mariadb/storage/federatedx
Nikita Malyavin 21809f9a45 MDEV-17556 Assertion `bitmap_is_set_all(&table->s->all_set)' failed
The assertion failed in handler::ha_reset upon SELECT under
READ UNCOMMITTED from table with index on virtual column.

This was the debug-only failure, though the problem is mush wider:
* MY_BITMAP is a structure containing my_bitmap_map, the latter is a raw
 bitmap.
* read_set, write_set and vcol_set of TABLE are the pointers to MY_BITMAP
* The rest of MY_BITMAPs are stored in TABLE and TABLE_SHARE
* The pointers to the stored MY_BITMAPs, like orig_read_set etc, and
 sometimes all_set and tmp_set, are assigned to the pointers.
* Sometimes tmp_use_all_columns is used to substitute the raw bitmap
 directly with all_set.bitmap
* Sometimes even bitmaps are directly modified, like in
TABLE::update_virtual_field(): bitmap_clear_all(&tmp_set) is called.

The last three bullets in the list, when used together (which is mostly
always) make the program flow cumbersome and impossible to follow,
notwithstanding the errors they cause, like this MDEV-17556, where tmp_set
pointer was assigned to read_set, write_set and vcol_set, then its bitmap
was substituted with all_set.bitmap by dbug_tmp_use_all_columns() call,
and then bitmap_clear_all(&tmp_set) was applied to all this.

To untangle this knot, the rule should be applied:
* Never substitute bitmaps! This patch is about this.
 orig_*, all_set bitmaps are never substituted already.

This patch changes the following function prototypes:
* tmp_use_all_columns, dbug_tmp_use_all_columns
 to accept MY_BITMAP** and to return MY_BITMAP * instead of my_bitmap_map*
* tmp_restore_column_map, dbug_tmp_restore_column_maps to accept
 MY_BITMAP* instead of my_bitmap_map*

These functions now will substitute read_set/write_set/vcol_set directly,
and won't touch underlying bitmaps.
2021-01-27 00:50:55 +10:00
..
AUTHORS Lintian complains on spelling error 2019-12-02 12:41:13 +02:00
ChangeLog Added federatedx storage engine 2009-10-30 20:50:56 +02:00
CMakeLists.txt CRLF->LF 2015-06-02 22:07:47 +02:00
FAQ Added federatedx storage engine 2009-10-30 20:50:56 +02:00
federatedx_io.cc Remove unused declarations 2019-04-03 19:46:34 +03:00
federatedx_io_mysql.cc Merge branch '10.2' into 10.3 2020-12-23 19:28:02 +01:00
federatedx_io_null.cc Merge branch '10.2' into 10.3 2020-12-23 19:28:02 +01:00
federatedx_probes.h Added federatedx storage engine 2009-10-30 20:50:56 +02:00
federatedx_txn.cc MDEV-12725 select on federated table crashes server 2017-08-08 22:49:09 +02:00
ha_federatedx.cc MDEV-17556 Assertion `bitmap_is_set_all(&table->s->all_set)' failed 2021-01-27 00:50:55 +10:00
ha_federatedx.h Merge branch '10.2' into 10.3 2020-12-23 19:28:02 +01:00
README Added federatedx storage engine 2009-10-30 20:50:56 +02:00
README.windows CRLF->LF 2015-06-02 22:07:47 +02:00
TODO Added federatedx storage engine 2009-10-30 20:50:56 +02:00

This is the FederatedX Storage Engine, developed as an external storage engine.

NOTE:

The following is only relevant if you use it for MySQL.  MariaDB already comes
with the latest version of FederatedX.

To install, grab a copy of the mysql source code and run this:

./configure --with-mysql=/path/to/src/mysql-5.x --libdir=/usr/local/lib/mysql/

make install

And then inside of MySQL:

mysql> INSTALL PLUGIN federatedx SONAME 'libfederatedx_engine.so';

mysql> CREATE TABLE `d` (`a` varchar(125), b text, primary key(a)) ENGINE=FEDERATEDX CONNECTION="mysql://root@host/schema/table"

or 

mysql> CREATE TABLE `d` (`a` varchar(125), b text, primary key(a)) ENGINE=FEDERATEDX CONNECTION="server" CHARSET=latin1;

You will probably need to edit the Makefile.am in the src/ tree if you want
to build on anything other then Linux (and the Makefile assumes that the
server was not compiled for debug). The reason for the two possible
configure lines is that libdir is dependent on where MySQL was installed. If
you run the "INSTALL PLUGIN ..." and you get a file not found, check that
your configured this directory correctly.

For Solaris you can enable DTrace probes by adding to configure
--enable-dtrace