar *fill_row_image(const MY_BITMAP *cols_bitmap,
@param[in] rows_buff Packed event buff
*/

void Rows_log_event::change_to_flashback_event(PRINT_EVENT_INFO *print_event_info,
bool Rows_log_event::change_to_flashback_event(PRINT_EVENT_INFO *print_event_info,
uchar *rows_buff, Log_event_type ev_type)
{
Table_map_log_event *map;
Expand All @@ -1133,16 +1133,24 @@ void Rows_log_event::change_to_flashback_event(PRINT_EVENT_INFO *print_event_inf
uchar *rows_pos= rows_buff + m_rows_before_size;
Field_info *ai_fields= nullptr;
Field_info *bi_fields= nullptr;
bool error= false;

if (!(map= print_event_info->m_table_map.get_table(m_table_id)) ||
!(td= map->create_table_def()))
return;
return false;

/* If the write rows event contained no values for the AI */
if (((get_general_type_code() == WRITE_ROWS_EVENT) && (m_rows_buf==m_rows_end)))
goto end;
goto err;

(void) my_init_dynamic_array(PSI_NOT_INSTRUMENTED, &rows_arr, sizeof(LEX_STRING), 8, 8, MYF(0));
if (my_init_dynamic_array(PSI_NOT_INSTRUMENTED, &rows_arr,
sizeof(LEX_STRING), 8, 8, MYF(0)))
{
fprintf(stderr, "\nError: Out of memory. "
"Could not exchange to flashback event.\n");
error= true;
goto err;
}

if (get_general_type_code() == UPDATE_ROWS_EVENT ||
get_general_type_code() == UPDATE_ROWS_EVENT_V1)
Expand All @@ -1159,7 +1167,8 @@ void Rows_log_event::change_to_flashback_event(PRINT_EVENT_INFO *print_event_inf
{
fprintf(stderr, "\nError: Out of memory. "
"Could not exchange to flashback event.\n");
exit(1);
error= true;
goto end;
}
}
}
Expand All @@ -1170,8 +1179,8 @@ void Rows_log_event::change_to_flashback_event(PRINT_EVENT_INFO *print_event_inf
size_t length1= 0;
if (!(length1= calc_row_event_length(td, &m_cols, value, bi_fields)))
{
fprintf(stderr, "\nError row length: %zu\n", length1);
exit(1);
error= true;
goto end;
}
value+= length1;

Expand All @@ -1182,8 +1191,8 @@ void Rows_log_event::change_to_flashback_event(PRINT_EVENT_INFO *print_event_inf
{
if (!(length2= calc_row_event_length(td, &m_cols_ai, value, ai_fields)))
{
fprintf(stderr, "\nError row length: %zu\n", length2);
exit(1);
error= true;
goto end;
}
value+= length2;
}
Expand All @@ -1197,7 +1206,8 @@ void Rows_log_event::change_to_flashback_event(PRINT_EVENT_INFO *print_event_inf
{
fprintf(stderr, "\nError: Out of memory. "
"Could not exchange to flashback event.\n");
exit(1);
error= true;
goto end;
}

if (length2 != 0) // It has before and after image
Expand Down Expand Up @@ -1237,7 +1247,9 @@ void Rows_log_event::change_to_flashback_event(PRINT_EVENT_INFO *print_event_inf
{
fprintf(stderr, "\nError: Out of memory. "
"Could not push flashback event into array.\n");
exit(1);
my_free(one_row.str);
error= true;
goto end;
}
}

Expand All @@ -1250,15 +1262,24 @@ void Rows_log_event::change_to_flashback_event(PRINT_EVENT_INFO *print_event_inf
rows_pos+= one_row->length;
my_free(one_row->str);
}
delete_dynamic(&rows_arr);

end:
if (bi_fields)
if (error)
{
for (size_t i= 0; i < rows_arr.elements; ++i)
{
LEX_STRING *one_row= dynamic_element(&rows_arr, i, LEX_STRING*);
my_free(one_row->str);
}
}
delete_dynamic(&rows_arr);
err:
if (ai_fields || bi_fields)
{
my_free(bi_fields);
my_free(ai_fields);
}
delete td;
return error;
}

/**
Expand Down Expand Up @@ -1389,11 +1410,10 @@ static size_t calc_field_event_length(const uchar *ptr, uint type, uint meta)

