Inscrevendo o SQL Server em uma transação XA distribuída

Introdução

Por que as transações distribuídas são necessárias

XA

• Um Programa Aplicativo que define os limites da transação e especifica as ações que constituem uma transação.
• Gerenciadores de recursos, como bancos de dados ou sistemas de arquivos que fornecem acesso a recursos compartilhados.
• Um gerenciador de transações que atribui identificadores a transações, monitora seu progresso e assume a responsabilidade pela conclusão da transação e recuperação de falhas.

SQL Server e XA

O driver ODBC do Easysoft SQL Server

int ret;
SQLHANDLE hEnv, hConn;
ret = es_xa_context( NULL, &hEnv, &hConn );

OPENINFO="EASYSOFT_SQLSERVER_ODBC:DSN=SQLSERVER_SAMPLE"

EASYSOFT_SQLSERVER_ODBC:essql_xaosw:-L/usr/local/easysoft/sqlserver/lib -lessqlsrv -lodbcinst

Exemplo de aplicativo Easysoft / Tuxedo / SQL Server XA

1. Na sua máquina Tuxedo, instale o driver ODBC do SQL Server.
2. Crie uma fonte de dados do driver ODBC do SQL Server em odbc.ini. Por exemplo:

   [SQLSERVER_SAMPLE]
   Driver=Easysoft ODBC-SQL Server
   Description=Easysoft SQL Server ODBC driver
   Server=mymachine\myxaenabledinstance
   User=mydomain\myuser
   Password=mypassword
   Database=XA1

3. Crie uma tabela de amostra para o aplicativo Tuxedo:

   $ /usr/local/easysoft/unixODBC/bin/isql.sh -v SQLSERVER_SAMPLE
   SQL> CREATE TABLE [dbo].[tx_test1]([i] [int] NULL,[c] [varchar](100) NULL)

1. $ cd ~
   $ mkdir simpdir
   $ cd simpdir
   $ touch simpcl.c simpserv.c ubbsimple

2. Adicione estas linhas ao simpcl.c:

   #include <stdio.h>
   #include "atmi.h"               /* TUXEDO  Header File */
   
   
   #if defined(__STDC__) || defined(__cplusplus)
   main(int argc, char *argv[])
   #else
   main(argc, argv)
   int argc;
   char *argv[];
   #endif
   
   {
   
           char *sendbuf, *rcvbuf;
           long sendlen, rcvlen;
           int ret;
   
           if(argc != 2) {
                   (void) fprintf(stderr, "Usage: simpcl <SQL>\n");
                   exit(1);
           }
   
           /* Attach to System/T as a Client Process */
           if (tpinit((TPINIT *) NULL) == -1) {
                   (void) fprintf(stderr, "Tpinit failed\n");
                   exit(1);
           }
   
           sendlen = strlen(argv[1]);
   
           /* Allocate STRING buffers for the request and the reply */
   
           if((sendbuf = (char *) tpalloc("STRING", NULL, sendlen+1)) == NULL) {
                   (void) fprintf(stderr,"Error allocating send buffer\n");
                   tpterm();
                   exit(1);
           }
   
           if((rcvbuf = (char *) tpalloc("STRING", NULL, sendlen+1)) == NULL) {
                   (void) fprintf(stderr,"Error allocating receive buffer\n");
                   tpfree(sendbuf);
                   tpterm();
                   exit(1);
           }
   
           (void) strcpy(sendbuf, argv[1]);
   
           /* Request the service EXECUTE, waiting for a reply */
           ret = tpcall("EXECUTE", (char *)sendbuf, 0, (char **)&rcvbuf, &rcvlen, (long)0);
   
           if(ret == -1) {
                   (void) fprintf(stderr, "Can't send request to service EXECUTE\n");
                   (void) fprintf(stderr, "Tperrno = %d\n", tperrno);
                   tpfree(sendbuf);
                   tpfree(rcvbuf);
                   tpterm();
                   exit(1);
           }
   
           (void) fprintf(stdout, "Returned string is: %s\n", rcvbuf);
   
           /* Free Buffers & Detach from System/T */
           tpfree(sendbuf);
           tpfree(rcvbuf);
           tpterm();
           return(0);
   }

3. Adicione estas linhas a simpserv.c:

   #include <stdio.h>
   #include <ctype.h>
   #include <atmi.h>       /* TUXEDO Header File */
   #include <userlog.h>    /* TUXEDO Header File */
   #include <xa.h>
   #include <sql.h>
   #include <sqlext.h>
   #include <string.h>
   
   
   /* tpsvrinit is executed when a server is booted, before it begins
      processing requests.  It is not necessary to have this function.
      Also available is tpsvrdone (not used in this example), which is
      called at server shutdown time.
   */
   
   
   int tpsvrinit(int argc, char *argv[])
   {
           int ret;
   
           /* Some compilers warn if argc and argv aren't used. */
           argc = argc;
           argv = argv;
   
           /* simpapp is non-transactional, so there is no need for tpsvrinit()
              to call tx_open() or tpopen().  However, if this code is modified
              to run in a Tuxedo group associated with a Resource Manager then
              either a call to tx_open() or a call to tpopen() must be inserted
              here.
           */
   
