#include "access/transam.h"
#include "access/xlogrecord.h"
#include "storage/buf.h"

Include dependency graph for xlogreader.h:

This graph shows which files directly or indirectly include this file:

Data Structures
struct	WALOpenSegment

struct	WALSegmentContext

struct	XLogReaderRoutine

struct	DecodedBkpBlock

struct	DecodedXLogRecord

struct	XLogReaderState

struct	WALReadError

Macros
#define	XL_ROUTINE(...) &(XLogReaderRoutine){__VA_ARGS__}

#define	XLogRecGetTotalLen(decoder) ((decoder)->record->header.xl_tot_len)

#define	XLogRecGetPrev(decoder) ((decoder)->record->header.xl_prev)

#define	XLogRecGetInfo(decoder) ((decoder)->record->header.xl_info)

#define	XLogRecGetRmid(decoder) ((decoder)->record->header.xl_rmid)

#define	XLogRecGetXid(decoder) ((decoder)->record->header.xl_xid)

#define	XLogRecGetOrigin(decoder) ((decoder)->record->record_origin)

#define	XLogRecGetTopXid(decoder) ((decoder)->record->toplevel_xid)

#define	XLogRecGetData(decoder) ((decoder)->record->main_data)

#define	XLogRecGetDataLen(decoder) ((decoder)->record->main_data_len)

#define	XLogRecHasAnyBlockRefs(decoder) ((decoder)->record->max_block_id >= 0)

#define	XLogRecMaxBlockId(decoder) ((decoder)->record->max_block_id)

#define	XLogRecGetBlock(decoder, i) (&(decoder)->record->blocks[(i)])

#define	XLogRecHasBlockRef(decoder, block_id)

#define	XLogRecHasBlockImage(decoder, block_id) ((decoder)->record->blocks[block_id].has_image)

#define	XLogRecBlockImageApply(decoder, block_id) ((decoder)->record->blocks[block_id].apply_image)

#define	XLogRecHasBlockData(decoder, block_id) ((decoder)->record->blocks[block_id].has_data)

Typedefs
typedef struct WALOpenSegment	WALOpenSegment

typedef struct WALSegmentContext	WALSegmentContext

typedef struct XLogReaderState	XLogReaderState

typedef int(*	XLogPageReadCB) (XLogReaderState xlogreader, XLogRecPtr targetPagePtr, int reqLen, XLogRecPtr targetRecPtr, char readBuf)

typedef void(*	WALSegmentOpenCB) (XLogReaderState xlogreader, XLogSegNo nextSegNo, TimeLineID tli_p)

typedef void(*	WALSegmentCloseCB) (XLogReaderState *xlogreader)

typedef struct XLogReaderRoutine	XLogReaderRoutine

typedef struct DecodedXLogRecord	DecodedXLogRecord

typedef enum XLogPageReadResult	XLogPageReadResult

typedef struct WALReadError	WALReadError

Enumerations
enum	XLogPageReadResult { XLREAD_SUCCESS = 0 , XLREAD_FAIL = -1 , XLREAD_WOULDBLOCK = -2 }

Functions
static bool	XLogReaderHasQueuedRecordOrError (XLogReaderState *state)

XLogReaderState *	XLogReaderAllocate (int wal_segment_size, const char waldir, XLogReaderRoutine routine, void *private_data)

void	XLogReaderFree (XLogReaderState *state)

void	XLogReaderSetDecodeBuffer (XLogReaderState state, void buffer, size_t size)

void	XLogBeginRead (XLogReaderState *state, XLogRecPtr RecPtr)

XLogRecPtr	XLogFindNextRecord (XLogReaderState *state, XLogRecPtr RecPtr)

struct XLogRecord *	XLogReadRecord (XLogReaderState state, char *errormsg)

DecodedXLogRecord *	XLogNextRecord (XLogReaderState state, char *errormsg)

XLogRecPtr	XLogReleasePreviousRecord (XLogReaderState *state)

DecodedXLogRecord *	XLogReadAhead (XLogReaderState *state, bool nonblocking)

bool	XLogReaderValidatePageHeader (XLogReaderState state, XLogRecPtr recptr, char phdr)

void	XLogReaderResetError (XLogReaderState *state)

bool	WALRead (XLogReaderState state, char buf, XLogRecPtr startptr, Size count, TimeLineID tli, WALReadError *errinfo)

size_t	DecodeXLogRecordRequiredSpace (size_t xl_tot_len)

bool	DecodeXLogRecord (XLogReaderState state, DecodedXLogRecord decoded, XLogRecord record, XLogRecPtr lsn, char *errormsg)

FullTransactionId	XLogRecGetFullXid (XLogReaderState *record)

bool	RestoreBlockImage (XLogReaderState record, uint8 block_id, char page)

char *	XLogRecGetBlockData (XLogReaderState record, uint8 block_id, Size len)

void	XLogRecGetBlockTag (XLogReaderState record, uint8 block_id, RelFileLocator rlocator, ForkNumber forknum, BlockNumber blknum)

bool	XLogRecGetBlockTagExtended (XLogReaderState record, uint8 block_id, RelFileLocator rlocator, ForkNumber forknum, BlockNumber blknum, Buffer *prefetch_buffer)

Macro Definition Documentation

◆ XL_ROUTINE

#define XL_ROUTINE ( ... ) &(XLogReaderRoutine){__VA_ARGS__}

Definition at line 117 of file xlogreader.h.

◆ XLogRecBlockImageApply

#define XLogRecBlockImageApply	(	decoder,
		block_id
	)	((decoder)->record->blocks[block_id].apply_image)

Definition at line 425 of file xlogreader.h.

◆ XLogRecGetBlock

#define XLogRecGetBlock	(	decoder,
		i
	)	(&(decoder)->record->blocks[(i)])

Definition at line 419 of file xlogreader.h.

◆ XLogRecGetData

#define XLogRecGetData ( decoder ) ((decoder)->record->main_data)

Definition at line 415 of file xlogreader.h.

◆ XLogRecGetDataLen

#define XLogRecGetDataLen ( decoder ) ((decoder)->record->main_data_len)

Definition at line 416 of file xlogreader.h.

◆ XLogRecGetInfo

#define XLogRecGetInfo ( decoder ) ((decoder)->record->header.xl_info)

Definition at line 410 of file xlogreader.h.

◆ XLogRecGetOrigin

#define XLogRecGetOrigin ( decoder ) ((decoder)->record->record_origin)

Definition at line 413 of file xlogreader.h.

◆ XLogRecGetPrev

#define XLogRecGetPrev ( decoder ) ((decoder)->record->header.xl_prev)

Definition at line 409 of file xlogreader.h.

◆ XLogRecGetRmid

#define XLogRecGetRmid ( decoder ) ((decoder)->record->header.xl_rmid)

Definition at line 411 of file xlogreader.h.

◆ XLogRecGetTopXid

#define XLogRecGetTopXid ( decoder ) ((decoder)->record->toplevel_xid)

Definition at line 414 of file xlogreader.h.

◆ XLogRecGetTotalLen

#define XLogRecGetTotalLen ( decoder ) ((decoder)->record->header.xl_tot_len)

Definition at line 408 of file xlogreader.h.

◆ XLogRecGetXid

#define XLogRecGetXid ( decoder ) ((decoder)->record->header.xl_xid)

Definition at line 412 of file xlogreader.h.

◆ XLogRecHasAnyBlockRefs

#define XLogRecHasAnyBlockRefs ( decoder ) ((decoder)->record->max_block_id >= 0)

Definition at line 417 of file xlogreader.h.