@return length of the parsed row image if succeeds, otherwise 0 is returned.
*/
size_t
Rows_log_event::calc_row_event_length(table_def *td,
MY_BITMAP *cols_bitmap,
const uchar *value,
Field_info *fields)
size_t Rows_log_event::calc_row_event_length(table_def *td,
MY_BITMAP *cols_bitmap,
const uchar *value,
Field_info *fields)
{
const uchar *value0= value;
const uchar *null_bits= value;
Expand All @@ -1417,15 +1437,31 @@ Rows_log_event::calc_row_event_length(table_def *td,
if (!is_null)
{
size_t size;
size_t fsize= td->calc_field_size((uint)i, (uchar*) value);
if (value + fsize > m_rows_end)
const char *event_name= get_type_str();
const bool IsUpdate= get_general_type_code() == UPDATE_ROWS_EVENT ||
get_general_type_code() == UPDATE_ROWS_EVENT_V1;
const char *image_suffix= "";
if (IsUpdate)
image_suffix=
(cols_bitmap == &m_cols_ai) ? " (after image)" : " (before image)";
if (!(size= calc_field_event_length(value, td->type(i),
td->field_metadata(i))))
{
/* Corrupted replication event was detected, skipping entry */
fprintf(stderr, "\nError decoding row image "
"(could not determine field length): "
"event=%s%s, column=%u, column_type=%u, metadata=%u\n",
event_name, image_suffix,
i, (uint) td->type(i), (uint) td->field_metadata(i));
return 0;
}
if (!(size= calc_field_event_length(value, td->type(i),
td->field_metadata(i))))
if (size > (size_t) (m_rows_end - value))
{
/* corrupted replication event was detected, skipping entry */
fprintf(stderr, "\nError decoding row image "
"(field extends past row buffer): "
"event=%s%s, column=%u\n", event_name, image_suffix, i);
return 0;
}

if (fields)
{
Expand Down Expand Up @@ -1693,6 +1729,7 @@ bool Log_event::print_base64(IO_CACHE* file,
{
uint tmp_size= size;
Rows_log_event *ev= NULL;
bool error= false;
Log_event_type ev_type = (enum Log_event_type) ptr[EVENT_TYPE_OFFSET];
if (read_checksum_alg != BINLOG_CHECKSUM_ALG_UNDEF &&
read_checksum_alg != BINLOG_CHECKSUM_ALG_OFF)
Expand All @@ -1702,36 +1739,35 @@ bool Log_event::print_base64(IO_CACHE* file,
ptr[EVENT_TYPE_OFFSET]= DELETE_ROWS_EVENT;
ev= new Delete_rows_log_event(ptr, tmp_size,
glob_description_event);
ev->change_to_flashback_event(print_event_info, ptr, ev_type);
break;
case WRITE_ROWS_EVENT_V1:
ptr[EVENT_TYPE_OFFSET]= DELETE_ROWS_EVENT_V1;
ev= new Delete_rows_log_event(ptr, tmp_size,
glob_description_event);
ev->change_to_flashback_event(print_event_info, ptr, ev_type);
break;
case DELETE_ROWS_EVENT:
ptr[EVENT_TYPE_OFFSET]= WRITE_ROWS_EVENT;
ev= new Write_rows_log_event(ptr, tmp_size,
glob_description_event);
ev->change_to_flashback_event(print_event_info, ptr, ev_type);
break;
case DELETE_ROWS_EVENT_V1:
ptr[EVENT_TYPE_OFFSET]= WRITE_ROWS_EVENT_V1;
ev= new Write_rows_log_event(ptr, tmp_size,
glob_description_event);
ev->change_to_flashback_event(print_event_info, ptr, ev_type);
break;
case UPDATE_ROWS_EVENT:
case UPDATE_ROWS_EVENT_V1:
ev= new Update_rows_log_event(ptr, tmp_size,
glob_description_event);
ev->change_to_flashback_event(print_event_info, ptr, ev_type);
break;
default:
break;
}
if (ev)
error= ev->change_to_flashback_event(print_event_info, ptr, ev_type);
delete ev;
if (unlikely(error))
goto err;
}

if (do_print_encoded)
Expand Down
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