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24 | 24 | * Portions Copyright (c) 1996-2004, PostgreSQL Global Development Group |
25 | 25 | * Portions Copyright (c) 1994, Regents of the University of California |
26 | 26 | * |
27 | | - * $PostgreSQL: pgsql/src/backend/access/transam/clog.c,v 1.25 2004/08/29 05:06:40 momjian Exp $ |
| 27 | + * $PostgreSQL: pgsql/src/backend/access/transam/clog.c,v 1.26 2004/08/30 19:00:42 tgl Exp $ |
28 | 28 | * |
29 | 29 | *------------------------------------------------------------------------- |
30 | 30 | */ |
@@ -210,10 +210,41 @@ ZeroCLOGPage(int pageno, bool writeXlog) |
210 | 210 | void |
211 | 211 | StartupCLOG(void) |
212 | 212 | { |
| 213 | +TransactionIdxid=ShmemVariableCache->nextXid; |
| 214 | +intpageno=TransactionIdToPage(xid); |
| 215 | +intbyteno=TransactionIdToByte(xid); |
| 216 | +intbshift=TransactionIdToBIndex(xid)*CLOG_BITS_PER_XACT; |
| 217 | +intslotno; |
| 218 | +char*byteptr; |
| 219 | + |
| 220 | +LWLockAcquire(CLogControlLock,LW_EXCLUSIVE); |
| 221 | + |
213 | 222 | /* |
214 | 223 | * Initialize our idea of the latest page number. |
215 | 224 | */ |
216 | | -ClogCtl->shared->latest_page_number=TransactionIdToPage(ShmemVariableCache->nextXid); |
| 225 | +ClogCtl->shared->latest_page_number=pageno; |
| 226 | + |
| 227 | +/* |
| 228 | + * Zero out the remainder of the current clog page. Under normal |
| 229 | + * circumstances it should be zeroes already, but it seems at least |
| 230 | + * theoretically possible that XLOG replay will have settled on a |
| 231 | + * nextXID value that is less than the last XID actually used and |
| 232 | + * marked by the previous database lifecycle (since subtransaction |
| 233 | + * commit writes clog but makes no WAL entry). Let's just be safe. |
| 234 | + * (We need not worry about pages beyond the current one, since those |
| 235 | + * will be zeroed when first used.) |
| 236 | + */ |
| 237 | +slotno=SimpleLruReadPage(ClogCtl,pageno,xid); |
| 238 | +byteptr=ClogCtl->shared->page_buffer[slotno]+byteno; |
| 239 | + |
| 240 | +/* Zero so-far-unused positions in the current byte */ |
| 241 | +*byteptr &= (1 <<bshift)-1; |
| 242 | +/* Zero the rest of the page */ |
| 243 | +MemSet(byteptr+1,0,BLCKSZ-byteno-1); |
| 244 | + |
| 245 | +ClogCtl->shared->page_status[slotno]=SLRU_PAGE_DIRTY; |
| 246 | + |
| 247 | +LWLockRelease(CLogControlLock); |
217 | 248 | } |
218 | 249 |
|
219 | 250 | /* |
|