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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_bytes_in_cache 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. 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 Solution:- There is two issue in my_b_encr_read 1st we should never equal read_end to info->buffer. I mean this does not make sense read_end should always point to end of buffer. 2nd For most of the case(apart from async IO_CACHE) info->pos_in_file should be equal to info->buffer position wrt to temp file , since in this case we are not changing info->buffer it should remain unchanged.
Unit tests directory structure
------------------------------
This is the current structure of the unit tests. More directories
will be added over time.
mytap Source for the MyTAP library
mysys Tests for mysys components
bitmap-t.c Unit test for MY_BITMAP
base64-t.c Unit test for base64 encoding functions
examples Example unit tests.
core-t.c Example of raising a signal in the middle of the test
THIS TEST WILL STOP ALL FURTHER TESTING!
simple-t.c Example of a standard TAP unit test
skip-t.c Example where some test points are skipped
skip_all-t.c Example of a test where the entire test is skipped
todo-t.c Example where test contain test points that are TODO
no_plan-t.c Example of a test with no plan (avoid this)
Executing unit tests
--------------------
To make and execute all unit tests in the directory:
make test
Observe that the tests in the examples/ directory are just various
examples of tests and are not expected to pass.
Adding unit tests
-----------------
Add a file with a name of the format "foo-t.c" to the appropriate
directory and add the following to the Makefile.am in that directory
(where ... denotes stuff already there):
noinst_PROGRAMS = ... foo-t
Note, it's important to have "-t" at the end of the filename, otherwise the
test won't be executed by 'make test' !
Documentation
-------------
The generated documentation is temporarily placed at:
http://www.kindahl.net/mytap/doc/
I will move it to a better place once I figure out where and how.