100% CPU usage with ST_UNION in maria-5.3-gis

[Philip Stoev]

maria-5.3-gis can not calculate the following expression:

SELECT ST_UNION(GEOMETRYFROMTEXT(' POINT( 8 1 ) ') ,MULTILINESTRINGFROMTEXT(' MULTILINESTRING( (3 5, 2 5, 2 4, 3 4, 3 5) ) '));

the server enters into an endless, unkillable loop:

(gdb) next
1167 while (next)
(gdb)
1169 cur= next;
(gdb)
1170 next= move_upward ? next->up : next->down;
(gdb)
1171 if (!next)
(gdb)
1167 while (next)

bzr version-info
revision-id: <email address hidden>
date: 2011-09-01 11:44:56 +0500
build-date: 2011-09-02 10:30:29 +0300
revno: 2993
branch-nick: maria-5.3-gis

backtrace:

#0 0x08368bbe in Gcalc_operation_reducer::get_line_result (this=0xac7e424, cur=0xac8c7a0, storage=0xac7e3c8) at gcalc_tools.cc:1171
#1 0x08368e83 in Gcalc_operation_reducer::get_result (this=0xac7e424, storage=0xac7e3c8) at gcalc_tools.cc:1234
#2 0x0825c2b6 in Item_func_spatial_operation::val_str (this=0xac7e248, str_value=0xa4772060) at item_geofunc.cc:1039
#3 0x081dbb51 in Item::send (this=0xac7e248, protocol=0xabcca84, buffer=0xa4772060) at item.cc:5905
#4 0x082894bc in select_send::send_data (this=0xac7e608, items=...) at sql_class.cc:1919
#5 0x0832630c in JOIN::exec (this=0xac83468) at sql_select.cc:2069
#6 0x08328d28 in mysql_select (thd=0xabcc758, rref_pointer_array=0xabce270, tables=0x0, wild_num=0, fields=..., conds=0x0, og_num=0, order=0x0, group=0x0,
    having=0x0, proc_param=0x0, select_options=2147764736, result=0xac7e608, unit=0xabcde74, select_lex=0xabce150) at sql_select.cc:2885
#7 0x08320bf3 in handle_select (thd=0xabcc758, lex=0xabcde18, result=0xac7e608, setup_tables_done_option=0) at sql_select.cc:283
#8 0x082bc323 in execute_sqlcom_select (thd=0xabcc758, all_tables=0x0) at sql_parse.cc:5082
#9 0x082b3127 in mysql_execute_command (thd=0xabcc758) at sql_parse.cc:2227
#10 0x082be95f in mysql_parse (thd=0xabcc758,
    rawbuf=0xac7db78 "SELECT ST_UNION(GEOMETRYFROMTEXT(' POINT( 8 1 ) ') ,MULTILINESTRINGFROMTEXT(' MULTILINESTRING( (3 5, 2 5, 2 4, 3 4, 3 5) ) '))",
    length=128, found_semicolon=0xa4773228) at sql_parse.cc:6083
#11 0x082b0dc3 in dispatch_command (command=COM_QUERY, thd=0xabcc758, packet=0xac670d1 "", packet_length=128) at sql_parse.cc:1206
#12 0x082b0249 in do_command (thd=0xabcc758) at sql_parse.cc:904
#13 0x082ad2c4 in handle_one_connection (arg=0xabcc758) at sql_connect.cc:1177
#14 0x00821919 in start_thread () from /lib/libpthread.so.0
#15 0x00453cce in clone () from /lib/libc.so.6