This problem was introduced in
marko.makela@oracle.com-20100514130815-ym7j7cfu88ro6km4
and is probably the reason for the following valgrind warning:

from http://bugs.mysql.com/52691 , http://bugs.mysql.com/file.php?id=16880 :

Version: '5.6.3-m5-valgrind-max-debug'  socket: '/tmp/mysql.sock'  port: 3306  Source distribution
==14947== Thread 18:
==14947== Conditional jump or move depends on uninitialised value(s)
==14947==    at 0x4A06318: __GI_strlen (mc_replace_strmem.c:284)
==14947==    by 0x9F3D7A: fill_innodb_trx_from_cache(trx_i_s_cache_struct*, THD*, TABLE*) (i_s.cc:591)
==14947==    by 0x9F4D7D: trx_i_s_common_fill_table(THD*, TABLE_LIST*, Item*) (i_s.cc:1238)
==14947==    by 0x7689F3: get_schema_tables_result(JOIN*, enum_schema_table_state) (sql_show.cc:6745)
==14947==    by 0x715A75: JOIN::exec() (sql_select.cc:2861)
==14947==    by 0x7185BD: mysql_select(THD*, Item***, TABLE_LIST*, unsigned int, List<Item>&, Item*, unsigned int, st_order*, st_order*, Item*, st_order*, unsigned long long, select_result*, st_select_lex_unit*, st_select_lex*) (sql_select.cc:3609)
==14947==    by 0x70E823: handle_select(THD*, LEX*, select_result*, unsigned long) (sql_select.cc:319)
==14947==    by 0x6F2305: execute_sqlcom_select(THD*, TABLE_LIST*) (sql_parse.cc:4557)
==14947==    by 0x6EAED4: mysql_execute_command(THD*) (sql_parse.cc:2135)
==14947==    by 0x6F44C9: mysql_parse(THD*, char*, unsigned int, Parser_state*) (sql_parse.cc:5597)
==14947==    by 0x6E864B: dispatch_command(enum_server_command, THD*, char*, unsigned int) (sql_parse.cc:1093)
==14947==    by 0x6E785E: do_command(THD*) (sql_parse.cc:815)
==14947==    by 0x6C18DD: do_handle_one_connection(THD*) (sql_connect.cc:771)
==14947==    by 0x6C146E: handle_one_connection (sql_connect.cc:707)
==14947==    by 0x30E1807760: start_thread (pthread_create.c:301)
==14947==    by 0x35EA670F: ???
==14947==  Uninitialised value was created by a heap allocation
==14947==    at 0x4A0515D: malloc (vg_replace_malloc.c:195)
==14947==    by 0xB4B948: mem_area_alloc (mem0pool.c:385)
==14947==    by 0xB4A27C: mem_heap_create_block (mem0mem.c:333)
==14947==    by 0xB4A530: mem_heap_add_block (mem0mem.c:446)
==14947==    by 0xB0D2A4: mem_heap_alloc (mem0mem.ic:186)
==14947==    by 0xB0D9C2: ha_storage_put_memlim (ha0storage.c:118)
==14947==    by 0xA479D8: fill_trx_row (trx0i_s.c:521)
==14947==    by 0xA490E9: fetch_data_into_cache (trx0i_s.c:1319)
==14947==    by 0xA491BA: trx_i_s_possibly_fetch_data_into_cache (trx0i_s.c:1352)
==14947==    by 0x9F4CE7: trx_i_s_common_fill_table(THD*, TABLE_LIST*, Item*) (i_s.cc:1221)
==14947==    by 0x7689F3: get_schema_tables_result(JOIN*, enum_schema_table_state) (sql_show.cc:6745)
==14947==    by 0x715A75: JOIN::exec() (sql_select.cc:2861)
==14947==    by 0x7185BD: mysql_select(THD*, Item***, TABLE_LIST*, unsigned int, List<Item>&, Item*, unsigned int, st_order*, st_order*, Item*, st_order*, unsigned long long, select_result*, st_select_lex_unit*, st_select_lex*) (sql_select.cc:3609)
==14947==    by 0x70E823: handle_select(THD*, LEX*, select_result*, unsigned long) (sql_select.cc:319)
==14947==    by 0x6F2305: execute_sqlcom_select(THD*, TABLE_LIST*) (sql_parse.cc:4557)
==14947==    by 0x6EAED4: mysql_execute_command(THD*) (sql_parse.cc:2135)
==14947==    by 0x6F44C9: mysql_parse(THD*, char*, unsigned int, Parser_state*) (sql_parse.cc:5597)
==14947==    by 0x6E864B: dispatch_command(enum_server_command, THD*, char*, unsigned int) (sql_parse.cc:1093)
==14947==    by 0x6E785E: do_command(THD*) (sql_parse.cc:815)
==14947==    by 0x6C18DD: do_handle_one_connection(THD*) (sql_connect.cc:771)
==14947==    by 0x6C146E: handle_one_connection (sql_connect.cc:707)
==14947==    by 0x30E1807760: start_thread (pthread_create.c:301)
==14947==    by 0x35EA670F: ???


