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use_stat_tables='preferably' optimizer_use_condition_selectivity=4 histogram_size=255
Thread pointer: 0x0x7f187cf92008 Attempting backtrace. You can use the following information to find out where mysqld died. If you see no messages after this, something went terribly wrong... stack_bottom = 0x7f1cb5654d10 thread_stack 0x48000 /usr/sbin/mysqld(my_print_stacktrace+0x2b)[0xb7054b] /usr/sbin/mysqld(handle_fatal_signal+0x398)[0x727588] /lib64/libpthread.so.0(+0xf710)[0x7f1cb531a710] /usr/sbin/mysqld(_ZN9Field_bit5storeEPKcjPK15charset_info_st+0x10f)[0x713caf] /usr/sbin/mysqld(_Z28get_column_range_cardinalityP5FieldP12st_key_rangeS2_j+0x135)[0x63f605] /usr/sbin/mysqld(_Z36calculate_cond_selectivity_for_tableP3THDP5TABLEP4Item+0x836)[0x80bd76] /usr/sbin/mysqld[0x528cce] /usr/sbin/mysqld(_ZN4JOIN14optimize_innerEv+0x6de)[0x61c8de] /usr/sbin/mysqld(_Z12mysql_selectP3THDPPP4ItemP10TABLE_LISTjR4ListIS1_ES2_jP8st_orderSB_S2_SB_yP13select_resultP18st_select_lex_unitP13st_select_lex+0xd8)[0x61efb8] /usr/sbin/mysqld(_Z13handle_selectP3THDP3LEXP13select_resultm+0x28d)[0x62284d] /usr/sbin/mysqld[0x5ca456] /usr/sbin/mysqld(_Z21mysql_execute_commandP3THD+0x4c4f)[0x5d51af] /usr/sbin/mysqld[0x5d6cc2] /usr/sbin/mysqld(_Z16dispatch_command19enum_server_commandP3THDPcj+0x1b20)[0x5d8e80] /usr/sbin/mysqld(_Z24do_handle_one_connectionP3THD+0x453)[0x696993] /usr/sbin/mysqld(handle_one_connection+0x42)[0x696a62] /lib64/libpthread.so.0(+0x79d1)[0x7f1cb53129d1] /lib64/libc.so.6(clone+0x6d)[0x7f1cb3a2fb5d]
Trying to get some variables. Some pointers may be invalid and cause the dump to abort. Query (0x7f1859c20020): SELECT id, reportName, scheduleName, reportId, reportScheduleId, reportType, status, reportFormat, generationStartTime, executionTime, fileUrl, fileSize, retainUntil, users, userGroups, recurrenceType, recurrenceIntervalType, recurrenceIntervalValue, recurrenceParam1, recurrenceParam2, recurrenceParam3, reportSource, userId, isGloballyViewable, retainLast FROM report_schedule_logs WHERE ((`retainUntil` < 20140912114319) AND (`retainLast` != true)) Connection ID (thread ID): 4 Status: NOT_KILLED
CREATE TABLE `report_schedule_logs` (
`id` int(10) unsigned NOT NULL AUTO_INCREMENT,
`reportName` varchar(128) DEFAULT NULL,
`scheduleName` varchar(128) DEFAULT NULL,
`reportId` varchar(255) DEFAULT NULL,
`reportScheduleId` varchar(255) DEFAULT NULL,
`reportType` int(10) unsigned DEFAULT NULL,
`reportFormat` tinyint(3) unsigned DEFAULT NULL,
`generationStartTime` timestamp NOT NULL DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP,
`executionTime` varchar(128) DEFAULT NULL,
`reportSource` tinyint(3) unsigned DEFAULT NULL,
`status` tinyint(3) unsigned DEFAULT NULL,
`fileUrl` varchar(1024) DEFAULT NULL,
`fileSize` bigint(20) DEFAULT NULL,
`retainUntil` timestamp NOT NULL DEFAULT '0000-00-00 00:00:00',
`retainLast` bit(1) DEFAULT b'0',
`users` longblob,
`userGroups` longblob,
`recurrenceType` tinyint(3) unsigned DEFAULT NULL,
`recurrenceIntervalType` tinyint(3) unsigned DEFAULT NULL,
`recurrenceIntervalValue` int(11) DEFAULT NULL,
`recurrenceParam1` varchar(128) DEFAULT NULL,
`recurrenceParam2` varchar(128) DEFAULT NULL,
`recurrenceParam3` varchar(128) DEFAULT NULL,
`userId` varchar(128) DEFAULT NULL,
`isGloballyViewable` bit(1) DEFAULT NULL,
PRIMARY KEY (`id`),
KEY `report_schedule_logs_idx1` (`status`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8
explain SELECT id, reportName, scheduleName, reportId, reportScheduleId, reportType, status, reportFormat, generationStartTime, executionTime, fileUrl, fileSize, retainUntil, users, userGroups, recurrenceType, recurrenceIntervalType, recurrenceIntervalValue, recurrenceParam1, recurrenceParam2, recurrenceParam3, reportSource, userId, isGloballyViewable, retainLast FROM report_schedule_logs WHERE ((`retainUntil` < 20140912114319) AND (`retainLast` != true));
changing the configuration to default instanlty solve the issue .
