Hi, Sachin! Great work!
On Mar 27, Sachin Setiya wrote: > revision-id: 710756527ec8589bce33bc834a1d8e6604266b6d > (mariadb-10.1.31-47-g7107565) > parent(s): 8152c52e1af608da5d288a4e6fc82e2d804e64cd > author: Sachin Setiya > committer: Sachin Setiya > timestamp: 2018-03-27 04:24:57 +0530 > message: > > MDEV-10259 mysqld crash with certain statement length and... > order with Galera and encrypt-tmp-files=1 > > Problem:- If trans_cache (IO_CACHE) uses encrypted tmp file > then on next DML server will crash. > > Case:- > Lets take a case , we have a table t1 , We try to do 2 inserts in t1 > 1. A really long insert so that trans_cache has to use temp_file > 2. Just a small insert > > Analysis:- Actually server crashes from inside of galera > library. > /lib64/libc.so.6(abort+0x175)[0x7fb5ba779dc5] > /usr/lib64/galera/libgalera_smm.so(_ZN6galera3FSMINS_9TrxHandle5State... > mysys/stacktrace.c:247(my_print_stacktrace)[0x7fb5a714940e] > sql/signal_handler.cc:160(handle_fatal_signal)[0x7fb5a715c1bd] > sql/wsrep_hton.cc:257(wsrep_rollback)[0x7fb5bcce923a] > sql/wsrep_hton.cc:268(wsrep_rollback)[0x7fb5bcce9368] > sql/handler.cc:1658(ha_rollback_trans(THD*, bool))[0x7fb5bcd4f41a] > sql/handler.cc:1483(ha_commit_trans(THD*, bool))[0x7fb5bcd4f804] > > but actual issue is not in galera but in mariadb, because for 2nd > insert we should never call rollback. We are calling rollback because > log_and_order fails it fails because write_cache fails , It fails > because after reinit_io_cache(trans_cache) , my_b_tell says 0 so we > look into tmp_file for data , which is obviously wrong since temp > was used for previous insert and it no longer exist. Add here something like: wsrep_write_cache_inc() reads the IO_CACHE in a loop, filling it with my_b_fill() until it returns "0 bytes read". Later MYSQL_BIN_LOG::write_cache() does the same. wsrep_write_cache_inc() assumes that reading a zero bytes past EOF leaves the old data in the cache. Let's do that. > diff --git a/sql/mf_iocache_encr.cc b/sql/mf_iocache_encr.cc > index 149e6fe..41e1333 100644 > --- a/sql/mf_iocache_encr.cc > +++ b/sql/mf_iocache_encr.cc > @@ -49,8 +49,7 @@ static int my_b_encr_read(IO_CACHE *info, uchar *Buffer, > size_t Count) > > if (pos_in_file == info->end_of_file) > { here, a comment: /* reading past EOF should not empty the cache */ > - info->read_pos= info->read_end= info->buffer; > - info->pos_in_file= pos_in_file; > + info->read_pos= info->read_end; > info->error= 0; > DBUG_RETURN(MY_TEST(Count)); > } and add a test for it into unittest/sql/mf_iocache-t.cc. Something simple, like, write into a cache, reinit to READ, fill, fill, reinit to READ, verify the data is still there. Regards, Sergei Chief Architect MariaDB and secur...@mariadb.org _______________________________________________ Mailing list: https://launchpad.net/~maria-developers Post to : maria-developers@lists.launchpad.net Unsubscribe : https://launchpad.net/~maria-developers More help : https://help.launchpad.net/ListHelp