extend.c

eXtremeDB数据库在Linux平台下的使用源码。内含多个示例程序

/***************************************************************
 *                                                             *
 * Copyright (c) 2001-2007 McObject LLC. All Right Reserved.   *
 *                                                             *
 ***************************************************************/

/*
 * This sample demonstarates database extention API -
 * mco_db_extend()
 */
#include "platform.h"
#include <stdio.h>
#include <stdlib.h>
#include "samples.h"

static const char   *   dbname       = "SimpleDb";
static const int        FIRST_SEGSZ  = 1024 * 2000UL;
static const int        SECOND_SEGSZ = 1024 * 6000UL;
#ifndef MCO_PLATFORM_X64
static const int        PAGESIZE = 96;
#else
static const int        PAGESIZE = 192;
#endif

void _SH_(void) {

	char text[] = {
		"\nThis example demonstrates eXtremeDB memory extension API\n"
		"\nCopyright (c) 2001-2007 McObject LLC. All Right Reserved.\n\n"
	};

	printf("%s\nPress Enter to start", text);

}


/* Produces database memory report
 */
void showMem( mco_db_h db ) {
	mco_puint freepg, totalpg;

	mco_db_free_pages( db, & freepg );
	mco_db_total_pages( db, & totalpg );

	printf(	"\n\tMemory Report:\n\ttotal pages=%d (%dK)\n\tfree pages=%d (%dK)\n\tused %dK\n",
		totalpg,
		totalpg * PAGESIZE / 1024,
		freepg,
		freepg * PAGESIZE / 1024,
		(totalpg - freepg) * PAGESIZE / 1024
		);
}


/* fatal error handler */
static void errhandler( int n ) {
	printf( "\neXtremeDB fatal error: %d", n );
	getchar();
	exit( -1 );
}


int main( void ) {
	MCO_RET     rc;
	mco_db_h    db = 0;
	char      	*start_mem1 = 0;
	char      	*start_mem2 = 0;
	mco_runtime_info_t info;

	_SH_();
	mco_get_runtime_info( &info);
	if ( info.mco_shm_supported ) {
		printf("\nDatabase extention API is not available for the shared memory database runtime\n");
		exit (1);
	};

	start_mem1 = malloc( FIRST_SEGSZ );

	/* set fatal error handler */
	mco_error_set_handler( &errhandler );

	mco_runtime_start();
	printf("\nAllocating initial memory pool of %dK for the database at the 0x%x\n",
		FIRST_SEGSZ/1024, start_mem1);
		
	/* Create a database, using first memory segment */
	rc = mco_db_open( dbname, simple_get_dictionary(), start_mem1, FIRST_SEGSZ, (uint2) PAGESIZE );

	if ( rc ) {
		printf( "\nerror creating database %d", rc );
		mco_runtime_stop();
		exit( 1 );
	}

	/* connect to the database, obtain a database handle */
	mco_db_connect( dbname, &db );

	showMem( db );

	/* allocate the second database segment and "extend" the database */
	start_mem2 = ( SECOND_SEGSZ > 0 ) ? malloc( SECOND_SEGSZ ) : 0;

	printf("\nExtending the database memory pool by %dK at the 0x%x\n",
		SECOND_SEGSZ/1024, start_mem2);

	if ( start_mem2 ) mco_db_extend( dbname, start_mem2, SECOND_SEGSZ );

	showMem( db );

	/* disconnect from the database, db is no longer valid */
	mco_db_disconnect( db );

	/* destroys the memory manager */
	mco_db_close( dbname );

	mco_runtime_stop();
	if( start_mem1 ) free(start_mem1);
	if( start_mem2 ) free(start_mem2);

	printf( "\nPress Enter to finish\n" );
	getchar();
  PROG_EXIT(0);
}