The assert was observed on the trees

-    10.2 commit 27664ef29d97be2973982aedcc0c8c90d18b20a4 2019-10-08

    and

-     bb-10.2-merge commit d9f224233497ce5e3706fe6539a2b711b491af1d 2019-10-08

Hitting that assert is very rare (one per ~ 700 RQG test runs).

The snippets of logs belong to the test run on bb-10.2-merge which contains

- a fix for https://jira.mariadb.org/browse/MDEV-19335 (fix is currently in review)

- some merge from 10.1

10.2.28-MariaDB-debug-log

2019-10-08 13:29:21 0x7f3bbc51b700  InnoDB: Assertion failure in file storage/innobase/btr/btr0cur.cc line 1434

InnoDB: Failing assertion: !page_zip || page_zip_validate(page_zip, page, index)

...

Query (0x7f3b140104e0): UPDATE `t7` SET `pad` = 'o' WHERE `id` = 2942 /* E_R Thread2 QNO 1599 CON_ID 20 */

Connection ID (thread ID): 20

Status: NOT_KILLED

#3  <signal handler called>

#4  __GI_raise (sig=sig@entry=6) at ../sysdeps/unix/sysv/linux/raise.c:58

#5  0x00007f3bc40ad37a in __GI_abort () at abort.c:89

#6  0x000055c433c9e014 in ut_dbg_assertion_failed (expr=0x55c4342cfe10 "!page_zip || page_zip_validate(page_zip, page, index)", file=0x55c4342cf0a0 "storage/innobase/btr/btr0cur.cc", line=1434) at storage/innobase/ut/ut0dbg.cc:60

#7  0x000055c433cc8e39 in btr_cur_search_to_nth_level (index=0x7f3b0c042d18, level=0, tuple=0x7f3b14060058, mode=PAGE_CUR_GE, latch_mode=1, cursor=0x7f3b1405fe68, has_search_latch=0, file=0x55c434282818 "storage/innobase/row/row0sel.cc", line=4724, mtr=0x7f3bbc5188d0, autoinc=0) at storage/innobase/btr/btr0cur.cc:1434

#8  0x000055c433bfb479 in btr_pcur_open_with_no_init_func (index=0x7f3b0c042d18, tuple=0x7f3b14060058, mode=PAGE_CUR_GE, latch_mode=1, cursor=0x7f3b1405fe68, has_search_latch=0, file=0x55c434282818 "storage/innobase/row/row0sel.cc", line=4724, mtr=0x7f3bbc5188d0) at storage/innobase/include/btr0pcur.ic:527

#9  0x000055c433c05f52 in row_search_mvcc (buf=0x7f3b14022fe8 "\377", mode=PAGE_CUR_GE, prebuilt=0x7f3b1405fc98, match_mode=1, direction=0) at storage/innobase/row/row0sel.cc:4722

#10 0x000055c433a9488f in ha_innobase::index_read (this=0x7f3b14029130, buf=0x7f3b14022fe8 "\377", key_ptr=0x7f3b140556d0 "~\v", key_len=4, find_flag=HA_READ_KEY_EXACT) at storage/innobase/handler/ha_innodb.cc:9471

#11 0x000055c433890b4c in handler::index_read_map (this=0x7f3b14029130, buf=0x7f3b14022fe8 "\377", key=0x7f3b140556d0 "~\v", keypart_map=1, find_flag=HA_READ_KEY_EXACT) at sql/handler.h:3136

#12 0x000055c433886d8a in handler::ha_index_read_map (this=0x7f3b14029130, buf=0x7f3b14022fe8 "\377", key=0x7f3b140556d0 "~\v", keypart_map=1, find_flag=HA_READ_KEY_EXACT) at sql/handler.cc:2711

#13 0x000055c43388d962 in handler::read_range_first (this=0x7f3b14029130, start_key=0x7f3b14029218, end_key=0x7f3b14029238, eq_range_arg=true, sorted=true) at sql/handler.cc:5458

#14 0x000055c43379cbc6 in handler::multi_range_read_next (this=0x7f3b14029130, range_info=0x7f3bbc519110) at sql/multi_range_read.cc:298

#15 0x000055c43379ccff in Mrr_simple_index_reader::get_next (this=0x7f3b140296a0, range_info=0x7f3bbc519110) at sql/multi_range_read.cc:335

#16 0x000055c43379f840 in DsMrr_impl::dsmrr_next (this=0x7f3b14029560, range_info=0x7f3bbc519110) at sql/multi_range_read.cc:1411

#17 0x000055c433aa984e in ha_innobase::multi_range_read_next (this=0x7f3b14029130, range_info=0x7f3bbc519110) at storage/innobase/handler/ha_innodb.cc:21332

#18 0x000055c4339df8d2 in QUICK_RANGE_SELECT::get_next (this=0x7f3b1401ada0) at sql/opt_range.cc:11473

#19 0x000055c4339f0882 in rr_quick (info=0x7f3bbc519350) at sql/records.cc:365

#20 0x000055c4336f219b in mysql_update (thd=0x7f3b14000a98, table_list=0x7f3b14010640, fields=..., values=..., conds=0x7f3b14010fe8, order_num=0, order=0x0, limit=18446744073709551615, handle_duplicates=DUP_ERROR, ignore=false, found_return=0x7f3bbc5198c0, updated_return=0x7f3bbc519970) at sql/sql_update.cc:749

#21 0x000055c433602a1f in mysql_execute_command (thd=0x7f3b14000a98) at sql/sql_parse.cc:4014

#22 0x000055c43360e8a0 in mysql_parse (thd=0x7f3b14000a98, rawbuf=0x7f3b140104e0 "UPDATE `t7` SET `pad` = 'o' WHERE `id` = 2942 /* E_R Thread2 QNO 1599 CON_ID 20 */", length=82, parser_state=0x7f3bbc51a250, is_com_multi=false, is_next_command=false) at sql/sql_parse.cc:7759

#23 0x000055c4335fcba9 in dispatch_command (command=COM_QUERY, thd=0x7f3b14000a98, packet=0x7f3b140081a9 "UPDATE `t7` SET `pad` = 'o' WHERE `id` = 2942 /* E_R Thread2 QNO 1599 CON_ID 20 */ ", packet_length=83, is_com_multi=false, is_next_command=false) at sql/sql_parse.cc:1831

#24 0x000055c4335fb4fd in do_command (thd=0x7f3b14000a98) at sql/sql_parse.cc:1384

#25 0x000055c433750957 in do_handle_one_connection (connect=0x55c4372aed98) at sql/sql_connect.cc:1336

#26 0x000055c4337506c2 in handle_one_connection (arg=0x55c4372aed98) at sql/sql_connect.cc:1241

#27 0x00007f3bc4cec6da in start_thread (arg=0x7f3bbc51b700) at pthread_create.c:456