/*
- *
* xlog.h
*
- * Postgres transaction log manager
+ * PostgreSQL transaction log manager
+ *
+ * Portions Copyright (c) 1996-2003, PostgreSQL Global Development Group
+ * Portions Copyright (c) 1994, Regents of the University of California
*
+ * $PostgreSQL: pgsql/src/include/access/xlog.h,v 1.54 2004/07/21 22:31:25 tgl Exp $
*/
#ifndef XLOG_H
#define XLOG_H
#include "access/rmgr.h"
#include "access/transam.h"
#include "access/xlogdefs.h"
+#include "storage/buf.h"
+#include "utils/pg_crc.h"
+
+/*
+ * Header for each record in XLOG
+ *
+ * NOTE: xl_len counts only the rmgr data, not the XLogRecord header,
+ * and also not any backup blocks appended to the record (which are signaled
+ * by xl_info flag bits). The total space needed for an XLOG record is
+ * really:
+ *
+ * SizeOfXLogRecord + xl_len + n_backup_blocks * (sizeof(BkpBlock) + BLCKSZ)
+ *
+ * rounded up to a MAXALIGN boundary (so that all xlog records start on
+ * MAXALIGN boundaries).
+ */
typedef struct XLogRecord
{
+ crc64 xl_crc; /* CRC for this record */
XLogRecPtr xl_prev; /* ptr to previous record in log */
XLogRecPtr xl_xact_prev; /* ptr to previous record of this xact */
TransactionId xl_xid; /* xact id */
- uint16 xl_len; /* len of record *data* on this page */
- uint8 xl_info;
- RmgrId xl_rmid; /* resource manager inserted this record */
+ uint16 xl_len; /* total len of rmgr data */
+ uint8 xl_info; /* flag bits, see below */
+ RmgrId xl_rmid; /* resource manager for this record */
/* ACTUAL LOG DATA FOLLOWS AT END OF STRUCT */
} XLogRecord;
-#define SizeOfXLogRecord DOUBLEALIGN(sizeof(XLogRecord))
-#define MAXLOGRECSZ (2 * BLCKSZ)
+#define SizeOfXLogRecord MAXALIGN(sizeof(XLogRecord))
+#define MAXLOGRECSZ 65535 /* the most that'll fit in xl_len */
-#define XLogRecGetData(record) \
- ((char*)record + SizeOfXLogRecord)
+#define XLogRecGetData(record) ((char*) (record) + SizeOfXLogRecord)
/*
- * When there is no space on current page we continue on the next
- * page with subrecord.
+ * XLOG uses only low 4 bits of xl_info. High 4 bits may be used by rmgr.
*/
-typedef struct XLogSubRecord
-{
- uint16 xl_len;
- uint8 xl_info;
-
- /* ACTUAL LOG DATA FOLLOWS AT END OF STRUCT */
-
-} XLogSubRecord;
-
-#define SizeOfXLogSubRecord DOUBLEALIGN(sizeof(XLogSubRecord))
+#define XLR_INFO_MASK 0x0F
/*
- * XLOG uses only low 4 bits of xl_info. High 4 bits may be used
- * by rmgr...
+ * If we backed up any disk blocks with the XLOG record, we use flag bits in
+ * xl_info to signal it. We support backup of up to 3 disk blocks per XLOG
+ * record. (Could support 4 if we cared to dedicate all the xl_info bits for
+ * this purpose; currently bit 0 of xl_info is unused and available.)
*/
-#define XLR_TO_BE_CONTINUED 0x01
-#define XLR_INFO_MASK 0x0F
-
-#define XLOG_PAGE_MAGIC 0x17345168
-
-typedef struct XLogPageHeaderData
-{
- uint32 xlp_magic;
- uint16 xlp_info;
-} XLogPageHeaderData;
+#define XLR_BKP_BLOCK_MASK 0x0E /* all info bits used for bkp
+ * blocks */
+#define XLR_MAX_BKP_BLOCKS 3
+#define XLR_SET_BKP_BLOCK(iblk) (0x08 >> (iblk))
+#define XLR_BKP_BLOCK_1 XLR_SET_BKP_BLOCK(0) /* 0x08 */
+#define XLR_BKP_BLOCK_2 XLR_SET_BKP_BLOCK(1) /* 0x04 */
+#define XLR_BKP_BLOCK_3 XLR_SET_BKP_BLOCK(2) /* 0x02 */
-#define SizeOfXLogPHD DOUBLEALIGN(sizeof(XLogPageHeaderData))
-
-typedef XLogPageHeaderData *XLogPageHeader;
-
-#define XLP_FIRST_IS_SUBRECORD 0x0001
-
-#define XLByteLT(left, right) \
- (right.xlogid > left.xlogid || \
- (right.xlogid == left.xlogid && right.xrecoff > left.xrecoff))
-
-#define XLByteLE(left, right) \
- (right.xlogid > left.xlogid || \
- (right.xlogid == left.xlogid && right.xrecoff >= left.xrecoff))
-
-#define XLByteEQ(left, right) \
- (right.xlogid == left.xlogid && right.xrecoff == left.xrecoff)
-
-extern StartUpID ThisStartUpID; /* current SUI */
-extern bool InRecovery;
-extern XLogRecPtr MyLastRecPtr;
+/*
+ * Sometimes we log records which are out of transaction control.
