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Diffstat (limited to 'src/include/access/xlog_internal.h')
| -rw-r--r-- | src/include/access/xlog_internal.h | 336 |
1 files changed, 336 insertions, 0 deletions
diff --git a/src/include/access/xlog_internal.h b/src/include/access/xlog_internal.h new file mode 100644 index 0000000..dcf41e9 --- /dev/null +++ b/src/include/access/xlog_internal.h @@ -0,0 +1,336 @@ +/* + * xlog_internal.h + * + * PostgreSQL write-ahead log internal declarations + * + * NOTE: this file is intended to contain declarations useful for + * manipulating the XLOG files directly, but it is not supposed to be + * needed by rmgr routines (redo support for individual record types). + * So the XLogRecord typedef and associated stuff appear in xlogrecord.h. + * + * Note: This file must be includable in both frontend and backend contexts, + * to allow stand-alone tools like pg_receivewal to deal with WAL files. + * + * Portions Copyright (c) 1996-2021, PostgreSQL Global Development Group + * Portions Copyright (c) 1994, Regents of the University of California + * + * src/include/access/xlog_internal.h + */ +#ifndef XLOG_INTERNAL_H +#define XLOG_INTERNAL_H + +#include "access/xlogdefs.h" +#include "access/xlogreader.h" +#include "datatype/timestamp.h" +#include "lib/stringinfo.h" +#include "pgtime.h" +#include "storage/block.h" +#include "storage/relfilenode.h" + + +/* + * Each page of XLOG file has a header like this: + */ +#define XLOG_PAGE_MAGIC 0xD10D /* can be used as WAL version indicator */ + +typedef struct XLogPageHeaderData +{ + uint16 xlp_magic; /* magic value for correctness checks */ + uint16 xlp_info; /* flag bits, see below */ + TimeLineID xlp_tli; /* TimeLineID of first record on page */ + XLogRecPtr xlp_pageaddr; /* XLOG address of this page */ + + /* + * When there is not enough space on current page for whole record, we + * continue on the next page. xlp_rem_len is the number of bytes + * remaining from a previous page; it tracks xl_tot_len in the initial + * header. Note that the continuation data isn't necessarily aligned. + */ + uint32 xlp_rem_len; /* total len of remaining data for record */ +} XLogPageHeaderData; + +#define SizeOfXLogShortPHD MAXALIGN(sizeof(XLogPageHeaderData)) + +typedef XLogPageHeaderData *XLogPageHeader; + +/* + * When the XLP_LONG_HEADER flag is set, we store additional fields in the + * page header. (This is ordinarily done just in the first page of an + * XLOG file.) The additional fields serve to identify the file accurately. + */ +typedef struct XLogLongPageHeaderData +{ + XLogPageHeaderData std; /* standard header fields */ + uint64 xlp_sysid; /* system identifier from pg_control */ + uint32 xlp_seg_size; /* just as a cross-check */ + uint32 xlp_xlog_blcksz; /* just as a cross-check */ +} XLogLongPageHeaderData; + +#define SizeOfXLogLongPHD MAXALIGN(sizeof(XLogLongPageHeaderData)) + +typedef XLogLongPageHeaderData *XLogLongPageHeader; + +/* When record crosses page boundary, set this flag in new page's header */ +#define XLP_FIRST_IS_CONTRECORD 0x0001 +/* This flag indicates a "long" page header */ +#define XLP_LONG_HEADER 0x0002 +/* This flag indicates backup blocks starting in this page are optional */ +#define XLP_BKP_REMOVABLE 0x0004 +/* Replaces a missing contrecord; see CreateOverwriteContrecordRecord */ +#define XLP_FIRST_IS_OVERWRITE_CONTRECORD 0x0008 +/* All defined flag bits in xlp_info (used for validity checking of header) */ +#define XLP_ALL_FLAGS 0x000F + +#define XLogPageHeaderSize(hdr) \ + (((hdr)->xlp_info & XLP_LONG_HEADER) ? SizeOfXLogLongPHD : SizeOfXLogShortPHD) + +/* wal_segment_size can range from 1MB to 1GB */ +#define WalSegMinSize 1024 * 1024 +#define WalSegMaxSize 1024 * 1024 * 1024 +/* default number of min and max wal segments */ +#define DEFAULT_MIN_WAL_SEGS 5 +#define DEFAULT_MAX_WAL_SEGS 64 + +/* check that the given size is a valid wal_segment_size */ +#define IsPowerOf2(x) (x > 0 && ((x) & ((x)-1)) == 0) +#define IsValidWalSegSize(size) \ + (IsPowerOf2(size) && \ + ((size) >= WalSegMinSize && (size) <= WalSegMaxSize)) + +#define XLogSegmentsPerXLogId(wal_segsz_bytes) \ + (UINT64CONST(0x100000000) / (wal_segsz_bytes)) + +#define XLogSegNoOffsetToRecPtr(segno, offset, wal_segsz_bytes, dest) \ + (dest) = (segno) * (wal_segsz_bytes) + (offset) + +#define XLogSegmentOffset(xlogptr, wal_segsz_bytes) \ + ((xlogptr) & ((wal_segsz_bytes) - 1)) + +/* + * Compute a segment number from an XLogRecPtr. + * + * For XLByteToSeg, do the computation at face value. For XLByteToPrevSeg, + * a boundary byte is taken to be in the previous segment. This is suitable + * for deciding which segment to write given a pointer to a record end, + * for example. + */ +#define XLByteToSeg(xlrp, logSegNo, wal_segsz_bytes) \ + logSegNo = (xlrp) / (wal_segsz_bytes) + +#define XLByteToPrevSeg(xlrp, logSegNo, wal_segsz_bytes) \ + logSegNo = ((xlrp) - 1) / (wal_segsz_bytes) + +/* + * Convert values of GUCs measured in megabytes to equiv. segment count. + * Rounds down. + */ +#define XLogMBVarToSegs(mbvar, wal_segsz_bytes) \ + ((mbvar) / ((wal_segsz_bytes) / (1024 * 1024))) + +/* + * Is an XLogRecPtr within a particular XLOG segment? + * + * For XLByteInSeg, do the computation at face value. For XLByteInPrevSeg, + * a boundary byte is taken to be in the previous segment. + */ +#define XLByteInSeg(xlrp, logSegNo, wal_segsz_bytes) \ + (((xlrp) / (wal_segsz_bytes)) == (logSegNo)) + +#define XLByteInPrevSeg(xlrp, logSegNo, wal_segsz_bytes) \ + ((((xlrp) - 1) / (wal_segsz_bytes)) == (logSegNo)) + +/* Check if an XLogRecPtr value is in a plausible range */ +#define XRecOffIsValid(xlrp) \ + ((xlrp) % XLOG_BLCKSZ >= SizeOfXLogShortPHD) + +/* + * The XLog directory and control file (relative to $PGDATA) + */ +#define XLOGDIR "pg_wal" +#define XLOG_CONTROL_FILE "global/pg_control" + +/* + * These macros encapsulate knowledge about the exact layout of XLog file + * names, timeline history file names, and archive-status file names. + */ +#define MAXFNAMELEN 64 + +/* Length of XLog file name */ +#define XLOG_FNAME_LEN 24 + +/* + * Generate a WAL segment file name. Do not use this macro in a helper + * function allocating the result generated. + */ +#define XLogFileName(fname, tli, logSegNo, wal_segsz_bytes) \ + snprintf(fname, MAXFNAMELEN, "%08X%08X%08X", tli, \ + (uint32) ((logSegNo) / XLogSegmentsPerXLogId(wal_segsz_bytes)), \ + (uint32) ((logSegNo) % XLogSegmentsPerXLogId(wal_segsz_bytes))) + +#define XLogFileNameById(fname, tli, log, seg) \ + snprintf(fname, MAXFNAMELEN, "%08X%08X%08X", tli, log, seg) + +#define IsXLogFileName(fname) \ + (strlen(fname) == XLOG_FNAME_LEN && \ + strspn(fname, "0123456789ABCDEF") == XLOG_FNAME_LEN) + +/* + * XLOG segment with .partial suffix. Used by pg_receivewal and at end of + * archive recovery, when we want to archive a WAL segment but it might not + * be complete yet. + */ +#define IsPartialXLogFileName(fname) \ + (strlen(fname) == XLOG_FNAME_LEN + strlen(".partial") && \ + strspn(fname, "0123456789ABCDEF") == XLOG_FNAME_LEN && \ + strcmp((fname) + XLOG_FNAME_LEN, ".partial") == 0) + +#define XLogFromFileName(fname, tli, logSegNo, wal_segsz_bytes) \ + do { \ + uint32 log; \ + uint32 seg; \ + sscanf(fname, "%08X%08X%08X", tli, &log, &seg); \ + *logSegNo = (uint64) log * XLogSegmentsPerXLogId(wal_segsz_bytes) + seg; \ + } while (0) + +#define XLogFilePath(path, tli, logSegNo, wal_segsz_bytes) \ + snprintf(path, MAXPGPATH, XLOGDIR "/%08X%08X%08X", tli, \ + (uint32) ((logSegNo) / XLogSegmentsPerXLogId(wal_segsz_bytes)), \ + (uint32) ((logSegNo) % XLogSegmentsPerXLogId(wal_segsz_bytes))) + +#define TLHistoryFileName(fname, tli) \ + snprintf(fname, MAXFNAMELEN, "%08X.history", tli) + +#define IsTLHistoryFileName(fname) \ + (strlen(fname) == 8 + strlen(".history") && \ + strspn(fname, "0123456789ABCDEF") == 8 && \ + strcmp((fname) + 8, ".history") == 0) + +#define TLHistoryFilePath(path, tli) \ + snprintf(path, MAXPGPATH, XLOGDIR "/%08X.history", tli) + +#define StatusFilePath(path, xlog, suffix) \ + snprintf(path, MAXPGPATH, XLOGDIR "/archive_status/%s%s", xlog, suffix) + +#define BackupHistoryFileName(fname, tli, logSegNo, startpoint, wal_segsz_bytes) \ + snprintf(fname, MAXFNAMELEN, "%08X%08X%08X.