sequence_xlog.h File Reference

#include "access/xlogreader.h"
#include "lib/stringinfo.h"

Include dependency graph for sequence_xlog.h:

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Data Structures
struct	sequence_magic
struct	xl_seq_rec

Macros
#define	XLOG_SEQ_LOG   0x00
#define	SEQ_MAGIC   0x1717

Typedefs
typedef struct sequence_magic	sequence_magic
typedef struct xl_seq_rec	xl_seq_rec

Functions
void	seq_redo (XLogReaderState *record)
void	seq_desc (StringInfo buf, XLogReaderState *record)
const char *	seq_identify (uint8 info)
void	seq_mask (char *page, BlockNumber blkno)

Macro Definition Documentation

SEQ_MAGIC

#define SEQ_MAGIC   0x1717

Definition at line 26 of file sequence_xlog.h.

XLOG_SEQ_LOG

#define XLOG_SEQ_LOG   0x00

Definition at line 21 of file sequence_xlog.h.

Typedef Documentation

sequence_magic

typedef struct sequence_magic sequence_magic

xl_seq_rec

typedef struct xl_seq_rec xl_seq_rec

Function Documentation

seq_desc()

void seq_desc ( StringInfo  buf, XLogReaderState *  record  )

extern

Definition at line 21 of file seqdesc.c.

{
    char       *rec = XLogRecGetData(record);
    uint8       info = XLogRecGetInfo(record) & ~XLR_INFO_MASK;
    xl_seq_rec *xlrec = (xl_seq_rec *) rec;
 
    if (info == XLOG_SEQ_LOG)
        appendStringInfo(buf, "rel %u/%u/%u",
                         xlrec->locator.spcOid, xlrec->locator.dbOid,
                         xlrec->locator.relNumber);
}

References appendStringInfo(), buf, fb(), XLOG_SEQ_LOG, XLogRecGetData, and XLogRecGetInfo.

seq_identify()

const char * seq_identify ( uint8  info )

extern

Definition at line 34 of file seqdesc.c.

{
    const char *id = NULL;
 
    switch (info & ~XLR_INFO_MASK)
    {
        case XLOG_SEQ_LOG:
            id = "LOG";
            break;
    }
 
    return id;
}

References fb(), XLOG_SEQ_LOG, and XLR_INFO_MASK.

seq_mask()

void seq_mask ( char *  page, BlockNumber  blkno  )

extern

Definition at line 75 of file sequence_xlog.c.

{
    mask_page_lsn_and_checksum(page);
 
    mask_unused_space(page);
}

References mask_page_lsn_and_checksum(), and mask_unused_space().

seq_redo()

void seq_redo ( XLogReaderState *  record )

extern

Definition at line 23 of file sequence_xlog.c.

{
    XLogRecPtr  lsn = record->EndRecPtr;
    uint8       info = XLogRecGetInfo(record) & ~XLR_INFO_MASK;
    Buffer      buffer;
    Page        page;
    Page        localpage;
    char       *item;
    Size        itemsz;
    xl_seq_rec *xlrec = (xl_seq_rec *) XLogRecGetData(record);
    sequence_magic *sm;
 
    if (info != XLOG_SEQ_LOG)
        elog(PANIC, "seq_redo: unknown op code %u", info);
 
    buffer = XLogInitBufferForRedo(record, 0);
    page = BufferGetPage(buffer);
 
    /*
     * We always reinit the page.  However, since this WAL record type is also
     * used for updating sequences, it's possible that a hot-standby backend
     * is examining the page concurrently; so we mustn't transiently trash the
     * buffer.  The solution is to build the correct new page contents in
     * local workspace and then memcpy into the buffer.  Then only bytes that
     * are supposed to change will change, even transiently. We must palloc
     * the local page for alignment reasons.
     */
    localpage = (Page) palloc(BufferGetPageSize(buffer));
 
    PageInit(localpage, BufferGetPageSize(buffer), sizeof(sequence_magic));
    sm = (sequence_magic *) PageGetSpecialPointer(localpage);
    sm->magic = SEQ_MAGIC;
 
    item = (char *) xlrec + sizeof(xl_seq_rec);
    itemsz = XLogRecGetDataLen(record) - sizeof(xl_seq_rec);
 
    if (PageAddItem(localpage, item, itemsz, FirstOffsetNumber, false, false) == InvalidOffsetNumber)
        elog(PANIC, "seq_redo: failed to add item to page");
 
    PageSetLSN(localpage, lsn);
 
    memcpy(page, localpage, BufferGetPageSize(buffer));
    MarkBufferDirty(buffer);
    UnlockReleaseBuffer(buffer);
 
    pfree(localpage);
}

References BufferGetPage(), BufferGetPageSize(), elog, XLogReaderState::EndRecPtr, fb(), FirstOffsetNumber, InvalidOffsetNumber, sequence_magic::magic, MarkBufferDirty(), PageAddItem, PageGetSpecialPointer, PageInit(), PageSetLSN(), palloc(), PANIC, pfree(), SEQ_MAGIC, UnlockReleaseBuffer(), XLOG_SEQ_LOG, XLogInitBufferForRedo(), XLogRecGetData, XLogRecGetDataLen, and XLogRecGetInfo.