◆ XLogRecHasBlockData

#define XLogRecHasBlockData	(	decoder,
		block_id
	)	((decoder)->record->blocks[block_id].has_data)

Definition at line 427 of file xlogreader.h.

◆ XLogRecHasBlockImage

#define XLogRecHasBlockImage	(	decoder,
		block_id
	)	((decoder)->record->blocks[block_id].has_image)

Definition at line 423 of file xlogreader.h.

◆ XLogRecHasBlockRef

#define XLogRecHasBlockRef	(	decoder,
		block_id
	)

Value:

(((decoder)->record->max_block_id >= (block_id)) && \

((decoder)->record->blocks[block_id].in_use))

Definition at line 420 of file xlogreader.h.

◆ XLogRecMaxBlockId

#define XLogRecMaxBlockId ( decoder ) ((decoder)->record->max_block_id)

Definition at line 418 of file xlogreader.h.

Typedef Documentation

◆ DecodedXLogRecord

typedef struct DecodedXLogRecord DecodedXLogRecord

◆ WALOpenSegment

typedef struct WALOpenSegment WALOpenSegment

◆ WALReadError

typedef struct WALReadError WALReadError

◆ WALSegmentCloseCB

typedef void(* WALSegmentCloseCB) (XLogReaderState *xlogreader)

Definition at line 70 of file xlogreader.h.

◆ WALSegmentContext

typedef struct WALSegmentContext WALSegmentContext

◆ WALSegmentOpenCB

typedef void(* WALSegmentOpenCB) (XLogReaderState *xlogreader, XLogSegNo nextSegNo, TimeLineID *tli_p)

Definition at line 67 of file xlogreader.h.

◆ XLogPageReadCB

typedef int(* XLogPageReadCB) (XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, int reqLen, XLogRecPtr targetRecPtr, char *readBuf)

Definition at line 62 of file xlogreader.h.

◆ XLogPageReadResult

typedef enum XLogPageReadResult XLogPageReadResult

◆ XLogReaderRoutine

typedef struct XLogReaderRoutine XLogReaderRoutine

◆ XLogReaderState

typedef struct XLogReaderState XLogReaderState

Definition at line 59 of file xlogreader.h.

Enumeration Type Documentation

◆ XLogPageReadResult

enum XLogPageReadResult

Enumerator
XLREAD_SUCCESS
XLREAD_FAIL
XLREAD_WOULDBLOCK

Definition at line 349 of file xlogreader.h.

{
    XLREAD_SUCCESS = 0,         /* record is successfully read */
    XLREAD_FAIL = -1,           /* failed during reading a record */
    XLREAD_WOULDBLOCK = -2,     /* nonblocking mode only, no data */
} XLogPageReadResult;

Function Documentation

◆ DecodeXLogRecord()

bool DecodeXLogRecord	(	XLogReaderState *	state,
		DecodedXLogRecord *	decoded,
		XLogRecord *	record,
		XLogRecPtr	lsn,
		char **	errormsg
	)

Definition at line 1672 of file xlogreader.c.

{
    /*
     * read next _size bytes from record buffer, but check for overrun first.
     */
#define COPY_HEADER_FIELD(_dst, _size)          \
    do {                                        \
        if (remaining < _size)                  \
            goto shortdata_err;                 \
        memcpy(_dst, ptr, _size);               \
        ptr += _size;                           \
        remaining -= _size;                     \
    } while(0)
 
    char       *ptr;
    char       *out;
    uint32      remaining;
    uint32      datatotal;
    RelFileLocator *rlocator = NULL;
    uint8       block_id;
 
    decoded->header = *record;
    decoded->lsn = lsn;
    decoded->next = NULL;
    decoded->record_origin = InvalidRepOriginId;
    decoded->toplevel_xid = InvalidTransactionId;
    decoded->main_data = NULL;
    decoded->main_data_len = 0;
    decoded->max_block_id = -1;
    ptr = (char *) record;
    ptr += SizeOfXLogRecord;
    remaining = record->xl_tot_len - SizeOfXLogRecord;
 
    /* Decode the headers */
    datatotal = 0;
    while (remaining > datatotal)
    {
        COPY_HEADER_FIELD(&block_id, sizeof(uint8));
 
        if (block_id == XLR_BLOCK_ID_DATA_SHORT)
        {
            /* XLogRecordDataHeaderShort */
            uint8       main_data_len;
 
            COPY_HEADER_FIELD(&main_data_len, sizeof(uint8));
 
            decoded->main_data_len = main_data_len;
            datatotal += main_data_len;
            break;              /* by convention, the main data fragment is
                                 * always last */
        }
        else if (block_id == XLR_BLOCK_ID_DATA_LONG)
        {
            /* XLogRecordDataHeaderLong */
            uint32      main_data_len;
 
            COPY_HEADER_FIELD(&main_data_len, sizeof(uint32));
            decoded->main_data_len = main_data_len;
            datatotal += main_data_len;
            break;              /* by convention, the main data fragment is
                                 * always last */
        }
        else if (block_id == XLR_BLOCK_ID_ORIGIN)
        {
            COPY_HEADER_FIELD(&decoded->record_origin, sizeof(RepOriginId));
        }
        else if (block_id == XLR_BLOCK_ID_TOPLEVEL_XID)
        {
            COPY_HEADER_FIELD(&decoded->toplevel_xid, sizeof(TransactionId));
        }
        else if (block_id <= XLR_MAX_BLOCK_ID)
        {
            /* XLogRecordBlockHeader */
            DecodedBkpBlock *blk;
            uint8       fork_flags;
 
            /* mark any intervening block IDs as not in use */
            for (int i = decoded->max_block_id + 1; i < block_id; ++i)
                decoded->blocks[i].in_use = false;
 
            if (block_id <= decoded->max_block_id)
            {
                report_invalid_record(state,
                                      "out-of-order block_id %u at %X/%X",
                                      block_id,
                                      LSN_FORMAT_ARGS(state->ReadRecPtr));
                goto err;
            }
            decoded->max_block_id = block_id;
 
            blk = &decoded->blocks[block_id];
            blk->in_use = true;
            blk->apply_image = false;
 
            COPY_HEADER_FIELD(&fork_flags, sizeof(uint8));
            blk->forknum = fork_flags & BKPBLOCK_FORK_MASK;
            blk->flags = fork_flags;
            blk->has_image = ((fork_flags & BKPBLOCK_HAS_IMAGE) != 0);
            blk->has_data = ((fork_flags & BKPBLOCK_HAS_DATA) != 0);
 
            blk->prefetch_buffer = InvalidBuffer;
 
            COPY_HEADER_FIELD(&blk->data_len, sizeof(uint16));
            /* cross-check that the HAS_DATA flag is set iff data_length > 0 */
            if (blk->has_data && blk->data_len == 0)
            {
                report_invalid_record(state,
                                      "BKPBLOCK_HAS_DATA set, but no data included at %X/%X",
                                      LSN_FORMAT_ARGS(state->ReadRecPtr));
                goto err;
            }
            if (!blk->has_data && blk->data_len != 0)
            {
                report_invalid_record(state,
                                      "BKPBLOCK_HAS_DATA not set, but data length is %u at %X/%X",
                                      (unsigned int) blk->data_len,
                                      LSN_FORMAT_ARGS(state->ReadRecPtr));
                goto err;
            }
            datatotal += blk->data_len;
 
            if (blk->has_image)
            {
                COPY_HEADER_FIELD(&blk->bimg_len, sizeof(uint16));
                COPY_HEADER_FIELD(&blk->hole_offset, sizeof(uint16));
                COPY_HEADER_FIELD(&blk->bimg_info, sizeof(uint8));
 
                blk->apply_image = ((blk->bimg_info & BKPIMAGE_APPLY) != 0);
 
                if (BKPIMAGE_COMPRESSED(blk->bimg_info))
                {
                    if (blk->bimg_info & BKPIMAGE_HAS_HOLE)
                        COPY_HEADER_FIELD(&blk->hole_length, sizeof(uint16));
                    else
                        blk->hole_length = 0;
                }
                else
                    blk->hole_length = BLCKSZ - blk->bimg_len;
                datatotal += blk->bimg_len;
 