           /* userlog writes to the central TUXEDO message log */
           userlog("Welcome to the simple server");
   
           ret = tpopen();
   
           userlog("tpopen returned %d, error=%x", ret, tperrno );
   
           return(0);
   }
   
   void tpsvrdone( void )
   {
           int ret;
   
           ret = tpclose();
   
           userlog("tpclose returned %d", ret);
   }
   
   /* This function performs the actual service requested by the client.
      Its argument is a structure containing among other things a pointer
      to the data buffer, and the length of the data buffer.
   */
   
   xa_open_entry() call.
   int es_xa_context( int* rmid, SQLHANDLE* henv, SQLHANDLE* hdbc );
   
   void EXECUTE(TPSVCINFO *rqst)
   {
           int ret;
           char *result;
           SQLHANDLE hStmt;
           char str[ 256 ];
           SQLHANDLE hEnv, hConn;
           SQLSMALLINT slen;
   
           ret = es_xa_context( NULL, &hEnv, &hConn );
   
           userlog("es_xa_context returns %d, hEnv = %p, hConn = %p", ret, hEnv, hConn );
   
           if ( ret != 0 ) {
                   result = tpalloc( "STRING", "*", 128 );
                   sprintf( result, "es_xa_context returned %d", ret );
   
                   /* Return the transformed buffer to the requestor. */
                   tpreturn(TPSUCCESS, 0, result, strlen( result ), 0);
           }
           else {
   
                   ret = tpbegin( 0, 0 );
   
                   ret = SQLAllocHandle( SQL_HANDLE_STMT, hConn, &hStmt );
   
                   ret = SQLExecDirect( hStmt, rqst -> data, rqst -> len );
   
                   ret = SQLFreeHandle( SQL_HANDLE_STMT, hStmt );
   
                   ret = tpcommit( 0 );
   
                   result = tpalloc( "STRING", "*", 128 );
                   sprintf( result, "tpcommit returns %d", ret );
   
                   /* Return the transformed buffer to the requestor. */
                   tpreturn(TPSUCCESS, 0, result, strlen( result ), 0);
           }
   }

4. Adicione estas linhas ao ubbsimple:

   *RESOURCES
   IPCKEY          123456
   
   DOMAINID        simpapp
   MASTER          simple
   MAXACCESSERS    20
   MAXSERVERS      10
   MAXSERVICES     10
   MODEL           SHM
   LDBAL           N
   
   *MACHINES
   DEFAULT:
                   APPDIR="/home/myuser/simpdir"
                   TUXCONFIG="/home/myuser/simpdir/tuxconfig"
                   TUXDIR="/home/myuser/OraHome/tuxedo12.2.2.0.0"
   
   mymachine         LMID=simple
   
   TLOGNAME=TLOG
   TLOGDEVICE="/home/myuser/simpdir/tuxlog"
   
   
   *GROUPS
   GROUP1
           LMID=simple     GRPNO=1 OPENINFO=NONE
           TMSNAME=mySQLSERVER_TMS
           OPENINFO="EASYSOFT_SQLSERVER_ODBC:DSN=SQLSERVER_SAMPLE"
   
   *SERVERS
   DEFAULT:
                   CLOPT="-A"
   
   simpserv        SRVGRP=GROUP1 SRVID=1
   
   *SERVICES
   EXECUTE

5. Defina seu ambiente:

   export TUXDIR=/home/myuser/OraHome/tuxedo12.2.2.0.0
   export TUXCONFIG=/home/myuser/simpdir/tuxconfig
   export PATH=$PATH:$TUXDIR/bin
   export LD_LIBRARY_PATH=$LD_LIBRARY_PATH:$TUXDIR/lib:/usr/local/easysoft/unixODBC/lib: \
   /usr/local/easysoft/sqlserver/lib:/usr/local/easysoft/lib

6. Crie o cliente de amostra:

   buildclient -o simpcl -f simpcl.c

   
   Se você receber o erro "referência indefinida para dlopen" ao compilar o cliente, tente este comando:
   

   buildclient -o simpcl -f "-Xlinker --no-as-needed simpcl.c"

7. Crie o servidor de amostra:

   buildserver -r EASYSOFT_SQLSERVER_ODBC -s EXECUTE -o simpserv -f "simpserv.c \
   -L/usr/local/easysoft/sqlserver/lib -lessqlsrv -lodbc"

8. Crie o arquivo TUXCONFIG para o aplicativo de amostra:

   tmloadcf ubbsimple

9. Crie um dispositivo de log Tuxedo para o aplicativo de amostra:

   $ tmadmin -c
   > crdl -z /home/myuser/simpdir/tuxlog -b 512

10. Crie um gerenciador de transações Tuxedo que faça interface com o driver ODBC do SQL Server:

    $ buildtms -o mySQLSERVER_TMS -r EASYSOFT_SQLSERVER_ODBC

11. Inicie o servidor de amostra:

    $ tmboot

12. Teste o aplicativo de amostra:

    ./simpcl "insert into tx_test1 values( 1, 'hello world' )"
    /usr/local/easysoft/unixODBC/bin/isql.sh -v SQLSERVER_SAMPLE
    SQL> select * from tx_test1
    +------------+--------------+
    | i          | c            |                                                                                                   
    +------------+--------------+
    | 1          | hello world  |                                                                                         
    +------------+--------------+

13. Se você vir os dados na tabela do SQL Server, desligue o servidor de amostra:

    tmshutdown

    
    Caso contrário, consulte ULOG.nnn no diretório de aplicativos de amostra.