lr.c

extremeDB s sample code,useful for you

/***************************************************************
 *                                                             *
 * Copyright (c) 2001-2006 McObject LLC. All Right Reserved.   *
 *                                                             *
 ***************************************************************/
#include <platform.h>
#include <mco.h>
#include <mcolog.h>
#include "lrdb.h" 

/* logging related defines */
#define  LOG_MAX_FILESIZE       1024*64
#define  LOG_MAX_FILES_IN_DIR   2  //256

#if defined (_VXWORKS)
  #define  LOG_FILEPATH           "/tgtsvr/lr_logs"
#elif defined (_WIN32_WCE)
  #define  LOG_FILEPATH           "lr_logs"
#else
  #define  LOG_FILEPATH           "lr_logs"
#endif

/* common defines */
#define MAP_ADDRESS 0x20000000
const char      * dbname	= "lrdb";
const int       SEGSZ		= 1024 * 512;
#ifndef MCO_PLATFORM_X64
const uint2     PAGESIZE        = 96;
#else
const uint2     PAGESIZE        = 192;
#endif

void            * start_mem = (void*)MAP_ADDRESS;
mco_db_h        db;
static  mco_runtime_info_t info;
static  unsigned char	deferred_deletion_mode = 1;
static  unsigned char	slave_flag      = 1;
static  unsigned int	thread_num      = 1;
static  unsigned int	mode_flags      = 0;
static  int           flush_depth;
static  int           flush_time;
static	int			  test_Mode = 0;
THREAD_ID_T 	td  = (THREAD_ID_T)INVALID_HANDLE_VALUE;

#define NUMB_OF_ITEMS		1000
#define MAX_STRING_LENGTH	100

void help(void)
{
  
  printf ("Usage:        log [OPTIONS]\n\n");

  
  printf ("Description:  This sample demonstrates the eXtremeDB Transaction Logging.\n"
                      "              While populating the database, the sample application calcu-\n"
                  "              lates the data checksum. The application can be terminated\n"
                      "              \"normally\" by pressing \"Enter\", or \"abnormally\" by press-\n"
                      "              ing \"Ctrl-C\" in the console window.\n"  
                      "              In any case the log files are kept on disk, and when restarted\n"
                      "              the sample application attempts to recover the database.\n"
                      "              After the recovery is complete, the checksum of the new database\n"
                      "              is compared with the checksum of the old one.\n\n");

  printf ("Options:\n\n");
  printf ("-m            Runs as a \"main database process\" -- creates the database\n"
          "              and performs the recovery from the log files\n\n");

  printf ("-s            Demonstrates the \"multi-process\" database access mode. Runs as\n"
          "              a \"supplementary\" process: it connects to the existing database,\n"
                "              but does not create the database and does not perform the\n"
          "              recovery\n\n");

  printf ("-d            Demonstrates the \"deferred deletion\" API\n\n");
  
  printf ("-w[I]         Demonstrates multi-threaded access to the database. Creates a \n"
                "              number of working threads each with the separate database\n"
          "              connection.\n"
          "              The number of threads I = 1 - 9. Default is 1 thread\n\n");
  
  printf ("Buffering:    File buffering options. The runtime typically writes data to an\n"
          "              internal buffer that the operating system writes to disk on a\n"
          "              regular basis. The following options specify how often the\n"
          "              runtime clears the buffers for the log file and causes all\n"
          "              buffered data to be written to disk.\n\n"); 

  printf ("-f[I]         Instructs the runtime to flush log file buffers after a number\n"
          "              of commited transactions (transaction queue depth)\n\n" 
                "              \"I\" specifies the number of transactions in the queue.\n"
          "              The default depth is 1 (flush buffers after each transaction)\n\n");
  
  printf ("-t[I]         Instructs the runtime to flush buffers every \"I\" milliseconds\n"
                "              The default is 100 milliseconds\n\n");
  
  printf ("-n            Runs in \"non-buffered\" mode\n");

  printf ("-h            help\n\n");
}

void usage(void)
{
  printf ("Usage:  log [-d]\n"
          "            [-m]\n"
          "            [-s]\n"
          "            [-w [number_of_working_threads] ]\n"
          "            [-f [transaction_depth] ]\n"
          "            [-t [milliseconds] ]\n"
          "            [-n]\n"
          "            [-h]\n\n");
}

void _SH_(void)
{
	printf("\neXtremeDB runtime version %d.%d, build %d\n\n",
		MCO_COMP_VER_MAJOR, MCO_COMP_VER_MINOR, MCO_COMP_BUILD_NUM);
}

/* random related stuff */
double rrand(double range) {
	return (((double)rand()) / ((double)RAND_MAX) ) * (range-1.0);
};
/* generate random string having random length*/
char* rand_string() {
	int l = (int)rrand(MAX_STRING_LENGTH)+1;
	int i;
	char* pc = (char*)malloc(l+1);
	for (i=0;i<l;i++) {
		pc[i] = 'a'+(char)rrand(26);
	};
	pc[l] = 0;
	return pc;
};


/* eXtremeDB fatal error handler */
static void errhandler( int n )
{
	Printf( "\n*** eXtremeDB runtime fatal error: %d\n", n );
	EXIT( -1 );
};


/* initialize the database */
void init_database() {
	MCO_RET	rc;

	Printf( "Starting up the database");
	
	/* alloc memory for the database */
	mco_get_runtime_info( &info);
	
	if ( info.mco_shm_supported == 0 ) {
	    start_mem = (void*)malloc( SEGSZ );
	    if ( start_mem == 0 ) {
		Printf( "Unable to allocate amount of memory\n");
		EXIT(-1);
	    };
	};
	Printf( "." );
	
