maria-developers team mailing list archive

[Sergei Golubchik <serg@xxxxxxxxxxx>]

Hi, knizhnik!

On Jun 17, knizhnik wrote:
> Hi,
> 
> I wonder what is the simplest way to execute SQL query inside server?
> In PostgreSQL there is SPI API, SQLite allows to use client API,...
> but I failed to find right way of running queries inside mySQL server.

There is no API for that at the moment.

> My task is the following: I want to patch mySQL server by redirecting
> execution of some queries to some external executor.  The text of this
> queries will be stored inside database in some special table.  So when
> some query is executed by mySQL server, I want to perform lookup in
> this table.  What is the simplest way to do it in mySQL?

There are many examples for that in the code, but they all use low-level
API. The typical sequence for your use case is:

  prepare a TABLE_LIST structure
  open_and_lock_tables()
  ha_index_read_idx_map()
  read values using Field methods

Something alike is done in sql_acl.cc (loading privileges), in sql_help.cc,
sp.cc (stored routines), event_db_repository.cc, sql_plugin.cc,
sql_udf.cc, tztime.cc (time zones), etc.

Regards,
Sergei
Chief Architect MariaDB
and security@xxxxxxxxxxx