+ * Rmgr may "or" XLOG_NO_TRAN into info passed to XLogInsert to indicate this.
+ */
+#define XLOG_NO_TRAN XLR_INFO_MASK
-typedef struct RmgrData
+/*
+ * List of these structs is used to pass data to XLogInsert().
+ *
+ * If buffer is valid then XLOG will check if buffer must be backed up
+ * (ie, whether this is first change of that page since last checkpoint).
+ * If so, the whole page contents are attached to the XLOG record, and XLOG
+ * sets XLR_BKP_BLOCK_X bit in xl_info. Note that the buffer must be pinned
+ * and locked while this is going on, so that it won't change under us.
+ * NB: when this happens, we do not bother to insert the associated data into
+ * the XLOG record, since we assume it's present in the buffer. Therefore,
+ * rmgr redo routines MUST pay attention to XLR_BKP_BLOCK_X to know what
+ * is actually stored in the XLOG record.
+ */
+typedef struct XLogRecData
{
- char *rm_name;
- void (*rm_redo)(XLogRecPtr lsn, XLogRecord *rptr);
- void (*rm_undo)(XLogRecPtr lsn, XLogRecord *rptr);
- void (*rm_desc)(char *buf, uint8 xl_info, char *rec);
-} RmgrData;
-
-extern RmgrData RmgrTable[];
-
-extern XLogRecPtr XLogInsert(RmgrId rmid, uint8 info,
- char *hdr, uint32 hdrlen,
- char *buf, uint32 buflen);
+ Buffer buffer; /* buffer associated with this data */
+ char *data;
+ uint32 len;
+ struct XLogRecData *next;
+} XLogRecData;
+
+extern TimeLineID ThisTimeLineID; /* current TLI */
+extern bool InRecovery;
+extern XLogRecPtr MyLastRecPtr;
+extern bool MyXactMadeXLogEntry;
+extern bool MyXactMadeTempRelUpdate;
+extern XLogRecPtr ProcLastRecEnd;
+
+/* these variables are GUC parameters related to XLOG */
+extern int CheckPointSegments;
+extern int XLOGbuffers;
+extern char *XLogArchiveCommand;
+extern char *XLOG_sync_method;
+extern const char XLOG_sync_method_default[];
+
+#define XLogArchivingActive() (XLogArchiveCommand[0] != '\0')
+
+#ifdef WAL_DEBUG
+extern bool XLOG_DEBUG;
+#endif
+
+extern XLogRecPtr XLogInsert(RmgrId rmid, uint8 info, XLogRecData *rdata);
extern void XLogFlush(XLogRecPtr RecPtr);
-#endif /* XLOG_H */
+extern void xlog_redo(XLogRecPtr lsn, XLogRecord *record);
+extern void xlog_undo(XLogRecPtr lsn, XLogRecord *record);
+extern void xlog_desc(char *buf, uint8 xl_info, char *rec);
+
+extern void UpdateControlFile(void);
+extern int XLOGShmemSize(void);
+extern void XLOGShmemInit(void);
+extern void XLOGPathInit(void);
+extern void BootStrapXLOG(void);
+extern void StartupXLOG(void);
+extern void ShutdownXLOG(int code, Datum arg);
+extern void InitXLOGAccess(void);
+extern void CreateCheckPoint(bool shutdown, bool force);
+extern void XLogPutNextOid(Oid nextOid);
+extern XLogRecPtr GetRedoRecPtr(void);
+
+/* in storage/ipc/sinval.c, but don't want to declare in sinval.h because
+ * we'd have to include xlog.h into that ...
+ */
+extern XLogRecPtr GetUndoRecPtr(void);
+
+#endif /* XLOG_H */
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