                /*
                 * cross-check that hole_offset > 0, hole_length > 0 and
                 * bimg_len < BLCKSZ if the HAS_HOLE flag is set.
                 */
                if ((blk->bimg_info & BKPIMAGE_HAS_HOLE) &&
                    (blk->hole_offset == 0 ||
                     blk->hole_length == 0 ||
                     blk->bimg_len == BLCKSZ))
                {
                    report_invalid_record(state,
                                          "BKPIMAGE_HAS_HOLE set, but hole offset %u length %u block image length %u at %X/%X",
                                          (unsigned int) blk->hole_offset,
                                          (unsigned int) blk->hole_length,
                                          (unsigned int) blk->bimg_len,
                                          LSN_FORMAT_ARGS(state->ReadRecPtr));
                    goto err;
                }
 
                /*
                 * cross-check that hole_offset == 0 and hole_length == 0 if
                 * the HAS_HOLE flag is not set.
                 */
                if (!(blk->bimg_info & BKPIMAGE_HAS_HOLE) &&
                    (blk->hole_offset != 0 || blk->hole_length != 0))
                {
                    report_invalid_record(state,
                                          "BKPIMAGE_HAS_HOLE not set, but hole offset %u length %u at %X/%X",
                                          (unsigned int) blk->hole_offset,
                                          (unsigned int) blk->hole_length,
                                          LSN_FORMAT_ARGS(state->ReadRecPtr));
                    goto err;
                }
 
                /*
                 * Cross-check that bimg_len < BLCKSZ if it is compressed.
                 */
                if (BKPIMAGE_COMPRESSED(blk->bimg_info) &&
                    blk->bimg_len == BLCKSZ)
                {
                    report_invalid_record(state,
                                          "BKPIMAGE_COMPRESSED set, but block image length %u at %X/%X",
                                          (unsigned int) blk->bimg_len,
                                          LSN_FORMAT_ARGS(state->ReadRecPtr));
                    goto err;
                }
 
                /*
                 * cross-check that bimg_len = BLCKSZ if neither HAS_HOLE is
                 * set nor COMPRESSED().
                 */
                if (!(blk->bimg_info & BKPIMAGE_HAS_HOLE) &&
                    !BKPIMAGE_COMPRESSED(blk->bimg_info) &&
                    blk->bimg_len != BLCKSZ)
                {
                    report_invalid_record(state,
                                          "neither BKPIMAGE_HAS_HOLE nor BKPIMAGE_COMPRESSED set, but block image length is %u at %X/%X",
                                          (unsigned int) blk->data_len,
                                          LSN_FORMAT_ARGS(state->ReadRecPtr));
                    goto err;
                }
            }
            if (!(fork_flags & BKPBLOCK_SAME_REL))
            {
                COPY_HEADER_FIELD(&blk->rlocator, sizeof(RelFileLocator));
                rlocator = &blk->rlocator;
            }
            else
            {
                if (rlocator == NULL)
                {
                    report_invalid_record(state,
                                          "BKPBLOCK_SAME_REL set but no previous rel at %X/%X",
                                          LSN_FORMAT_ARGS(state->ReadRecPtr));
                    goto err;
                }
 
                blk->rlocator = *rlocator;
            }
            COPY_HEADER_FIELD(&blk->blkno, sizeof(BlockNumber));
        }
        else
        {
            report_invalid_record(state,
                                  "invalid block_id %u at %X/%X",
                                  block_id, LSN_FORMAT_ARGS(state->ReadRecPtr));
            goto err;
        }
    }
 
    if (remaining != datatotal)
        goto shortdata_err;
 
    /*
     * Ok, we've parsed the fragment headers, and verified that the total
     * length of the payload in the fragments is equal to the amount of data
     * left.  Copy the data of each fragment to contiguous space after the
     * blocks array, inserting alignment padding before the data fragments so
     * they can be cast to struct pointers by REDO routines.
     */
    out = ((char *) decoded) +
        offsetof(DecodedXLogRecord, blocks) +
        sizeof(decoded->blocks[0]) * (decoded->max_block_id + 1);
 
    /* block data first */
    for (block_id = 0; block_id <= decoded->max_block_id; block_id++)
    {
        DecodedBkpBlock *blk = &decoded->blocks[block_id];
 
        if (!blk->in_use)
            continue;
 
        Assert(blk->has_image || !blk->apply_image);
 
        if (blk->has_image)
        {
            /* no need to align image */
            blk->bkp_image = out;
            memcpy(out, ptr, blk->bimg_len);
            ptr += blk->bimg_len;
            out += blk->bimg_len;
        }
        if (blk->has_data)
        {
            out = (char *) MAXALIGN(out);
            blk->data = out;
            memcpy(blk->data, ptr, blk->data_len);
            ptr += blk->data_len;
            out += blk->data_len;
        }
    }
 
    /* and finally, the main data */
    if (decoded->main_data_len > 0)
    {
        out = (char *) MAXALIGN(out);
        decoded->main_data = out;
        memcpy(decoded->main_data, ptr, decoded->main_data_len);
        ptr += decoded->main_data_len;
        out += decoded->main_data_len;
    }
 
    /* Report the actual size we used. */
    decoded->size = MAXALIGN(out - (char *) decoded);
    Assert(DecodeXLogRecordRequiredSpace(record->xl_tot_len) >=
           decoded->size);
 
    return true;
 
shortdata_err:
    report_invalid_record(state,
                          "record with invalid length at %X/%X",
                          LSN_FORMAT_ARGS(state->ReadRecPtr));
err:
    *errormsg = state->errormsg_buf;
 
    return false;
}

Referenced by XLogDecodeNextRecord(), and XLogInsertRecord().

◆ DecodeXLogRecordRequiredSpace()

size_t DecodeXLogRecordRequiredSpace ( size_t xl_tot_len )

Definition at line 1639 of file xlogreader.c.

{
    size_t      size = 0;
 
    /* Account for the fixed size part of the decoded record struct. */
    size += offsetof(DecodedXLogRecord, blocks[0]);
    /* Account for the flexible blocks array of maximum possible size. */
    size += sizeof(DecodedBkpBlock) * (XLR_MAX_BLOCK_ID + 1);
    /* Account for all the raw main and block data. */
    size += xl_tot_len;
    /* We might insert padding before main_data. */
    size += (MAXIMUM_ALIGNOF - 1);
    /* We might insert padding before each block's data. */
    size += (MAXIMUM_ALIGNOF - 1) * (XLR_MAX_BLOCK_ID + 1);
    /* We might insert padding at the end. */
    size += (MAXIMUM_ALIGNOF - 1);
 
    return size;
}

References XLR_MAX_BLOCK_ID.

