gdk_tm.c

来自「这个是内存数据库中的一个管理工具」· C语言 代码 · 共 165 行

#line 36 "/export/scratch0/monet/monet.GNU.64.64.d.14791/MonetDB/src/gdk/gdk_tm.mx"
#include "monetdb_config.h"
#include "gdk.h"
#include "gdk_tm.h"



#line 60 "/export/scratch0/monet/monet.GNU.64.64.d.14791/MonetDB/src/gdk/gdk_tm.mx"
/* in the commit prelude, the delta status in the memory image of all bats is commited */
static int prelude(int cnt, bat* subcommit) {
	int i = 0;
	while(++i < cnt) {
		bat bid = subcommit?subcommit[i]:i;
		if (BBP_status(bid) & BBPPERSISTENT) {
			BAT *b = BBP_cache(bid);

			if (b == NULL && (BBP_status(bid) & BBPSWAPPED)) {
				b = BBPquickdesc(bid, TRUE);
				if (b == NULL) return -1;
			}
			if (b) {
				BATcommit(b);
			}
		}
	}
	return 0;
}

/* in the commit epilogue, the BBP-status of the bats is changed to reflect their presence in the succeeded checkpoint. 
 * Also bats from the previous checkpoint that were deleted now are physically destroyed.
 */
static int epilogue(int cnt, bat* subcommit) {
	int i = 0;
	while(++i < cnt) {
		bat bid = subcommit?subcommit[i]:i;
		if (BBP_status(bid) & BBPPERSISTENT) {
			BBP_status_on(bid, BBPEXISTING, subcommit?"TMsubcommit":"TMcommit");
		} else if ((BBP_status(bid) & (BBPDELETED | BBPTMP)) && BBP_refs(bid) <= 0 && BBP_lrefs(bid) <= 0) {
			BAT *b = BBPquickdesc(bid, TRUE);

			/* the unloaded ones are deleted without loading delete disk images */
			BATdelete(b);	
			if (BBP_cache(bid)) {
				/* those that quickdesc decides to load => free memory */
				BATfree(b);
			}
			BBPclear(bid);	/* clear with locking */
		}
		BBP_status_off(bid, BBPDELETED | BBPSWAPPED | BBPNEW, subcommit?"TMsubcommit":"TMcommit");
	}
	return 0;
}



#line 109 "/export/scratch0/monet/monet.GNU.64.64.d.14791/MonetDB/src/gdk/gdk_tm.mx"
int
TMcommit(void) {
	int ret = -1;

	/* commit with the BBP globally locked */
	BBPlock("TMcommit");
	if (prelude(BBPsize, NULL) == 0 && BBPsync(BBPsize, NULL) == 0) {
		ret = epilogue(BBPsize, NULL);
	}
	BBPunlock("TMcommit");
	return ret;
}



#line 143 "/export/scratch0/monet/monet.GNU.64.64.d.14791/MonetDB/src/gdk/gdk_tm.mx"
int
TMsubcommit(BAT* b) {
	int xx, ret = -1, cnt = 1; /* BBP artifact: slot 0 in the array will be ignored */
	bat *subcommit = (bat*) alloca((BATcount(b)+1)*sizeof(bat));
	BUN p, q;

	/* collect the list and save the new bats outside any locking */
	BATloopFast(b, p, q, xx) {
		bat bid = BBPindex((str) BUNtail(b,p));
		if (bid < 0) bid = -bid;
		if (bid) subcommit[cnt++] = bid;
	}
	/* sort the list on BAT id */ 
	GDKqsort(subcommit+1, NULL, cnt-1, sizeof(bat), TYPE_bat, 0);

	if (prelude(cnt, subcommit) == 0) { /* save the new bats outside the lock */
		/* lock just prevents BBPtrims, and other global (sub-)commits */
		gdk_set_lock(GDKtrimLock, "TMsubcommit");
 		if (BBPsync(cnt, subcommit) == 0) { /* write BBP.dir (++) */
			ret = epilogue(cnt, subcommit);
		}
		gdk_unset_lock(GDKtrimLock, "TMsubcommit");
	}
	return ret;
}



#line 176 "/export/scratch0/monet/monet.GNU.64.64.d.14791/MonetDB/src/gdk/gdk_tm.mx"
int
TMabort(void)
{
	int i;

	BBPlock("TMabort");
	for (i = 1; i < BBPsize; i++) {
		if (BBP_status(i) & BBPNEW) {
			BAT *b = BBPquickdesc(i, FALSE);

			if (b) {
				if (b->batPersistence == PERSISTENT)
					BBPdecref(i, TRUE);
				b->batPersistence = TRANSIENT;
				b->batDirtydesc = 1;
			}
		}
	}
	for (i = 1; i < BBPsize; i++) {
		if (BBP_status(i) & (BBPPERSISTENT | BBPDELETED | BBPSWAPPED)) {
			BAT *b = BBPquickdesc(i, TRUE);

			if (b == NULL)
				continue;

			BBPfix(i);
			if (BATdirty(b) || DELTAdirty(b)) {
				/* BUN move-backes need a real BAT! */
				/* Stefan: 
				 * Actually, in case DELTAdirty(b), i.e., a
				 * BAT with differences that is
				 * saved/swapped-out but not yet committed,
				 * we (AFAIK) don't have to load the BAT and
				 * apply the undo, but rather could simply
				 * discard the delta and revive the backup;
				 * however, I don't know how to do this
				 * (yet), hence we stick with this solution
				 * for the time being --- it should be
				 * correct though it might not be the most
				 * efficient way...
				 */
				b = BBPdescriptor(i);
				BATundo(b);
			}
			if (BBP_status(i) & BBPDELETED) {
				BBP_status_on(i, BBPEXISTING, "TMabort");
				if (b->batPersistence != PERSISTENT)
					BBPincref(i, TRUE);
				b->batPersistence = PERSISTENT;
				b->batDirtydesc = 1;
			}
			BBPunfix(i);
		}
		BBP_status_off(i, BBPDELETED | BBPSWAPPED | BBPNEW, "TMabort");
	}
	BBPunlock("TMabort");
	return 0;
}


#line 235 "/export/scratch0/monet/monet.GNU.64.64.d.14791/MonetDB/src/gdk/gdk_tm.mx"