	/* start the eXtremeDB engine and setup fatal error handler */
	mco_runtime_start();
	mco_error_set_handler( &errhandler );
	Printf( "." );

	/* make the database */
        if(slave_flag == 1) {
	  mco_db_kill(dbname);
	  rc = mco_db_open( dbname, lrdb_get_dictionary(), start_mem, SEGSZ, PAGESIZE );
	  if ( rc ) {
	    Printf ( "Couldn't open database: %d\n",rc);
	    mco_runtime_stop();
	    EXIT( -1 );
	  }
        }

	Printf( "." );
	
	/* connect to the database */

        if ( (rc = mco_db_connect( dbname, &db )) != MCO_S_OK) {
  	  Printf("Error connecting to database %d", rc);
          EXIT(-1);
        }

	Printf( "." );
	
	Printf( "Done\n" );
};

/* clean the database */
void free_database() {

	Printf( "\nCleaning up the database");
	
	/* disconnect and close the database */
	mco_db_disconnect( db );
	Printf( "." );
		
	mco_db_close( dbname );
	Printf( "." );
		
	/* stop eXtremeDB engine */
	mco_runtime_stop();
	Printf( "." );
		
	/* cleanup */
	if ( info.mco_shm_supported == 0 ) {
		free(start_mem);
	};
	
	Printf( "Done\n" );
};

/* create an object */
MCO_RET make_an_object ( mco_trans_h t, unsigned int index ) {

	MCO_RET			rc = MCO_S_OK;
	Obj 			obj;
	
	/* make an object */
	if ( MCO_S_OK == ( rc = Obj_new( t, &obj))) {
	
	  char *ps = rand_string();
	  
	  /* and fill it up */
	  Obj_index_put( &obj, index );
	  Obj_value_put( &obj, ps, (uint2)strlen(ps) );
	  
	  rc = Obj_checkpoint( &obj );
	};
	
	return rc;
};

/* fill up the database */
MCO_RET populate_database () {

	unsigned int 	i;
	MCO_RET			rc = MCO_S_OK;
	mco_trans_h 	t;

	Printf( "Populating the database");
	
	/* makes a lot of objects */
	for ( i=0 ; rc == MCO_S_OK && i < NUMB_OF_ITEMS; i++ ) {
	
	  if ( i % 100 == 0 ) {
		  Printf( "." );
		  Sleep(10);
	  };
  
	  /* open a transaction */
	  if ( MCO_S_OK != (rc = mco_trans_start( db, MCO_READ_WRITE, MCO_TRANS_FOREGROUND, &t ) )) {
		  /* error */
		  Printf( "Unable to start a transaction\n");
	  } else { /* OK */
	  
	      /* make an object */
	      if ( MCO_S_OK == (rc = make_an_object( t, i ))) {
	      
		      /* commit transaction */
		      rc = mco_trans_commit( t );
		      
	      } else {
	      
		      /* rollback transaction */
		      mco_trans_rollback( t );
	      };
	  };
	};
	
	if ( rc != 0 ) {
		Printf( "Error: %d\n", rc);
	} else {
		Printf( "Done\n" );
	};
	
	return rc;
};

/* show the database info */
void show_db_info () {
	mco_puint		mn, mx, fp, tp;
	MCO_RET			rc = MCO_S_OK;
	mco_trans_h 	t;
	mco_cursor_t	c;
	Obj 			obj;
	char 			buf[MAX_STRING_LENGTH+1], 
					*p;
	uint2 			len;
	unsigned int 	checksum = 0;
	
	/* open a transaction */
	if ( MCO_S_OK != (rc = mco_trans_start( db, MCO_READ_ONLY, MCO_TRANS_FOREGROUND, &t ) )) {
		/* error */
		Printf( "Unable to start a transaction\n");
		
	} else { /* OK */

	  /* open index cursor */
	  if ( MCO_S_OK != (rc=Obj_index_index_cursor( t, &c ))) {
		  /* error */
		  Printf( "Unable to open a cursor\n");
	  } else {

	      /* get memory status */
	      mco_db_free_pages   ( db, &fp );
	      mco_db_total_pages  ( db, &tp );

	      /* get first index */
	      mco_cursor_first( t, &c );
	      Obj_from_cursor( t, &c, &obj );
	      Obj_index_get( &obj, &mn );
		      
	      /* calculate the checksum of the database */
	      do {
		/* get the string field */
		Obj_from_cursor( t, &c, &obj );
		Obj_value_get( &obj, buf, sizeof(buf), &len );
			
		/* sum the field's chars */
		p = buf;
		while ( *p ) {
			checksum += *p;
			p++;
		};
		      
	      } while ( mco_cursor_next( t, &c ) == MCO_S_OK ) ;
		      
	      /* get last index */
	      mco_cursor_last( t, &c );
	      Obj_from_cursor( t, &c, &obj );
	      Obj_index_get( &obj, &mx );
		      
	      /* show the information */
#if (defined (_VXWORKS) && (CPU==SIMNT)) || defined(_WIN32_WCE)
	      Printf( "Memory: %.2f%% free, Min index:%d Max index:%d Checksum:%X\n",
			      (double)(fp)/(double)tp * 100.0, mn, mx, checksum);
#else
	      Printf( "\rMemory: %.2f%% free, Min index:%d Max index:%d Checksum:%X",
			      (double)(fp)/(double)tp * 100.0, mn, mx, checksum);
#endif
	    };
	    
	    mco_trans_rollback( t );