show variables like 'optimizer_use_condition_selectivity'; +-------------------------------------+-------+ | Variable_name | Value | +-------------------------------------+-------+ | optimizer_use_condition_selectivity | 4 | +-------------------------------------+-------+ 1 row in set (0.00 sec) MariaDB [sa]> explain SELECT id, reportName, scheduleName, reportId, reportScheduleId, reportType, status, reportFormat, generationStartTime, executionTime, fileUrl, fileSize, retainUntil, users, userGroups, recurrenceType, recurrenceIntervalType, recurrenceIntervalValue, recurrenceParam1, recurrenceParam2, recurrenceParam3, reportSource, userId, isGloballyViewable, retainLast FROM report_schedule_logs WHERE ((`retainUntil` < 20140912114319) AND (`retainLast` != true)); ERROR 2013 (HY000): Lost connection to MySQL server during query
MariaDB [sa]> show variables like 'optimizer_use_condition_selectivity';ERROR 2006 (HY000): MySQL server has gone awayNo connection. Trying to reconnect... Connection id: 6 Current database: sa +-------------------------------------+-------+ | Variable_name | Value | +-------------------------------------+-------+ | optimizer_use_condition_selectivity | 1 | +-------------------------------------+-------+ 1 row in set (0.46 sec) MariaDB [sa]> explain SELECT id, reportName, scheduleName, reportId, reportScheduleId, reportType, status, reportFormat, generationStartTime, executionTime, fileUrl, fileSize, retainUntil, users, userGroups, recurrenceType, recurrenceIntervalType, recurrenceIntervalValue, recurrenceParam1, recurrenceParam2, recurrenceParam3, reportSource, userId, isGloballyViewable, retainLast FROM report_schedule_logs WHERE ((`retainUntil` < 20140912114319) AND (`retainLast` != true)); +------+-------------+----------------------+------+---------------+------+---------+------+------+-------------+ | id | select_type | table | type | possible_keys | key | key_len | ref | rows | Extra | +------+-------------+----------------------+------+---------------+------+---------+------+------+-------------+ | 1 | SIMPLE | report_schedule_logs | ALL | NULL | NULL | NULL | NULL | 1 | Using where | +------+-------------+----------------------+------+---------------+------+---------+------+------+-------------+
The context is that our client under support benefit from histograms on some query plan. We activated it but after a process of reseting the data . it started to crash on this query run every 5 minutes. not that after the reset we did no run analyze table but the table was readable and and was empty.
the content of the stats tables because are empty ! due to restart
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MDEV-6519 Assertion `join->best_read < double(...)' failed after adding a key to a TokuDB table, use_stat_tables, optimizer_use_condition_selectivity>1
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Still repeatable after fix for MDEV-6442.
We crash in Field_bit::store on this line
set_rec_bits((1 << bit_len) - 1, bit_ptr, bit_ofs, bit_len);
because of this
(gdb) print bit_ptr $34 = (uchar *) 0x36000 <Address 0x36000 out of bounds>
Field_bit refers to the "retainLast" field.
The first guess is that create_min_max_fields_for_table[share] create invalid field objects is incorrect.
