Re: (ITS#7829) MDB mdb_cursor_del causes records to be skipped

[hyc@symas.com]

Hallvard Breien Furuseth wrote:
> Sorry, forgot the crash info.

Thanks, confirmed. In a nested rebalance, doing a page merge with the neighbor 
on the left was discarding the rebalanced state. Fixed now in mdb.master
>
> mdb.c:7419: Assertion 'NUMKEYS(mc->mc_pg[ptop]) > 1' failed in mdb_rebalance()
>
> (gdb) p *mc->mc_pg[ptop]
> $1 = {
>    mp_p = {p_pgno = 24, p_next = 0x18}, mp_pad = 0, mp_flags = 17,
>    mp_pb = {pb = {pb_lower = 18, pb_upper = 1016}, pb_pages = 66584594},
>    mp_ptrs = {1016}
> }
> (gdb) info locals
> node = 0x0
> rc = -268443168
> ptop = 0
> minkeys = 1
> mn = {
>    mc_next = 0x7ffff5ce0010, mc_backup = 0x7fffe41013a0, mc_xcursor = 0x0,
>    mc_txn = 0x7fffe42c9700, mc_dbi = 6, mc_db = 0x7fffe42c9890,
>    mc_dbx = 0x7fffe42c3fb0, mc_dbflag = 0x7fffe42c3fb0 "\002",
>    mc_snum = 2, mc_top = 1, mc_flags = 65,
>    mc_pg = {0x7fffe4102840, 0x7fffe8109670, 0x2efffe300, 0x7fffefffe0c0, 0x7fffefffe0a0, 0x7fffefffe2c0,
>      0x7fffefffe2c0, 0x53e7cd, 0x7fffefffe1c0, 0x7fffe40019f0, 0x7fffe41013a0, 0x7fffefffe2c0, 0x30c3669909,
>      0xfbad8001, 0x7fffefffe2c0, 0x7fffefffe2c0, 0x7fffefffe2c0, 0x7fffefffe130, 0x7fffefffe2d0, 0x7fffefffe180,
>      0x49c7ca, 0x7fffefffe140, 0x7fffefffe1dc, 0x1100000000, 0x0, 0x7fffefffe2d0, 0x7fffe4101528, 0x7fffefffe180, 0x1,
>      0x7fffe81099d4, 0x7fffefffe260, 0x100000008},
>    mc_ki = {5416, 58384, 32767, 0, 39380, 59408, 32767, 0, 39364, 59408, 32767, 0, 39400, 59408, 32767, 0, 39332,
>      59408, 32767, 0, 68, 0, 0, 0, 15369, 50024, 48, 0, 57792, 61439, 32767, 0}
> }
> oldki = 0
> __FUNCTION__ = "mdb_rebalance"
> (gdb) p *mc
> $2 = {
>    mc_next = 0x0, mc_backup = 0x0, mc_xcursor = 0x7fffe4101528,
>    mc_txn = 0x7fffe42c9700, mc_dbi = 6, mc_db = 0x7fffe42c9890,
>    mc_dbx = 0x7fffe42c3fb0, mc_dbflag = 0x7fffe42cb3e6 "\t\n\n",
>    mc_snum = 2, mc_top = 1, mc_flags = 65,
>    mc_pg = {0x7fffe4102840, 0x7fffe8109670, 0x0, 0x40, 0x44, 0x0, 0x6a206e616d726568, 0x6f65703d756f2c72,
>      0x653d63642c656c70, 0x642c656c706d6178, 0x302e006d6f633d63, 0x30235a3632353631, 0x2d1, 0x7fffe4000338, 0x81,
>      0x7fffe4102c40, 0x7fffe42c7860, 0x20, 0x64, 0x0, 0x4, 0x1a, 0x19, 0x10, 0xe, 0xd, 0xb, 0xa, 0x9, 0x140, 0x84,
>      0x0},
>    mc_ki = {0, 5, 0, 0, 22160, 63214, 32767, 0, 32769, 0, 0, 0, 64592, 70, 0, 0, 22160, 63214, 32767, 0, 32775, 0, 0,
>      0, 63424, 70, 0, 0, 22160, 63214, 32767, 0}
> }
>
> Backtrace:
> #2  mdb_assert_fail ()
> #3  mdb_rebalance (mc=0x7fffe41013a0) at mdb.c:7419
> #4  mdb_cursor_del0 (mc=0x7fffe41013a0) at mdb.c:7496
> #5  mdb_cursor_del (mc=0x7fffe41013a0, flags=0) at mdb.c:6360
> #6  mdb_idl_delete_keys (be, cursor=0x7fffe41013a0, keys, id=7) at idl.c:608
> #7  indexer (op=0x7fffe4000950, txn, ai, ad=0x838180, atname=0x837fc8, vals=0x7fffe40019f0, id=7, opid=2, mask=1814) at index.c:258
> #8  index_at_values (op=0x7fffe4000950, txn=0x7fffe42c9700, ad, type=0x837f60, tags=0x8381a0, vals=0x7fffe40019f0, id=7, opid=2) at index.c:337
> #9  mdb_index_values (op, txn, desc, vals, id, opid) at index.c:386
> #10 mdb_index_entry (op=0x7fffe4000950, txn=0x7fffe42c9700, opid=2, e=0x7fffe40017d0) at index.c:558
> #11 mdb_delete (op=0x7fffe4000950, rs=0x7fffefffe910) at delete.c:347
> #12 overlay_op_walk (op=0x7fffe4000950, rs=0x7fffefffe910, which=op_delete, oi=0x7fffe81036a0, on=0x0) at backover.c:671
> #13 over_op_func (op=0x7fffe4000950, rs, which) at backover.c:723
> #14 fe_op_delete (op=0x7fffe4000950, rs=0x7fffefffe910) at delete.c:174
> #15 do_delete (op=0x7fffe4000950, rs=0x7fffefffe910) at delete.c:95
> #16 connection_operation (ctx=0x7fffefffea70, arg_v=0x7fffe4000950) at connection.c:1155
> #17 connection_read_thread (ctx=0x7fffefffea70, argv) at connection.c:1291
> #18 ldap_int_thread_pool_wrapper (xpool=0x83b3b0) at tpool.c:688
>
> Test output:
> Running ldapadd to build slapd config database...
> Running ldapadd to build slapd database...
> Search the entire database...
> Running ldapmodify to add a member...
> Re-search the entire database...
> Running ldapmodify to rename a member...
> Re-search the entire database...
> Running ldapmodify to rename a group...
> Re-search the entire database...
> Running ldapmodify to add self...
> Re-search the entire database...
> Running ldapdelete to remove a member...
> Re-search the entire database...
> Running ldapdelete to remove a group...
> Re-search the entire database...
> Adding groups with MAY member type schemas...
>
> Log ends with:
> 533898e1 => index_entry_del( 7, "cn=Jessica Rabbit,ou=People,dc=example,dc=com" )
> 533898e1 mdb_idl_delete_keys: 7 [860433ad]
> 533898e1 mdb_idl_delete_keys: 7 [00000000]
> 533898e1 mdb_idl_delete_keys: 7 [aaacba45]
> 533898e1 mdb_idl_delete_keys: 7 [e10d2617]
>


-- 
   -- Howard Chu
   CTO, Symas Corp.           http://www.symas.com
   Director, Highland Sun     http://highlandsun.com/hyc/
   Chief Architect, OpenLDAP  http://www.openldap.org/project/