Hi Tony,

I fixed this in https://jira.mariadb.org/browse/MDEV-19274 .

I do not think it makes a lot of sense to implement generic, poll()-based threadpool . epoll-like APIs exists almost everywhere, except  very exotic (for MariaDB) platforms we do not build on.

I googled, and I found that AIX has  Windows-like IOCP with GetQueuedCompletionStatus/CreateIoCompletionPort etc. Maybe, it does not behave exactly like on Windows, but perhaps you can figure out what’s the difference and  what is required to port that code.

Regards,

Wlad

From: REIX, Tony
Sent: Tuesday, 16 April 2019 11:26
To: maria-developers@lists.launchpad.net
Subject: [Maria-developers] MariaDB 10.4 on AIX. Issue with: HAVE_POOL_OF_THREADS

Hi,

In my environment (AIX & MariaDB v10.4.3 or 10.4.4), I have an issue with HAVE_POOL_OF_THREADS.

When building, I have the following trace and error (full line of g++ compilation at end of email) :

[ 44%] Linking CXX executable explain_filename-t
/opt/freeware/bin/cmake -E cmake_link_script CMakeFiles/explain_filename-t.dir/link.txt --verbose=1
/opt/freeware/bin/g++ ...........  -o explain_filename-t ....
ld: 0711-317 ERROR: Undefined symbol: .TP_pool_generic::TP_pool_generic()
ld: 0711-317 ERROR: Undefined symbol: .TP_pool_generic::init()

This seems to be due to the following lines of the file:
sql/CMakeLists.txt :

  IF (CMAKE_SYSTEM_NAME MATCHES "Linux" OR
      CMAKE_SYSTEM_NAME MATCHES "Windows" OR
      CMAKE_SYSTEM_NAME MATCHES "SunOS" OR
      HAVE_KQUEUE)
   ADD_DEFINITIONS(-DHAVE_POOL_OF_THREADS)
   IF(WIN32)
     SET(SQL_SOURCE ${SQL_SOURCE} threadpool_win.cc)
   ENDIF()
   SET(SQL_SOURCE ${SQL_SOURCE} threadpool_generic.cc)
  ENDIF()

In case the Operating System is not Linux, Windows, or SunOS, then there is NO  -DHAVE_POOL_OF_THREADS  and the file: threadpool_generic.cc is NOT compiled.

However, the C++ code of MariaDB still looks at least for 2 routines of threadpool_generic.cc  :
  TP_pool_generic::TP_pool_generic()
  TP_pool_generic::init()
but these routines are not available since threadpool_generic.cc was not compiled.

So, in my opinion, there are some #ifdef HAVE_POOL_OF_THREADS  lines that are missing in common threadpool code that would prevent to use threadpool generic routines.
However, I do not master this code.


Why not implement on AIX the generic pool of thread and thus add AIX to the above IF( ) test of sql/CMakeLists.txt ??
The reason if that, out of the 4 possibilities listed in sql/threadpool_generic.cc : epoll, KQUEUE, port, and IOCP, none of them are available on AIX with the EXACT required behavior. We have to implement something miming epoll(), we think. Before fixing this performance improvement, we'd like to be able to build & test MariaDB for all its other features.

sql/threadpool_generic.cc :
  #ifdef __linux__
    #include <sys/epoll.h>
    typedef struct epoll_event native_event;
  #elif defined(HAVE_KQUEUE)
    #include <sys/event.h>
    typedef struct kevent native_event;
  #elif defined (__sun)
    #include <port.h>
    typedef port_event_t native_event;
  #elif defined (HAVE_IOCP)
    typedef OVERLAPPED_ENTRY native_event;
  #else
  #error threadpool is not available on this platform          <<---- AIX
  #endif


Regards,

Tony


/opt/freeware/bin/g++
        -O2
        -g
        -L/opt/freeware/lib64
        -D_GNU_SOURCE
        -D_FILE_OFFSET_BITS=64
        -D_LARGEFILE_SOURCE
        -maix64
        -Wl,-bbigtoc
        -fPIC
        -O2
        -g
        -L/opt/freeware/lib64
        -D_GNU_SOURCE
        -D_FILE_OFFSET_BITS=64
        -D_LARGEFILE_SOURCE
        -maix64
        -Wl,-bbigtoc
        -fPIC
        -pie
        -fPIC
        -fno-rtti
        -O3
        -g
        -static-libgcc
        -fno-omit-frame-pointer
        -fno-strict-aliasing
        -Wno-uninitialized
        -D_FORTIFY_SOURCE=2
        -DDBUG_OFF
        -Wl,-blibpath:/opt/freeware/lib:/opt/freeware/lib64:/usr/lib:/lib
        -lpgport
        CMakeFiles/explain_filename-t.dir/explain_filename-t.cc.o
        -o
        explain_filename-t
        -Wl,-bnoipath
        -Wl,-blibpath:/opt/freeware/lib64:/opt/freeware/lib/gcc/powerpc-ibm-aix7.2.0.0/8.2.0/ppc64:/opt/freeware/lib/ppc64:/opt/freeware/lib/gcc/powerpc-ibm-aix7.2.0.0/8.2.0:/opt/freeware/lib:/usr/lib:/lib
        -lpthreads
        ../../sql/libsql.a
        ../mytap/libmytap.a
        ../../storage/archive/libarchive.a
        ../../storage/blackhole/libblackhole.a
        ../../storage/csv/libcsv.a
        ../../storage/federatedx/libfederatedx.a
        ../../storage/heap/libheap.a
        ../../storage/innobase/libinnobase.a
        -llz4
        ../../storage/maria/libaria.a
        ../../storage/myisam/libmyisam.a
        ../../storage/myisammrg/libmyisammrg.a
        ../../storage/sequence/libsequence.a
        ../../plugin/feedback/libfeedback.a
        ../../plugin/user_variables/libuser_variables.a
        ../../plugin/userstat/libuserstat.a
        ../../sql/libpartition.a
        ../../sql/libsql_sequence.a
        ../../mysys/libmysys.a
        ../../mysys_ssl/libmysys_ssl.a
        ../../dbug/libdbug.a
        ../../mysys/libmysys.a
        ../../mysys_ssl/libmysys_ssl.a
        ../../dbug/libdbug.a
        /usr/lib64/libz.so
        -lm
        ../../extra/yassl/libyassl.a
        ../../extra/yassl/taocrypt/libtaocrypt.a
        ../../strings/libstrings.a
        ../../vio/libvio.a
        ../../pcre/libpcre.a
        ../../wsrep-lib/src/libwsrep-lib.a
        -lpthread
        -ldl
        ../../wsrep-lib/wsrep-API/libwsrep_api_v26.a
        -lpthreads

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