CREATE TABLE IF NOT EXISTS t4 (

col1 INT,

col2 INT,

col_int INTEGER,

col_string VARCHAR(19),

col_varchar VARCHAR(500),

col_text TEXT,

col_int_g INTEGER GENERATED ALWAYS AS (col_int) PERSISTENT,

col_string_g VARCHAR(13) GENERATED ALWAYS AS (SUBSTR(col_string,4,13)) PERSISTENT,

col_text_g TEXT GENERATED ALWAYS AS (SUBSTR(col_text,1,499)) PERSISTENT)

ENGINE = InnoDB ROW_FORMAT = Redundant;

# The assert disappears if using "ENGINE = InnoDB" and not "ROW_FORMAT = Redundant".

ALTER TABLE t4 ADD PRIMARY KEY (col_text(9));

ALTER TABLE t4 DROP PRIMARY KEY;

ALTER TABLE t4 CHANGE COLUMN col_text col_text TEXT;

INSERT INTO t4 (col1) VALUES (NULL);

ALTER TABLE t4 MODIFY COLUMN col1 INT AFTER col_int;

ALTER TABLE t4 ADD COLUMN col_text_g_copy TEXT

GENERATED ALWAYS AS (SUBSTR(col_text,1,499)) VIRTUAL AFTER col1;

ALTER TABLE t4 DROP COLUMN col_text_g;

ERROR HY000: Lost connection to MySQL server during query

DROP TABLE t4;

...

Version: '10.4.3-MariaDB-debug-log'  ...

mysqld: storage/innobase/btr/btr0btr.cc:1936: void btr_set_instant(buf_block_t*, const dict_index_t&, mtr_t*): Assertion `supremum[7] == index.n_core_null_bytes' failed.

190219 16:49:46 [ERROR] mysqld got signal 6 ;

...

Query (0x7f9b080145a0): ALTER TABLE t4 DROP COLUMN col_text_g

Connection ID (thread ID): 9

Status: NOT_KILLED

...

#3  <signal handler called>

#4  __GI_raise (sig=sig@entry=6) at ../sysdeps/unix/sysv/linux/raise.c:51

#5  0x00007f9b649fff5d in __GI_abort () at abort.c:90

#6  0x00007f9b649f5f17 in __assert_fail_base (fmt=<optimized out>, assertion=assertion@entry=0x558ed002f598 "supremum[7] == index.n_core_null_bytes", file=file@entry=0x558ed002e660 "storage/innobase/btr/btr0btr.cc", line=line@entry=1936, function=function@entry=0x558ed0033060 <btr_set_instant(buf_block_t*, dict_index_t const&, mtr_t*)::__PRETTY_FUNCTION__> "void btr_set_instant(buf_block_t*, const dict_index_t&, mtr_t*)") at assert.c:92

#7  0x00007f9b649f5fc2 in __GI___assert_fail (assertion=0x558ed002f598 "supremum[7] == index.n_core_null_bytes", file=0x558ed002e660 "storage/innobase/btr/btr0btr.cc", line=1936, function=0x558ed0033060 <btr_set_instant(buf_block_t*, dict_index_t const&, mtr_t*)::__PRETTY_FUNCTION__> "void btr_set_instant(buf_block_t*, const dict_index_t&, mtr_t*)") at assert.c:101

#8  0x0000558ecf8fcab8 in btr_set_instant (root=0x7f9b5dfe1e70, index=..., mtr=0x7f9b5dd17090) at storage/innobase/btr/btr0btr.cc:1936

#9  0x0000558ecf700013 in innobase_instant_try (ha_alter_info=0x7f9b5dd18a90, ctx=0x7f9b08016928, altered_table=0x7f9b08071b58, table=0x7f9b08043f68, trx=0x7f9b5e803268) at storage/innobase/handler/handler0alter.cc:5699

#10 0x0000558ecf71c2de in commit_try_norebuild (ha_alter_info=0x7f9b5dd18a90, ctx=0x7f9b08016928, altered_table=0x7f9b08071b58, old_table=0x7f9b08043f68, trx=0x7f9b5e803268, table_name=0x7f9b08071945 "t4") at storage/innobase/handler/handler0alter.cc:10129

#11 0x0000558ecf70e395 in ha_innobase::commit_inplace_alter_table (this=0x7f9b080e5e40, altered_table=0x7f9b08071b58, ha_alter_info=0x7f9b5dd18a90, commit=true) at storage/innobase/handler/handler0alter.cc:10794

#12 0x0000558ecf4a0c23 in handler::ha_commit_inplace_alter_table (this=0x7f9b080e5e40, altered_table=0x7f9b08071b58, ha_alter_info=0x7f9b5dd18a90, commit=true) at sql/handler.cc:4673

#13 0x0000558ecf23b8be in mysql_inplace_alter_table (thd=0x7f9b08000ce8, table_list=0x7f9b08014698, table=0x7f9b08043f68, altered_table=0x7f9b08071b58, ha_alter_info=0x7f9b5dd18a90, inplace_supported=HA_ALTER_INPLACE_INSTANT, target_mdl_request=0x7f9b5dd18cc0, alter_ctx=0x7f9b5dd19270) at sql/sql_table.cc:7602

#14 0x0000558ecf2416f1 in mysql_alter_table (thd=0x7f9b08000ce8, new_db=0x7f9b080053f8, new_name=0x7f9b080057f8, create_info=0x7f9b5dd19e60, table_list=0x7f9b08014698, alter_info=0x7f9b5dd19da0, order_num=0, order=0x0, ignore=false) at sql/sql_table.cc:9700

#15 0x0000558ecf2ccb9f in Sql_cmd_alter_table::execute (this=0x7f9b08014d00, thd=0x7f9b08000ce8) at sql/sql_alter.cc:493

#16 0x0000558ecf16329f in mysql_execute_command (thd=0x7f9b08000ce8) at sql/sql_parse.cc:6330

#17 0x0000558ecf1686f2 in mysql_parse (thd=0x7f9b08000ce8, rawbuf=0x7f9b080145a0 "ALTER TABLE t4 DROP COLUMN col_text_g", length=37, parser_state=0x7f9b5dd1b1e0, is_com_multi=false, is_next_command=false) at sql/sql_parse.cc:8141

#18 0x0000558ecf153b02 in dispatch_command (command=COM_QUERY, thd=0x7f9b08000ce8, packet=0x7f9b0800a009 "ALTER TABLE t4 DROP COLUMN col_text_g", packet_length=37, is_com_multi=false, is_next_command=false) at sql/sql_parse.cc:1819

#19 0x0000558ecf15234a in do_command (thd=0x7f9b08000ce8) at sql/sql_parse.cc:1357

#20 0x0000558ecf2c6add in do_handle_one_connection (connect=0x558ed1a73be8) at sql/sql_connect.cc:1399

#21 0x0000558ecf2c6841 in handle_one_connection (arg=0x558ed1a73be8) at sql/sql_connect.cc:1302

#22 0x0000558ecfbf8c54 in pfs_spawn_thread (arg=0x558ed1aba1d8) at storage/perfschema/pfs.cc:1862

#23 0x00007f9b658a57fc in start_thread (arg=0x7f9b5dd1c700) at pthread_create.c:465

#24 0x00007f9b64adbb5f in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

10.4 commit abd3c202f6227a46f50c0d93cb621c9ed1e499c0 2019-02-19

The problem was not repeatable on

- 10.3 commit e8b6c15010e6fffe17e27c165b8c60b51a8f66a7 2019-02-13

- 10.2 commit af6fdc13072cc310cf17fd3b28c749515d9c563c 2019-02-19