If you have a merge tree, you merge into MariaDB as follows:

1. MariaDB merge trees are in the mergetrees repository. Add it as a new remote:

   git remote add merge https://github.com/MariaDB/mergetrees

2. Check out the branch you want to update and merge, for example:

   git checkout merge-innodb-5.6

3. delete everything in the branch
4. download the latest released source tarball, unpack it, copy files into the repository:
   • for InnoDB-5.6: use the content of the storage/innobase/ of the latest MySQL 5.6 source release tarball.
   • for performance schema 5.6: use storage/perfschema, include/mysql/psi, mysql-test/suite/perfschema, and mysql-test/suite/perfschema_stress from the latest MySQL 5.6 source release tarball.
   • for SphinxSE: use mysqlse/ subdirectory from the latest Sphinx source release tarball.
   • for XtraDB: use the content of the storage/innobase/ of the latest Percona-Server source release tarball (5.5 or 5.6 as appropriate).
   • for pcre: simply unpack the latest pcre release source tarball into the repository, rename pcre-X-XX/ to pcre.
5. Now git add ., git commit (use the tarball version as a comment), git push
6. merge this branch into MariaDB
7. Sometimes after a merge, some changes may be needed:
   • for performance schema 5.6: update storage/perfschema/ha_perfschema.cc, plugin version under maria_declare_plugin.
   • for InnoDB-5.6: update storage/innobase/include/univ.i, setting INNODB_VERSION_MAJOR, INNODB_VERSION_MINOR, INNODB_VERSION_BUGFIX to whatever MySQL version you were merging from.
   • for XtraDB-5.5: update storage/xtradb/include/univ.i, setting PERCONA_INNODB_VERSION, INNODB_VERSION_STR to whatever Percona-Server version you were merging from.
   • for XtraDB-5.6: update storage/xtradb/include/univ.i, setting PERCONA_INNODB_VERSION, INNODB_VERSION_MAJOR, INNODB_VERSION_MINOR, INNODB_VERSION_BUGFIX to whatever Percona-Server version you were merging from.