Assertion `partial_join_cost >= -2.2204460492503131e-16' failed in recompute_join_cost_with_limit on SELECT

--source include/have_innodb.inc

CREATE TABLE t (c INT NOT NULL UNIQUE) ENGINE=InnoDB;

INSERT INTO t VALUES (0),(1),(2),(3),(4),(5);

SET optimizer_scan_setup_cost=100000000;

SET optimizer_join_limit_pref_ratio=1;

EXPLAIN SELECT c FROM t ORDER BY c LIMIT 1;

SET optimizer_join_limit_pref_ratio= DEFAULT;

SET optimizer_scan_setup_cost= DEFAULT;

DROP TABLE t;

mariadbd: sql/sql_select.cc:11916: double recompute_join_cost_with_limit(const JOIN *, bool, double *, double): Assertion `partial_join_cost >= -2.2204460492503131e-16' failed.

#0  __pthread_kill_implementation (no_tid=0, signo=6, threadid=<optimized out>)at ./nptl/pthread_kill.c:44

#1  __pthread_kill_internal (signo=6, threadid=<optimized out>)at ./nptl/pthread_kill.c:78

#2  __GI___pthread_kill (threadid=<optimized out>, signo=6)at ./nptl/pthread_kill.c:89

#3  0x000061039347dbe6 in handle_fatal_signal (sig=<optimized out>)at sql/signal_handler.cc:298

#4  <signal handler called>

#5  __pthread_kill_implementation (no_tid=0, signo=6, threadid=<optimized out>)at ./nptl/pthread_kill.c:44

#6  __pthread_kill_internal (signo=6, threadid=<optimized out>)at ./nptl/pthread_kill.c:78

#7  __GI___pthread_kill (threadid=<optimized out>, signo=signo@entry=6)at ./nptl/pthread_kill.c:89

#8  0x00007a769984527e in __GI_raise (sig=sig@entry=6)at ../sysdeps/posix/raise.c:26

#9  0x00007a76998288ff in __GI_abort () at ./stdlib/abort.c:79

#10 0x00007a769982881b in __assert_fail_base (fmt=0x7a76999d1208 "%s%s%s:%u: %s%sAssertion `%s' failed.\n%n", assertion=assertion@entry=0x610392054620 <str> "partial_join_cost >= -2.2204460492503131e-16", file=file@entry=0x61039204aa74 "sql/sql_select.cc", line=line@entry=11916, function=function@entry=0x610392054680 <__PRETTY_FUNCTION__._Z30recompute_join_cost_with_limitPK4JOINbPdd> "double recompute_join_cost_with_limit(const JOIN *, bool, double *, double)") at ./assert/assert.c:96

#11 0x00007a769983b517 in __assert_fail (assertion=0x610392054620 <str> "partial_join_cost >= -2.2204460492503131e-16", file=0x61039204aa74 "sql/sql_select.cc", line=11916, function=0x610392054680 <__PRETTY_FUNCTION__._Z30recompute_join_cost_with_limitPK4JOINbPdd> "double recompute_join_cost_with_limit(const JOIN *, bool, double *, double)") at ./assert/assert.c:105

#12 0x0000610393fb5b6f in recompute_join_cost_with_limit (join=join@entry=0x794698b5e828, skip_sorting=<optimized out>, first_table_cost=first_table_cost@entry=0x6e7599d016b0, fraction=<optimized out>)at sql/sql_select.cc:11916

#13 0x0000610393fabbb7 in join_limit_shortcut_finalize_plan (join=0x794698b5e828, cost=<optimized out>)at sql/sql_select.cc:11988

#14 0x0000610393fa7f62 in choose_plan (join=0x794698b5e828, join_tables=<optimized out>, emb_sjm_nest=<optimized out>)at sql/sql_select.cc:10391

#15 0x0000610393f1bb03 in make_join_statistics (join=0x794698b5e828, tables_list=<optimized out>, keyuse_array=<optimized out>)at sql/sql_select.cc:6382

#16 0x0000610393ef38a9 in JOIN::optimize_inner (this=0x794698b5e828)at sql/sql_select.cc:2764

#17 0x0000610393eecfd7 in JOIN::optimize (this=<optimized out>)at sql/sql_select.cc:2017

#18 0x0000610393ecbf9b in mysql_select (thd=0x793698b90220, tables=<optimized out>, fields=<optimized out>, conds=<optimized out>, og_num=<optimized out>, order=<optimized out>, group=0x0, having=0x0, proc_param=0x0, select_options=<optimized out>, result=0x794698b5df80, unit=0x793698b947b8, select_lex=0x794698b5c518)at sql/sql_select.cc:5426

#19 0x0000610394049310 in mysql_explain_union (thd=<optimized out>, unit=0x793698b947b8, result=<optimized out>)at sql/sql_select.cc:31992

#20 0x0000610393d61ef8 in execute_sqlcom_select (thd=0x793698b90220, all_tables=<optimized out>)at sql/sql_parse.cc:6168

#21 0x0000610393d4cffd in mysql_execute_command (thd=0x793698b90220, is_called_from_prepared_stmt=<optimized out>)at sql/sql_parse.cc:3997

#22 0x0000610393d26c5b in mysql_parse (thd=thd@entry=0x793698b90220, rawbuf=<optimized out>, length=<optimized out>, parser_state=<optimized out>)at sql/sql_parse.cc:7968

#23 0x0000610393d1ec3f in dispatch_command (command=<optimized out>, thd=0x793698b90220, packet=<optimized out>, packet_length=<optimized out>, blocking=<optimized out>)at sql/sql_parse.cc:1903

#24 0x0000610393d29047 in do_command (thd=thd@entry=0x793698b90220, blocking=<optimized out>)at sql/sql_parse.cc:1437

#25 0x000061039456906d in do_handle_one_connection (connect=<optimized out>, connect@entry=0x7726989e3d90, put_in_cache=<optimized out>)at sql/sql_connect.cc:1514

#26 0x0000610394568b96 in handle_one_connection (arg=0x7726989e3d90)at sql/sql_connect.cc:1426

#27 0x00007a769a148e17 in asan_thread_start ()

#28 0x00007a769989cb84 in start_thread (arg=<optimized out>)at ./nptl/pthread_create.c:447

--source include/have_innodb.inc

--source include/have_sequence.inc

CREATE TABLE t (c INT NOT NULL UNIQUE) ENGINE=InnoDB;

INSERT INTO t SELECT seq FROM seq_1_to_100000;

SET optimizer_join_limit_pref_ratio=1;

--disable_result_log

EXPLAIN SELECT c FROM t ORDER BY c LIMIT 28000;

--enable_result_log

SET optimizer_join_limit_pref_ratio= DEFAULT;

DROP TABLE t;

Compiled with Clang (22.1.8 here) with:

    -DWITH_ASAN=ON -DWITH_ASAN_SCOPE=ON -DWITH_UBSAN=ON -DWSREP_LIB_WITH_ASAN=ON

    -DCMAKE_C{,XX}_FLAGS='-O1 -march=native'

The -march=native matters. It gives Clang an FMA instruction, and the fused

multiply-add is what leaves the negative value behind. A build of the same

source without it does not abort.