(gdb) bt
#0  0x0000000004a06318 in _vgrZU_libcZdsoZa___GI_strlen (str=0x3026bfa0 "insert into `blobtest` set `data`='pkefxxpkalpabzgrczlxefkreqljeqbvzrcnhvhsjsfnvxzjsltfuincffigdkmhvvcmnseluzgbtedrfmxvnrdmzesbinjgwvharkpgjplrlnqudfidbqwgbykupycxzyikzqincnsjrxgncqzlgyqwjdbjulztgsffxpjgymsnntdibvklwqylmwhsmdskmllxuwafabdjnwlyofknwuixiyrgnplmerfdewgizkdhznitesfqepsqbbwkdepkmjoseyxjofmmjaqdipwopfrwidmhqbtovdslvayxcnpewzhppeetblccppniamezibuoinvlxkafpcmozawtplfpepxwlwhymsuraezcwvjqzwogsozodlsfzjiyrcaljjhqwdrcjawvelhefzzaexvcbyorlcyupqwgjuamiqpiputtndjwcsuyzdfhuxswuowhrzdvriwrxqmcqthvzzzvivbabbnhdbtcfdtgssvmirrcddnytnctcvqplwytxxzxelldhwahalzxvgynaiwjyezhxqhlsqudngekocfvlbqprxqhyhwbaomgqiwkpfguohuvlnhtrsszgacxhhzeppyqwfwabiqzgyzkperiidyunrykopysvlcxwhrcboetjltawdjergalsfvaxncmzoznryumrjmncvhvxqvqhhbznnifkguuiffmlrbmgwtzvnuwlaguixqadkupfhasbbxnwkrvsfhrqanfmvjtzfqodtutkjlxfcogtsjywrdgmzgszjtsmimaelsveayqrwviqwwefeziuaqsqpauxpnzhaxjtkdfvvodniwezskbxfxszyniyzkzxngcfwgjlyrlskmrzxqnptwlilsxybuguafxxkvryyjrnkhhcmxuusitaflaiuxjhyfnzkahlgmaszujqmfdhyppdnpweqanmvzgjfyzjolbmprhnuuxextcaxzicfvsuochprmlf"...) at mc_replace_strmem.c:284
#1  0x00000000009f3d7b in fill_innodb_trx_from_cache (cache=0x1462440, thd=0x2a495000, table=0x2a422500) at /home/sbester/build/bzr/mysql-trunk/storage/innobase/handler/i_s.cc:591
#2  0x00000000009f4d7e in trx_i_s_common_fill_table (thd=0x2a495000, tables=0x2a4c3ec0) at /home/sbester/build/bzr/mysql-trunk/storage/innobase/handler/i_s.cc:1238
#3  0x00000000007689f4 in get_schema_tables_result (join=0x30f90c40, executed_place=PROCESSED_BY_JOIN_EXEC) at /home/sbester/build/bzr/mysql-trunk/sql/sql_show.cc:6745
#4  0x0000000000715a76 in JOIN::exec (this=0x30f90c40) at /home/sbester/build/bzr/mysql-trunk/sql/sql_select.cc:2861
#5  0x00000000007185be in mysql_select (thd=0x2a495000, rref_pointer_array=0x2a497590, tables=0x2a4c3ec0, wild_num=1, fields=..., conds=0x0, og_num=0, order=0x0, group=0x0, having=0x0, proc_param=0x0, select_options=2684619520, result=0x30319720, unit=0x2a496d28, select_lex=0x2a497378) at /home/sbester/build/bzr/mysql-trunk/sql/sql_select.cc:3609
#6  0x000000000070e824 in handle_select (thd=0x2a495000, lex=0x2a496c78, result=0x30319720, setup_tables_done_option=0) at /home/sbester/build/bzr/mysql-trunk/sql/sql_select.cc:319
#7  0x00000000006f2306 in execute_sqlcom_select (thd=0x2a495000, all_tables=0x2a4c3ec0) at /home/sbester/build/bzr/mysql-trunk/sql/sql_parse.cc:4557
#8  0x00000000006eaed5 in mysql_execute_command (thd=0x2a495000) at /home/sbester/build/bzr/mysql-trunk/sql/sql_parse.cc:2135
#9  0x00000000006f44ca in mysql_parse (thd=0x2a495000, rawbuf=0x30d80060 "select * from innodb_trx", length=24, parser_state=0x35ea5540) at /home/sbester/build/bzr/mysql-trunk/sql/sql_parse.cc:5597
#10 0x00000000006e864c in dispatch_command (command=COM_QUERY, thd=0x2a495000, packet=0x30bb4e31 "select * from innodb_trx", packet_length=24) at /home/sbester/build/bzr/mysql-trunk/sql/sql_parse.cc:1093
#11 0x00000000006e785f in do_command (thd=0x2a495000) at /home/sbester/build/bzr/mysql-trunk/sql/sql_parse.cc:815
#12 0x00000000006c18de in do_handle_one_connection (thd_arg=0x2a495000) at /home/sbester/build/bzr/mysql-trunk/sql/sql_connect.cc:771
#13 0x00000000006c146f in handle_one_connection (arg=0x2a495000) at /home/sbester/build/bzr/mysql-trunk/sql/sql_connect.cc:707
#14 0x00000030e1807761 in start_thread (arg=0x35ea6710) at pthread_create.c:301
#15 0x00000030e14e14ed in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:115
(gdb) frame 1
#1  0x00000000009f3d7b in fill_innodb_trx_from_cache (cache=0x1462440, thd=0x2a495000, table=0x2a422500) at /home/sbester/build/bzr/mysql-trunk/storage/innobase/handler/i_s.cc:591
591                                     row->trx_query_cs);
(gdb) list
586                     if (row->trx_query) {
587                             /* store will do appropriate character set
588                             conversion check */
589                             fields[IDX_TRX_QUERY]->store(
590                                     row->trx_query, strlen(row->trx_query),
591                                     row->trx_query_cs);
592                             fields[IDX_TRX_QUERY]->set_notnull();
593                     } else {
594                             fields[IDX_TRX_QUERY]->set_null();
595                     }