Referenced by DecodeXLogRecord(), InitXLogInsert(), XLogInsertRecord(), and XLogReadRecordAlloc().

◆ RestoreBlockImage()

bool RestoreBlockImage	(	XLogReaderState *	record,
		uint8	block_id,
		char *	page
	)

Definition at line 2066 of file xlogreader.c.

{
    DecodedBkpBlock *bkpb;
    char       *ptr;
    PGAlignedBlock tmp;
 
    if (block_id > record->record->max_block_id ||
        !record->record->blocks[block_id].in_use)
    {
        report_invalid_record(record,
                              "could not restore image at %X/%X with invalid block %d specified",
                              LSN_FORMAT_ARGS(record->ReadRecPtr),
                              block_id);
        return false;
    }
    if (!record->record->blocks[block_id].has_image)
    {
        report_invalid_record(record, "could not restore image at %X/%X with invalid state, block %d",
                              LSN_FORMAT_ARGS(record->ReadRecPtr),
                              block_id);
        return false;
    }
 
    bkpb = &record->record->blocks[block_id];
    ptr = bkpb->bkp_image;
 
    if (BKPIMAGE_COMPRESSED(bkpb->bimg_info))
    {
        /* If a backup block image is compressed, decompress it */
        bool        decomp_success = true;
 
        if ((bkpb->bimg_info & BKPIMAGE_COMPRESS_PGLZ) != 0)
        {
            if (pglz_decompress(ptr, bkpb->bimg_len, tmp.data,
                                BLCKSZ - bkpb->hole_length, true) < 0)
                decomp_success = false;
        }
        else if ((bkpb->bimg_info & BKPIMAGE_COMPRESS_LZ4) != 0)
        {
#ifdef USE_LZ4
            if (LZ4_decompress_safe(ptr, tmp.data,
                                    bkpb->bimg_len, BLCKSZ - bkpb->hole_length) <= 0)
                decomp_success = false;
#else
            report_invalid_record(record, "could not restore image at %X/%X compressed with %s not supported by build, block %d",
                                  LSN_FORMAT_ARGS(record->ReadRecPtr),
                                  "LZ4",
                                  block_id);
            return false;
#endif
        }
        else if ((bkpb->bimg_info & BKPIMAGE_COMPRESS_ZSTD) != 0)
        {
#ifdef USE_ZSTD
            size_t      decomp_result = ZSTD_decompress(tmp.data,
                                                        BLCKSZ - bkpb->hole_length,
                                                        ptr, bkpb->bimg_len);
 
            if (ZSTD_isError(decomp_result))
                decomp_success = false;
#else
            report_invalid_record(record, "could not restore image at %X/%X compressed with %s not supported by build, block %d",
                                  LSN_FORMAT_ARGS(record->ReadRecPtr),
                                  "zstd",
                                  block_id);
            return false;
#endif
        }
        else
        {
            report_invalid_record(record, "could not restore image at %X/%X compressed with unknown method, block %d",
                                  LSN_FORMAT_ARGS(record->ReadRecPtr),
                                  block_id);
            return false;
        }
 
        if (!decomp_success)
        {
            report_invalid_record(record, "could not decompress image at %X/%X, block %d",
                                  LSN_FORMAT_ARGS(record->ReadRecPtr),
                                  block_id);
            return false;
        }
 
        ptr = tmp.data;
    }
 
    /* generate page, taking into account hole if necessary */
    if (bkpb->hole_length == 0)
    {
        memcpy(page, ptr, BLCKSZ);
    }
    else
    {
        memcpy(page, ptr, bkpb->hole_offset);
        /* must zero-fill the hole */
        MemSet(page + bkpb->hole_offset, 0, bkpb->hole_length);
        memcpy(page + (bkpb->hole_offset + bkpb->hole_length),
               ptr + bkpb->hole_offset,
               BLCKSZ - (bkpb->hole_offset + bkpb->hole_length));
    }
 
    return true;
}

References DecodedBkpBlock::bimg_info, DecodedBkpBlock::bimg_len, DecodedBkpBlock::bkp_image, BKPIMAGE_COMPRESS_LZ4, BKPIMAGE_COMPRESS_PGLZ, BKPIMAGE_COMPRESS_ZSTD, BKPIMAGE_COMPRESSED, DecodedXLogRecord::blocks, PGAlignedBlock::data, DecodedBkpBlock::has_image, DecodedBkpBlock::hole_length, DecodedBkpBlock::hole_offset, DecodedBkpBlock::in_use, LSN_FORMAT_ARGS, DecodedXLogRecord::max_block_id, MemSet, pglz_decompress(), XLogReaderState::ReadRecPtr, XLogReaderState::record, and report_invalid_record().

Referenced by GetWALBlockInfo(), verifyBackupPageConsistency(), XLogReadBufferForRedoExtended(), and XLogRecordSaveFPWs().

◆ WALRead()

bool WALRead	(	XLogReaderState *	state,
		char *	buf,
		XLogRecPtr	startptr,
		Size	count,
		TimeLineID	tli,
		WALReadError *	errinfo
	)

Definition at line 1504 of file xlogreader.c.

{
    char       *p;
    XLogRecPtr  recptr;
    Size        nbytes;
#ifndef FRONTEND
    instr_time  io_start;
#endif
 
    p = buf;
    recptr = startptr;
    nbytes = count;
 
    while (nbytes > 0)
    {
        uint32      startoff;
        int         segbytes;
        int         readbytes;
 
        startoff = XLogSegmentOffset(recptr, state->segcxt.ws_segsize);
 
        /*
         * If the data we want is not in a segment we have open, close what we
         * have (if anything) and open the next one, using the caller's
         * provided segment_open callback.
         */
        if (state->seg.ws_file < 0 ||
            !XLByteInSeg(recptr, state->seg.ws_segno, state->segcxt.ws_segsize) ||
            tli != state->seg.ws_tli)
        {
            XLogSegNo   nextSegNo;
 
            if (state->seg.ws_file >= 0)
                state->routine.segment_close(state);
 
            XLByteToSeg(recptr, nextSegNo, state->segcxt.ws_segsize);
            state->routine.segment_open(state, nextSegNo, &tli);
 
            /* This shouldn't happen -- indicates a bug in segment_open */
            Assert(state->seg.ws_file >= 0);
 
            /* Update the current segment info. */
            state->seg.ws_tli = tli;
            state->seg.ws_segno = nextSegNo;
        }
 
        /* How many bytes are within this segment? */
        if (nbytes > (state->segcxt.ws_segsize - startoff))
            segbytes = state->segcxt.ws_segsize - startoff;
        else
            segbytes = nbytes;
 
#ifndef FRONTEND
        /* Measure I/O timing when reading segment */
        io_start = pgstat_prepare_io_time(track_wal_io_timing);
 
        pgstat_report_wait_start(WAIT_EVENT_WAL_READ);
#endif
 
        /* Reset errno first; eases reporting non-errno-affecting errors */
        errno = 0;
        readbytes = pg_pread(state->seg.ws_file, p, segbytes, (off_t) startoff);
 
#ifndef FRONTEND
        pgstat_report_wait_end();
 
        pgstat_count_io_op_time(IOOBJECT_WAL, IOCONTEXT_NORMAL, IOOP_READ,
                                io_start, 1, readbytes);
#endif
 
        if (readbytes <= 0)
        {
            errinfo->wre_errno = errno;
            errinfo->wre_req = segbytes;
            errinfo->wre_read = readbytes;
            errinfo->wre_off = startoff;
            errinfo->wre_seg = state->seg;
            return false;
        }
 
        /* Update state for read */
        recptr += readbytes;
        nbytes -= readbytes;
        p += readbytes;
    }
 
    return true;
}

References Assert(), buf, IOCONTEXT_NORMAL, IOOBJECT_WAL, IOOP_READ, pg_pread, pgstat_count_io_op_time(), pgstat_prepare_io_time(), pgstat_report_wait_end(), pgstat_report_wait_start(), track_wal_io_timing, WALReadError::wre_errno, WALReadError::wre_off, WALReadError::wre_read, WALReadError::wre_req, WALReadError::wre_seg, XLByteInSeg, XLByteToSeg, and XLogSegmentOffset.

