diff options
Diffstat (limited to 'src/include/access/xlog.h')
| -rw-r--r-- | src/include/access/xlog.h | 171 |
1 files changed, 108 insertions, 63 deletions
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h index c17bf32cc5..dd079496ed 100644 --- a/src/include/access/xlog.h +++ b/src/include/access/xlog.h @@ -3,7 +3,10 @@ * * PostgreSQL transaction log manager * - * $Header: /cvsroot/pgsql/src/include/access/xlog.h,v 1.18 2001/02/26 00:50:07 tgl Exp $ + * Portions Copyright (c) 1996-2001, PostgreSQL Global Development Group + * Portions Copyright (c) 1994, Regents of the University of California + * + * $Id: xlog.h,v 1.19 2001/03/13 01:17:06 tgl Exp $ */ #ifndef XLOG_H #define XLOG_H @@ -11,97 +14,126 @@ #include "access/rmgr.h" #include "access/transam.h" #include "access/xlogdefs.h" -#include "access/xlogutils.h" +#include "utils/pg_crc.h" -typedef struct crc64 -{ - uint32 crc1; - uint32 crc2; -} crc64; +/* + * 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) + */ typedef struct XLogRecord { - crc64 xl_crc; + 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; /* total len of record *data* */ - 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; /* len of data left */ - - /* 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... - * - * We support backup of 2 blocks per record only. - * If we backed up some of these blocks then we use - * flags below to signal rmgr about this on recovery. + * We support backup of up to 2 disk blocks per XLOG record (could support + * more if we cared to dedicate more xl_info bits for this purpose; currently + * do not need more than 2 anyway). If we backed up any disk blocks then we + * use flag bits in xl_info to signal it. */ -#define XLR_SET_BKP_BLOCK(iblk) (0x08 >> iblk) +#define XLR_BKP_BLOCK_MASK 0x0C /* all info bits used for bkp blocks */ +#define XLR_MAX_BKP_BLOCKS 2 +#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_INFO_MASK 0x0F /* * Sometimes we log records which are out of transaction control. - * Rmgr may use flag below for this purpose. + * Rmgr may "or" XLOG_NO_TRAN into info passed to XLogInsert to indicate this. */ #define XLOG_NO_TRAN XLR_INFO_MASK -#define XLOG_PAGE_MAGIC 0x17345168 +/* + * Header info for a backup block appended to an XLOG record. + * + * Note that the backup block has its own CRC, and is not covered by + * the CRC of the XLOG record proper. Also note that we don't attempt + * to align either the BkpBlock struct or the block's data. + */ +typedef struct BkpBlock +{ + crc64 crc; + RelFileNode node; + BlockNumber block; +} BkpBlock; -typedef struct XLogPageHeaderData +/* + * When there is not enough space on current page for whole record, we + * continue on the next page with continuation record. (However, the + * XLogRecord header will never be split across pages; if there's less than + * SizeOfXLogRecord space left at the end of a page, we just waste it.) + * + * Note that xl_rem_len includes backup-block data, unlike xl_len in the + * initial header. + */ +typedef struct XLogContRecord { - uint32 xlp_magic; - uint16 xlp_info; -} XLogPageHeaderData; + uint32 xl_rem_len; /* total len of remaining data for record */ -#define SizeOfXLogPHD DOUBLEALIGN(sizeof(XLogPageHeaderData)) + /* ACTUAL LOG DATA FOLLOWS AT END OF STRUCT */ -typedef XLogPageHeaderData *XLogPageHeader; +} XLogContRecord; -/* When record crosses page boundary */ -#define XLP_FIRST_IS_SUBRECORD 0x0001 +#define SizeOfXLogContRecord MAXALIGN(sizeof(XLogContRecord)) -#define XLByteLT(left, right) \ - (right.xlogid > left.xlogid || \ - (right.xlogid == left.xlogid && right.xrecoff > left.xrecoff)) +/* + * Each page of XLOG file has a header like this: + */ +#define XLOG_PAGE_MAGIC 0x17345169 /* can be used as WAL version indicator */ -#define XLByteLE(left, right) \ - (right.xlogid > left.xlogid || \ - (right.xlogid == left.xlogid && right.xrecoff >= left.xrecoff)) +typedef struct XLogPageHeaderData +{ + uint32 xlp_magic; /* magic value for correctness checks */ + uint16 xlp_info; /* flag bits, see below */ +} XLogPageHeaderData; -#define XLByteEQ(left, right) \ - (right.xlogid == left.xlogid && right.xrecoff == left.xrecoff) +#define SizeOfXLogPHD MAXALIGN(sizeof(XLogPageHeaderData)) -extern StartUpID ThisStartUpID; /* current SUI */ -extern bool InRecovery; -extern XLogRecPtr MyLastRecPtr; +typedef XLogPageHeaderData *XLogPageHeader; + +/* When record crosses page boundary, set this flag in new page's header */ +#define XLP_FIRST_IS_CONTRECORD 0x0001 + +/* + * We break each logical log file (xlogid value) into 16Mb segments. + * One possible segment at the end of each log file is wasted, to ensure + * that we don't have problems representing last-byte-position-plus-1. + */ +#define XLogSegSize ((uint32) (16*1024*1024)) +#define XLogSegsPerFile (((uint32) 0xffffffff) / XLogSegSize) +#define XLogFileSize (XLogSegsPerFile * XLogSegSize) +/* + * Method table for resource managers. + * + * RmgrTable[] is indexed by RmgrId values (see rmgr.h). + */ typedef struct RmgrData { char *rm_name; @@ -112,12 +144,19 @@ typedef struct RmgrData extern RmgrData RmgrTable[]; -/* - * List of these structs is used to pass data to XLOG. - * If buffer is valid then XLOG will check if buffer must - * be backup-ed. For backup-ed buffer data will not be - * inserted into record (and XLOG sets - * XLR_BKP_BLOCK_X bit in xl_info). +/*-------------------- + * 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 { @@ -127,11 +166,13 @@ typedef struct XLogRecData struct XLogRecData *next; } XLogRecData; +extern StartUpID ThisStartUpID; /* current SUI */ +extern bool InRecovery; +extern XLogRecPtr MyLastRecPtr; + extern XLogRecPtr XLogInsert(RmgrId rmid, uint8 info, XLogRecData *rdata); extern void XLogFlush(XLogRecPtr RecPtr); -extern void CreateCheckPoint(bool shutdown); - 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); @@ -145,6 +186,10 @@ extern void StartupXLOG(void); extern void ShutdownXLOG(void); extern void CreateCheckPoint(bool shutdown); extern void SetThisStartUpID(void); +extern void XLogPutNextXid(TransactionId nextXid); +extern void XLogPutNextOid(Oid nextOid); +extern void SetRedoRecPtr(void); +extern void 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 ... |