Running
select retainLast FROM report_schedule_logs
shows that "regular" field objects also have bit_ptr pointing to nowhere:
Breakpoint 7, sub_select (join=0x7fffcac20978, join_tab=0x7fffcac218b0, end_of_records=false) at /home/psergey/dev2/10.0/sql/sql_select.cc:17587 (gdb) p join_tab->table->field[14] $125 = (Field_bit_as_char *) 0x7fffcac3e8e8 (gdb) p join_tab->table->field[14]->bit_ptr $126 = (uchar *) 0x36000 <Address 0x36000 out of bounds>
A smaller testcase:
set use_stat_tables='preferably'; set optimizer_use_condition_selectivity=4; set histogram_size=255; create table t1(col1 int, col2 bit(1) DEFAULT NULL) engine=innodb; select * from t1 where col2 != true;
Program received signal SIGSEGV, Segmentation fault. 0x00000000008473c0 in Field_bit::store (this=0x7ffe9c010130, from=0x7ffff7f80ba7 "\001@\307\301", length=2, cs=0x17d7900) at /home/psergey/dev2/10.0/sql/field.cc:8526 (gdb) wher #0 0x00000000008473c0 in Field_bit::store (this=0x7ffe9c010130, from=0x7ffff7f80ba7 "\001@\307\301", length=2, cs=0x17d7900) at /home/psergey/dev2/10.0/sql/field.cc:8526 #1 0x0000000000851133 in Field_bit::set_key_image (this=0x7ffe9c010130, buff=0x7ffff7f80ba7 "\001@\307\301", length=2) at /home/psergey/dev2/10.0/sql/field.h:2753 #2 0x0000000000973501 in store_key_image_to_rec (field=0x7ffe9c010130, ptr=0x7ffff7f80ba7 "\001@\307\301", len=2) at /home/psergey/dev2/10.0/sql/opt_range.cc:3765 #3 0x00000000006fffee in get_column_range_cardinality (field=0x7ffe9c010130, min_endp=0x7ffff7f7f920, max_endp=0x7ffff7f7f940, range_flag=12) at /home/psergey/dev2/10.0/sql/sql_statistics.cc:3567 #4 0x0000000000972651 in records_in_column_ranges (param=0x7ffff7f7fb50, idx=0, tree=0x7ffe9c065290) at /home/psergey/dev2/10.0/sql/opt_range.cc:3421 #5 0x0000000000972e35 in calculate_cond_selectivity_for_table (thd=0xe6857a0, table=0x7ffe9c00d5d0, cond=0x7ffe9c006f98) at /home/psergey/dev2/10.0/sql/opt_range.cc:3628 #6 0x00000000006a33e4 in make_join_statistics (join=0x7ffe9c0071d8, tables_list=..., conds=0x7ffe9c006f98, keyuse_array=0x7ffe9c0074e0) at /home/psergey/dev2/10.0/sql/sql_select.cc:3949
Field_bit::store() crashes only when the parameter is length=2. If it is
length==1, then there is no crash. I still think there should be no crash
when length==2, either, however when I tried to get other code to call this
function with length=2, I did not succeed.
length=2 because the first byte is NULL-flag, and the next byte holds the bit
value.
store_key_image_to_rec looks like this:
void store_key_image_to_rec(Field *field, uchar *ptr, uint len)
{
/* Do the same as print_key() does */
my_bitmap_map *old_map;
if (field->real_maybe_null())
{
if (*ptr)
{
field->set_null();
return;
}
field->set_notnull();
ptr++;
}
old_map= dbug_tmp_use_all_columns(field->table,
field->table->write_set);
field->set_key_image(ptr, len);
Note: we skip the NULL-byte in the ptr, but we don't decrease 'len'.
Searching for how other code calls store_key_image_to_rec, one can see:
store_key_image_to_rec(sel_arg->field, sel_arg->min_value,
parts[sel_arg->part].length);
store_key_image_to_rec(part->field, arg->min_value, part->length);
and KEY_PART_INFO::length is defined as:
/* Length of key part in bytes, excluding NULL flag and length bytes */ uint16 length;
So, a possible fix is to make EITS code substract HA_KEY_NULL_LENGTH before calling store_key_image_to_rec.
You are missing ANALYZE TABLE after table creation, so the client wouldn't benefit from histograms even without a crash.
If you add ANALYZE TABLE, the crash is gone.
We have a bug report about a failure without statistics in the stat tables (
MDEV-6442), but there we are getting an assertion failure, and here we have a crash, so I'm assigning it to Sergei Petrunia to either make sure it's the same bug, or to fix it separately.