Referenced by logical_read_xlog_page(), read_local_xlog_page_guts(), summarizer_read_local_xlog_page(), WALDumpReadPage(), and XLogSendPhysical().

◆ XLogBeginRead()

void XLogBeginRead	(	XLogReaderState *	state,
		XLogRecPtr	RecPtr
	)

Definition at line 232 of file xlogreader.c.

{
    Assert(!XLogRecPtrIsInvalid(RecPtr));
 
    ResetDecoder(state);
 
    /* Begin at the passed-in record pointer. */
    state->EndRecPtr = RecPtr;
    state->NextRecPtr = RecPtr;
    state->ReadRecPtr = InvalidXLogRecPtr;
    state->DecodeRecPtr = InvalidXLogRecPtr;
}

References Assert(), InvalidXLogRecPtr, ResetDecoder(), and XLogRecPtrIsInvalid.

Referenced by DecodingContextFindStartpoint(), extractPageMap(), findLastCheckpoint(), LogicalReplicationSlotHasPendingWal(), LogicalSlotAdvanceAndCheckSnapState(), pg_logical_slot_get_changes_guts(), readOneRecord(), StartLogicalReplication(), SummarizeWAL(), XLogFindNextRecord(), XLogPrefetcherBeginRead(), and XlogReadTwoPhaseData().

◆ XLogFindNextRecord()

XLogRecPtr XLogFindNextRecord	(	XLogReaderState *	state,
		XLogRecPtr	RecPtr
	)

Definition at line 1384 of file xlogreader.c.

{
    XLogRecPtr  tmpRecPtr;
    XLogRecPtr  found = InvalidXLogRecPtr;
    XLogPageHeader header;
    char       *errormsg;
 
    Assert(!XLogRecPtrIsInvalid(RecPtr));
 
    /* Make sure ReadPageInternal() can't return XLREAD_WOULDBLOCK. */
    state->nonblocking = false;
 
    /*
     * skip over potential continuation data, keeping in mind that it may span
     * multiple pages
     */
    tmpRecPtr = RecPtr;
    while (true)
    {
        XLogRecPtr  targetPagePtr;
        int         targetRecOff;
        uint32      pageHeaderSize;
        int         readLen;
 
        /*
         * Compute targetRecOff. It should typically be equal or greater than
         * short page-header since a valid record can't start anywhere before
         * that, except when caller has explicitly specified the offset that
         * falls somewhere there or when we are skipping multi-page
         * continuation record. It doesn't matter though because
         * ReadPageInternal() is prepared to handle that and will read at
         * least short page-header worth of data
         */
        targetRecOff = tmpRecPtr % XLOG_BLCKSZ;
 
        /* scroll back to page boundary */
        targetPagePtr = tmpRecPtr - targetRecOff;
 
        /* Read the page containing the record */
        readLen = ReadPageInternal(state, targetPagePtr, targetRecOff);
        if (readLen < 0)
            goto err;
 
        header = (XLogPageHeader) state->readBuf;
 
        pageHeaderSize = XLogPageHeaderSize(header);
 
        /* make sure we have enough data for the page header */
        readLen = ReadPageInternal(state, targetPagePtr, pageHeaderSize);
        if (readLen < 0)
            goto err;
 
        /* skip over potential continuation data */
        if (header->xlp_info & XLP_FIRST_IS_CONTRECORD)
        {
            /*
             * If the length of the remaining continuation data is more than
             * what can fit in this page, the continuation record crosses over
             * this page. Read the next page and try again. xlp_rem_len in the
             * next page header will contain the remaining length of the
             * continuation data
             *
             * Note that record headers are MAXALIGN'ed
             */
            if (MAXALIGN(header->xlp_rem_len) >= (XLOG_BLCKSZ - pageHeaderSize))
                tmpRecPtr = targetPagePtr + XLOG_BLCKSZ;
            else
            {
                /*
                 * The previous continuation record ends in this page. Set
                 * tmpRecPtr to point to the first valid record
                 */
                tmpRecPtr = targetPagePtr + pageHeaderSize
                    + MAXALIGN(header->xlp_rem_len);
                break;
            }
        }
        else
        {
            tmpRecPtr = targetPagePtr + pageHeaderSize;
            break;
        }
    }
 
    /*
     * we know now that tmpRecPtr is an address pointing to a valid XLogRecord
     * because either we're at the first record after the beginning of a page
     * or we just jumped over the remaining data of a continuation.
     */
    XLogBeginRead(state, tmpRecPtr);
    while (XLogReadRecord(state, &errormsg) != NULL)
    {
        /* past the record we've found, break out */
        if (RecPtr <= state->ReadRecPtr)
        {
            /* Rewind the reader to the beginning of the last record. */
            found = state->ReadRecPtr;
            XLogBeginRead(state, found);
            return found;
        }
    }
 
err:
    XLogReaderInvalReadState(state);
 
    return InvalidXLogRecPtr;
}

References Assert(), err(), InvalidXLogRecPtr, MAXALIGN, readLen, ReadPageInternal(), XLogBeginRead(), XLogPageHeaderSize, XLogReaderInvalReadState(), XLogReadRecord(), XLogRecPtrIsInvalid, XLP_FIRST_IS_CONTRECORD, XLogPageHeaderData::xlp_info, and XLogPageHeaderData::xlp_rem_len.

Referenced by InitXLogReaderState(), main(), and SummarizeWAL().

◆ XLogNextRecord()

DecodedXLogRecord * XLogNextRecord	(	XLogReaderState *	state,
		char **	errormsg
	)

Definition at line 326 of file xlogreader.c.

{
    /* Release the last record returned by XLogNextRecord(). */
    XLogReleasePreviousRecord(state);
 
    if (state->decode_queue_head == NULL)
    {
        *errormsg = NULL;
        if (state->errormsg_deferred)
        {
            if (state->errormsg_buf[0] != '\0')
                *errormsg = state->errormsg_buf;
            state->errormsg_deferred = false;
        }
 
        /*
         * state->EndRecPtr is expected to have been set by the last call to
         * XLogBeginRead() or XLogNextRecord(), and is the location of the
         * error.
         */
        Assert(!XLogRecPtrIsInvalid(state->EndRecPtr));
 
        return NULL;
    }
 
    /*
     * Record this as the most recent record returned, so that we'll release
     * it next time.  This also exposes it to the traditional
     * XLogRecXXX(xlogreader) macros, which work with the decoder rather than
     * the record for historical reasons.
     */
    state->record = state->decode_queue_head;
 
    /*
     * Update the pointers to the beginning and one-past-the-end of this
     * record, again for the benefit of historical code that expected the
     * decoder to track this rather than accessing these fields of the record
     * itself.
     */
    state->ReadRecPtr = state->record->lsn;
    state->EndRecPtr = state->record->next_lsn;
 
    *errormsg = NULL;
 
    return state->record;
}

References Assert(), XLogRecPtrIsInvalid, and XLogReleasePreviousRecord().