%08X.backup", tli, \ + (uint32) ((logSegNo) / XLogSegmentsPerXLogId(wal_segsz_bytes)), \ + (uint32) ((logSegNo) % XLogSegmentsPerXLogId(wal_segsz_bytes)), \ + (uint32) (XLogSegmentOffset(startpoint, wal_segsz_bytes))) + +#define IsBackupHistoryFileName(fname) \ + (strlen(fname) > XLOG_FNAME_LEN && \ + strspn(fname, "0123456789ABCDEF") == XLOG_FNAME_LEN && \ + strcmp((fname) + strlen(fname) - strlen(".backup"), ".backup") == 0) + +#define BackupHistoryFilePath(path, tli, logSegNo, startpoint, wal_segsz_bytes) \ + snprintf(path, MAXPGPATH, XLOGDIR "/%08X%08X%08X.%08X.backup", tli, \ + (uint32) ((logSegNo) / XLogSegmentsPerXLogId(wal_segsz_bytes)), \ + (uint32) ((logSegNo) % XLogSegmentsPerXLogId(wal_segsz_bytes)), \ + (uint32) (XLogSegmentOffset((startpoint), wal_segsz_bytes))) + +/* + * Information logged when we detect a change in one of the parameters + * important for Hot Standby. + */ +typedef struct xl_parameter_change +{ + int MaxConnections; + int max_worker_processes; + int max_wal_senders; + int max_prepared_xacts; + int max_locks_per_xact; + int wal_level; + bool wal_log_hints; + bool track_commit_timestamp; +} xl_parameter_change; + +/* logs restore point */ +typedef struct xl_restore_point +{ + TimestampTz rp_time; + char rp_name[MAXFNAMELEN]; +} xl_restore_point; + +/* Overwrite of prior contrecord */ +typedef struct xl_overwrite_contrecord +{ + XLogRecPtr overwritten_lsn; + TimestampTz overwrite_time; +} xl_overwrite_contrecord; + +/* End of recovery mark, when we don't do an END_OF_RECOVERY checkpoint */ +typedef struct xl_end_of_recovery +{ + TimestampTz end_time; + TimeLineID ThisTimeLineID; /* new TLI */ + TimeLineID PrevTimeLineID; /* previous TLI we forked off from */ +} xl_end_of_recovery; + +/* + * The functions in xloginsert.c construct a chain of XLogRecData structs + * to represent the final WAL record. + */ +typedef struct XLogRecData +{ + struct XLogRecData *next; /* next struct in chain, or NULL */ + char *data; /* start of rmgr data to include */ + uint32 len; /* length of rmgr data to include */ +} XLogRecData; + +/* + * Recovery target action. + */ +typedef enum +{ + RECOVERY_TARGET_ACTION_PAUSE, + RECOVERY_TARGET_ACTION_PROMOTE, + RECOVERY_TARGET_ACTION_SHUTDOWN +} RecoveryTargetAction; + +/* + * Method table for resource managers. + * + * This struct must be kept in sync with the PG_RMGR definition in + * rmgr.c. + * + * rm_identify must return a name for the record based on xl_info (without + * reference to the rmid). For example, XLOG_BTREE_VACUUM would be named + * "VACUUM". rm_desc can then be called to obtain additional detail for the + * record, if available (e.g. the last block). + * + * rm_mask takes as input a page modified by the resource manager and masks + * out bits that shouldn't be flagged by wal_consistency_checking. + * + * RmgrTable[] is indexed by RmgrId values (see rmgrlist.h). + */ +typedef struct RmgrData +{ + const char *rm_name; + void (*rm_redo) (XLogReaderState *record); + void (*rm_desc) (StringInfo buf, XLogReaderState *record); + const char *(*rm_identify) (uint8 info); + void (*rm_startup) (void); + void (*rm_cleanup) (void); + void (*rm_mask) (char *pagedata, BlockNumber blkno); +} RmgrData; + +extern const RmgrData RmgrTable[]; + +/* + * Exported to support xlog switching from checkpointer + */ +extern pg_time_t GetLastSegSwitchData(XLogRecPtr *lastSwitchLSN); +extern XLogRecPtr RequestXLogSwitch(bool mark_unimportant); + +extern void GetOldestRestartPoint(XLogRecPtr *oldrecptr, TimeLineID *oldtli); + +/* + * Exported for the functions in timeline.c and xlogarchive.c. Only valid + * in the startup process. + */ +extern bool ArchiveRecoveryRequested; +extern bool InArchiveRecovery; +extern bool StandbyMode; +extern char *recoveryRestoreCommand; + +#endif /* XLOG_INTERNAL_H */ |