Referenced by XLogPrefetcherReadRecord(), and XLogReadRecord().

◆ XLogReadAhead()

DecodedXLogRecord * XLogReadAhead	(	XLogReaderState *	state,
		bool	nonblocking
	)

Definition at line 967 of file xlogreader.c.

{
    XLogPageReadResult result;
 
    if (state->errormsg_deferred)
        return NULL;
 
    result = XLogDecodeNextRecord(state, nonblocking);
    if (result == XLREAD_SUCCESS)
    {
        Assert(state->decode_queue_tail != NULL);
        return state->decode_queue_tail;
    }
 
    return NULL;
}

References Assert(), XLogDecodeNextRecord(), and XLREAD_SUCCESS.

Referenced by XLogPrefetcherNextBlock(), and XLogReadRecord().

◆ XLogReaderAllocate()

XLogReaderState * XLogReaderAllocate	(	int	wal_segment_size,
		const char *	waldir,
		XLogReaderRoutine *	routine,
		void *	private_data
	)

Definition at line 107 of file xlogreader.c.

{
    XLogReaderState *state;
 
    state = (XLogReaderState *)
        palloc_extended(sizeof(XLogReaderState),
                        MCXT_ALLOC_NO_OOM | MCXT_ALLOC_ZERO);
    if (!state)
        return NULL;
 
    /* initialize caller-provided support functions */
    state->routine = *routine;
 
    /*
     * Permanently allocate readBuf.  We do it this way, rather than just
     * making a static array, for two reasons: (1) no need to waste the
     * storage in most instantiations of the backend; (2) a static char array
     * isn't guaranteed to have any particular alignment, whereas
     * palloc_extended() will provide MAXALIGN'd storage.
     */
    state->readBuf = (char *) palloc_extended(XLOG_BLCKSZ,
                                              MCXT_ALLOC_NO_OOM);
    if (!state->readBuf)
    {
        pfree(state);
        return NULL;
    }
 
    /* Initialize segment info. */
    WALOpenSegmentInit(&state->seg, &state->segcxt, wal_segment_size,
                       waldir);
 
    /* system_identifier initialized to zeroes above */
    state->private_data = private_data;
    /* ReadRecPtr, EndRecPtr and readLen initialized to zeroes above */
    state->errormsg_buf = palloc_extended(MAX_ERRORMSG_LEN + 1,
                                          MCXT_ALLOC_NO_OOM);
    if (!state->errormsg_buf)
    {
        pfree(state->readBuf);
        pfree(state);
        return NULL;
    }
    state->errormsg_buf[0] = '\0';
 
    /*
     * Allocate an initial readRecordBuf of minimal size, which can later be
     * enlarged if necessary.
     */
    allocate_recordbuf(state, 0);
    return state;
}

References allocate_recordbuf(), MAX_ERRORMSG_LEN, MCXT_ALLOC_NO_OOM, MCXT_ALLOC_ZERO, palloc_extended(), pfree(), wal_segment_size, and WALOpenSegmentInit().

Referenced by extractPageMap(), findLastCheckpoint(), InitWalRecovery(), InitXLogReaderState(), main(), readOneRecord(), StartReplication(), StartupDecodingContext(), SummarizeWAL(), XLogInsertRecord(), and XlogReadTwoPhaseData().

◆ XLogReaderFree()

void XLogReaderFree ( XLogReaderState * state )

Definition at line 162 of file xlogreader.c.

{
    if (state->seg.ws_file != -1)
        state->routine.segment_close(state);
 
    if (state->decode_buffer && state->free_decode_buffer)
        pfree(state->decode_buffer);
 
    pfree(state->errormsg_buf);
    if (state->readRecordBuf)
        pfree(state->readRecordBuf);
    pfree(state->readBuf);
    pfree(state);
}

References pfree().

Referenced by extractPageMap(), findLastCheckpoint(), FreeDecodingContext(), GetWALRecordsInfo(), main(), pg_get_wal_block_info(), pg_get_wal_record_info(), readOneRecord(), ShutdownWalRecovery(), SummarizeWAL(), and XlogReadTwoPhaseData().

◆ XLogReaderHasQueuedRecordOrError()

static bool XLogReaderHasQueuedRecordOrError ( XLogReaderState * state )

inlinestatic

Definition at line 325 of file xlogreader.h.

{
    return (state->decode_queue_head != NULL) || state->errormsg_deferred;
}

Referenced by XLogPrefetcherNextBlock(), XLogPrefetcherReadRecord(), and XLogReadRecord().

◆ XLogReaderResetError()

void XLogReaderResetError ( XLogReaderState * state )

Definition at line 1366 of file xlogreader.c.

{
    state->errormsg_buf[0] = '\0';
    state->errormsg_deferred = false;
}

Referenced by XLogPageRead().

◆ XLogReaderSetDecodeBuffer()

void XLogReaderSetDecodeBuffer	(	XLogReaderState *	state,
		void *	buffer,
		size_t	size
	)

Definition at line 91 of file xlogreader.c.

{
    Assert(state->decode_buffer == NULL);
 
    state->decode_buffer = buffer;
    state->decode_buffer_size = size;
    state->decode_buffer_tail = buffer;
    state->decode_buffer_head = buffer;
}

References Assert().

Referenced by InitWalRecovery().

◆ XLogReaderValidatePageHeader()

bool XLogReaderValidatePageHeader	(	XLogReaderState *	state,
		XLogRecPtr	recptr,
		char *	phdr
	)

Definition at line 1225 of file xlogreader.c.

{
    XLogSegNo   segno;
    int32       offset;
    XLogPageHeader hdr = (XLogPageHeader) phdr;
 
    Assert((recptr % XLOG_BLCKSZ) == 0);
 
    XLByteToSeg(recptr, segno, state->segcxt.ws_segsize);
    offset = XLogSegmentOffset(recptr, state->segcxt.ws_segsize);
 
    if (hdr->xlp_magic != XLOG_PAGE_MAGIC)
    {
        char        fname[MAXFNAMELEN];
 
        XLogFileName(fname, state->seg.ws_tli, segno, state->segcxt.ws_segsize);
 
        report_invalid_record(state,
                              "invalid magic number %04X in WAL segment %s, LSN %X/%X, offset %u",
                              hdr->xlp_magic,
                              fname,
                              LSN_FORMAT_ARGS(recptr),
                              offset);
        return false;
    }
 
    if ((hdr->xlp_info & ~XLP_ALL_FLAGS) != 0)
    {
        char        fname[MAXFNAMELEN];
 
        XLogFileName(fname, state->seg.ws_tli, segno, state->segcxt.ws_segsize);
 
        report_invalid_record(state,
                              "invalid info bits %04X in WAL segment %s, LSN %X/%X, offset %u",
                              hdr->xlp_info,
                              fname,
                              LSN_FORMAT_ARGS(recptr),
                              offset);
        return false;
    }
 
    if (hdr->xlp_info & XLP_LONG_HEADER)
    {
        XLogLongPageHeader longhdr = (XLogLongPageHeader) hdr;
 
        if (state->system_identifier &&
            longhdr->xlp_sysid != state->system_identifier)
        {
            report_invalid_record(state,
                                  "WAL file is from different database system: WAL file database system identifier is %" PRIu64 ", pg_control database system identifier is %" PRIu64,
                                  longhdr->xlp_sysid,
                                  state->system_identifier);
            return false;
        }
        else if (longhdr->xlp_seg_size != state->segcxt.ws_segsize)
        {
            report_invalid_record(state,
                                  "WAL file is from different database system: incorrect segment size in page header");
            return false;
        }
        else if (longhdr->xlp_xlog_blcksz != XLOG_BLCKSZ)
        {
            report_invalid_record(state,
                                  "WAL file is from different database system: incorrect XLOG_BLCKSZ in page header");
            return false;
        }
    }
    else if (offset == 0)
    {
        char        fname[MAXFNAMELEN];
 
        XLogFileName(fname, state->seg.ws_tli, segno, state->segcxt.ws_segsize);
 
        /* hmm, first page of file doesn't have a long header? */
        report_invalid_record(state,
                              "invalid info bits %04X in WAL segment %s, LSN %X/%X, offset %u",
                              hdr->xlp_info,
                              fname,
                              LSN_FORMAT_ARGS(recptr),
                              offset);
        return false;
    }
 
    /*
     * Check that the address on the page agrees with what we expected. This
     * check typically fails when an old WAL segment is recycled, and hasn't
     * yet been overwritten with new data yet.
     */
    if (hdr->xlp_pageaddr != recptr)
    {
        char        fname[MAXFNAMELEN];
 
        XLogFileName(fname, state->seg.ws_tli, segno, state->segcxt.ws_segsize);
 
        report_invalid_record(state,
                              "unexpected pageaddr %X/%X in WAL segment %s, LSN %X/%X, offset %u",
                              LSN_FORMAT_ARGS(hdr->xlp_pageaddr),
                              fname,
                              LSN_FORMAT_ARGS(recptr),
                              offset);
        return false;
    }
 
    /*
     * Since child timelines are always assigned a TLI greater than their
     * immediate parent's TLI, we should never see TLI go backwards across
     * successive pages of a consistent WAL sequence.
     *
     * Sometimes we re-read a segment that's already been (partially) read. So
     * we only verify TLIs for pages that are later than the last remembered
     * LSN.
     */
    if (recptr > state->latestPagePtr)
    {
        if (hdr->xlp_tli < state->latestPageTLI)
        {
            char        fname[MAXFNAMELEN];
 
            XLogFileName(fname, state->seg.ws_tli, segno, state->segcxt.ws_segsize);
 
            report_invalid_record(state,
                                  "out-of-sequence timeline ID %u (after %u) in WAL segment %s, LSN %X/%X, offset %u",
                                  hdr->xlp_tli,
                                  state->latestPageTLI,
                                  fname,
                                  LSN_FORMAT_ARGS(recptr),
                                  offset);
            return false;
        }
    }
    state->latestPagePtr = recptr;
    state->latestPageTLI = hdr->xlp_tli;
 
    return true;
}

References Assert(), LSN_FORMAT_ARGS, MAXFNAMELEN, report_invalid_record(), XLByteToSeg, XLOG_PAGE_MAGIC, XLogFileName(), XLogSegmentOffset, XLP_ALL_FLAGS, XLogPageHeaderData::xlp_info, XLP_LONG_HEADER, XLogPageHeaderData::xlp_magic, XLogPageHeaderData::xlp_pageaddr, XLogLongPageHeaderData::xlp_seg_size, XLogLongPageHeaderData::xlp_sysid, XLogPageHeaderData::xlp_tli, and XLogLongPageHeaderData::xlp_xlog_blcksz.

Referenced by ReadPageInternal(), and XLogPageRead().

◆ XLogReadRecord()

struct XLogRecord * XLogReadRecord	(	XLogReaderState *	state,
		char **	errormsg
	)

Definition at line 390 of file xlogreader.c.

{
    DecodedXLogRecord *decoded;
 
    /*
     * Release last returned record, if there is one.  We need to do this so
     * that we can check for empty decode queue accurately.
     */
    XLogReleasePreviousRecord(state);
 
    /*
     * Call XLogReadAhead() in blocking mode to make sure there is something
     * in the queue, though we don't use the result.
     */
    if (!XLogReaderHasQueuedRecordOrError(state))
        XLogReadAhead(state, false /* nonblocking */ );
 
    /* Consume the head record or error. */
    decoded = XLogNextRecord(state, errormsg);
    if (decoded)
    {
        /*
         * This function returns a pointer to the record's header, not the
         * actual decoded record.  The caller will access the decoded record
         * through the XLogRecGetXXX() macros, which reach the decoded
         * recorded as xlogreader->record.
         */
        Assert(state->record == decoded);
        return &decoded->header;
    }
 
    return NULL;
}

References Assert(), DecodedXLogRecord::header, XLogNextRecord(), XLogReadAhead(), XLogReaderHasQueuedRecordOrError(), and XLogReleasePreviousRecord().

Referenced by DecodingContextFindStartpoint(), extractPageMap(), findLastCheckpoint(), LogicalReplicationSlotHasPendingWal(), LogicalSlotAdvanceAndCheckSnapState(), main(), pg_logical_slot_get_changes_guts(), ReadNextXLogRecord(), readOneRecord(), SummarizeWAL(), XLogFindNextRecord(), XlogReadTwoPhaseData(), and XLogSendLogical().

◆ XLogRecGetBlockData()

char * XLogRecGetBlockData	(	XLogReaderState *	record,
		uint8	block_id,
		Size *	len
	)

Definition at line 2035 of file xlogreader.c.

{
    DecodedBkpBlock *bkpb;
 
    if (block_id > record->record->max_block_id ||
        !record->record->blocks[block_id].in_use)
        return NULL;
 
    bkpb = &record->record->blocks[block_id];
 
    if (!bkpb->has_data)
    {
        if (len)
            *len = 0;
        return NULL;
    }
    else
    {
        if (len)
            *len = bkpb->data_len;
        return bkpb->data;
    }
}

References DecodedXLogRecord::blocks, DecodedBkpBlock::data, DecodedBkpBlock::data_len, DecodedBkpBlock::has_data, DecodedBkpBlock::in_use, len, DecodedXLogRecord::max_block_id, and XLogReaderState::record.

Referenced by _bt_restore_meta(), brin_xlog_insert_update(), brin_xlog_samepage_update(), btree_desc(), btree_xlog_dedup(), btree_xlog_delete(), btree_xlog_insert(), btree_xlog_newroot(), btree_xlog_split(), btree_xlog_vacuum(), DecodeInsert(), DecodeMultiInsert(), DecodeUpdate(), generic_redo(), gin_desc(), ginRedoInsert(), ginRedoInsertListPage(), ginRedoUpdateMetapage(), ginRedoVacuumDataLeafPage(), gistRedoPageSplitRecord(), gistRedoPageUpdateRecord(), hash_xlog_add_ovfl_page(), hash_xlog_delete(), hash_xlog_insert(), hash_xlog_move_page_contents(), hash_xlog_split_allocate_page(), hash_xlog_squeeze_page(), heap2_desc(), heap_xlog_inplace(), heap_xlog_insert(), heap_xlog_multi_insert(), heap_xlog_prune_freeze(), and heap_xlog_update().

◆ XLogRecGetBlockTag()

void XLogRecGetBlockTag	(	XLogReaderState *	record,
		uint8	block_id,
		RelFileLocator *	rlocator,
		ForkNumber *	forknum,
		BlockNumber *	blknum
	)

Definition at line 1981 of file xlogreader.c.

{
    if (!XLogRecGetBlockTagExtended(record, block_id, rlocator, forknum,
                                    blknum, NULL))
    {
#ifndef FRONTEND
        elog(ERROR, "could not locate backup block with ID %d in WAL record",
             block_id);
#else
        pg_fatal("could not locate backup block with ID %d in WAL record",
                 block_id);
#endif
    }
}

References elog, ERROR, pg_fatal, and XLogRecGetBlockTagExtended().

Referenced by brin_xlog_revmap_extend(), btree_xlog_delete(), btree_xlog_split(), DecodeDelete(), DecodeInsert(), DecodeMultiInsert(), DecodeSpecConfirm(), DecodeUpdate(), gistRedoDeleteRecord(), gistRedoPageSplitRecord(), hash_xlog_add_ovfl_page(), hash_xlog_init_bitmap_page(), hash_xlog_init_meta_page(), hash_xlog_vacuum_one_page(), heap_xlog_delete(), heap_xlog_insert(), heap_xlog_lock(), heap_xlog_lock_updated(), heap_xlog_multi_insert(), heap_xlog_prune_freeze(), heap_xlog_update(), heap_xlog_visible(), spgRedoAddLeaf(), spgRedoAddNode(), spgRedoMoveLeafs(), spgRedoPickSplit(), and spgRedoVacuumRedirect().

◆ XLogRecGetBlockTagExtended()

bool XLogRecGetBlockTagExtended	(	XLogReaderState *	record,
		uint8	block_id,
		RelFileLocator *	rlocator,
		ForkNumber *	forknum,
		BlockNumber *	blknum,
		Buffer *	prefetch_buffer
	)

Definition at line 2007 of file xlogreader.c.

{
    DecodedBkpBlock *bkpb;
 
    if (!XLogRecHasBlockRef(record, block_id))
        return false;
 
    bkpb = &record->record->blocks[block_id];
    if (rlocator)
        *rlocator = bkpb->rlocator;
    if (forknum)
        *forknum = bkpb->forknum;
    if (blknum)
        *blknum = bkpb->blkno;
    if (prefetch_buffer)
        *prefetch_buffer = bkpb->prefetch_buffer;
    return true;
}

References DecodedBkpBlock::blkno, DecodedXLogRecord::blocks, DecodedBkpBlock::forknum, DecodedBkpBlock::prefetch_buffer, XLogReaderState::record, DecodedBkpBlock::rlocator, and XLogRecHasBlockRef.

Referenced by btree_xlog_split(), extractPageInfo(), GetWALBlockInfo(), heap_xlog_update(), SummarizeWAL(), verifyBackupPageConsistency(), xlog_block_info(), XLogReadBufferForRedoExtended(), XLogRecGetBlockRefInfo(), XLogRecGetBlockTag(), XLogRecordMatchesRelationBlock(), and XLogRecordSaveFPWs().

◆ XLogRecGetFullXid()

FullTransactionId XLogRecGetFullXid ( XLogReaderState * record )

Definition at line 2177 of file xlogreader.c.

{
    /*
     * This function is only safe during replay, because it depends on the
     * replay state.  See AdvanceNextFullTransactionIdPastXid() for more.
     */
    Assert(AmStartupProcess() || !IsUnderPostmaster);
 
    return FullTransactionIdFromAllowableAt(TransamVariables->nextXid,
                                            XLogRecGetXid(record));
}

References AmStartupProcess, Assert(), FullTransactionIdFromAllowableAt(), IsUnderPostmaster, TransamVariablesData::nextXid, TransamVariables, and XLogRecGetXid.

◆ XLogReleasePreviousRecord()

XLogRecPtr XLogReleasePreviousRecord ( XLogReaderState * state )

Definition at line 250 of file xlogreader.c.

{
    DecodedXLogRecord *record;
    XLogRecPtr  next_lsn;
 
    if (!state->record)
        return InvalidXLogRecPtr;
 
    /*
     * Remove it from the decoded record queue.  It must be the oldest item
     * decoded, decode_queue_head.
     */
    record = state->record;
    next_lsn = record->next_lsn;
    Assert(record == state->decode_queue_head);
    state->record = NULL;
    state->decode_queue_head = record->next;
 
    /* It might also be the newest item decoded, decode_queue_tail. */
    if (state->decode_queue_tail == record)
        state->decode_queue_tail = NULL;
 
    /* Release the space. */
    if (unlikely(record->oversized))
    {
        /* It's not in the decode buffer, so free it to release space. */
        pfree(record);
    }
    else
    {
        /* It must be the head (oldest) record in the decode buffer. */
        Assert(state->decode_buffer_head == (char *) record);
 
        /*
         * We need to update head to point to the next record that is in the
         * decode buffer, if any, being careful to skip oversized ones
         * (they're not in the decode buffer).
         */
        record = record->next;
        while (unlikely(record && record->oversized))
            record = record->next;
 
        if (record)
        {
            /* Adjust head to release space up to the next record. */
            state->decode_buffer_head = (char *) record;
        }
        else
        {
            /*
             * Otherwise we might as well just reset head and tail to the
             * start of the buffer space, because we're empty.  This means
             * we'll keep overwriting the same piece of memory if we're not
             * doing any prefetching.
             */
            state->decode_buffer_head = state->decode_buffer;
            state->decode_buffer_tail = state->decode_buffer;
        }
    }
 
    return next_lsn;
}

References Assert(), InvalidXLogRecPtr, DecodedXLogRecord::next, DecodedXLogRecord::next_lsn, DecodedXLogRecord::oversized, pfree(), and unlikely.

Referenced by XLogNextRecord(), XLogPrefetcherReadRecord(), and XLogReadRecord().

Data Structures

Macros

Typedefs

Enumerations

Functions

Macro Definition Documentation

◆ XL_ROUTINE

◆ XLogRecBlockImageApply

◆ XLogRecGetBlock

◆ XLogRecGetData

◆ XLogRecGetDataLen

◆ XLogRecGetInfo

◆ XLogRecGetOrigin

◆ XLogRecGetPrev

◆ XLogRecGetRmid

◆ XLogRecGetTopXid

◆ XLogRecGetTotalLen

◆ XLogRecGetXid

◆ XLogRecHasAnyBlockRefs

◆ XLogRecHasBlockData

◆ XLogRecHasBlockImage

◆ XLogRecHasBlockRef

◆ XLogRecMaxBlockId

Typedef Documentation

◆ DecodedXLogRecord

◆ WALOpenSegment

◆ WALReadError

◆ WALSegmentCloseCB

◆ WALSegmentContext

◆ WALSegmentOpenCB

◆ XLogPageReadCB

◆ XLogPageReadResult

◆ XLogReaderRoutine

◆ XLogReaderState

Enumeration Type Documentation

◆ XLogPageReadResult

Function Documentation

◆ DecodeXLogRecord()

◆ DecodeXLogRecordRequiredSpace()

◆ RestoreBlockImage()

◆ WALRead()

◆ XLogBeginRead()

◆ XLogFindNextRecord()

◆ XLogNextRecord()

◆ XLogReadAhead()

◆ XLogReaderAllocate()

◆ XLogReaderFree()

◆ XLogReaderHasQueuedRecordOrError()

◆ XLogReaderResetError()

◆ XLogReaderSetDecodeBuffer()

◆ XLogReaderValidatePageHeader()

◆ XLogReadRecord()

◆ XLogRecGetBlockData()

◆ XLogRecGetBlockTag()

◆ XLogRecGetBlockTagExtended()

◆ XLogRecGetFullXid()

◆ XLogReleasePreviousRecord()