storage_xlog.h File Reference

#include "access/xlogreader.h"
#include "lib/stringinfo.h"
#include "storage/block.h"
#include "storage/relfilenode.h"

Include dependency graph for storage_xlog.h:

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Data Structures
struct	xl_smgr_create
struct	xl_smgr_truncate

Macros
#define	XLOG_SMGR_CREATE   0x10
#define	XLOG_SMGR_TRUNCATE   0x20
#define	SMGR_TRUNCATE_HEAP   0x0001
#define	SMGR_TRUNCATE_VM   0x0002
#define	SMGR_TRUNCATE_FSM   0x0004
#define	SMGR_TRUNCATE_ALL   (SMGR_TRUNCATE_HEAP|SMGR_TRUNCATE_VM|SMGR_TRUNCATE_FSM)

Typedefs
typedef struct xl_smgr_create	xl_smgr_create
typedef struct xl_smgr_truncate	xl_smgr_truncate

Functions
void	log_smgrcreate (const RelFileNode *rnode, ForkNumber forkNum)
void	smgr_redo (XLogReaderState *record)
void	smgr_desc (StringInfo buf, XLogReaderState *record)
const char *	smgr_identify (uint8 info)

Macro Definition Documentation

SMGR_TRUNCATE_ALL

#define SMGR_TRUNCATE_ALL   (SMGR_TRUNCATE_HEAP|SMGR_TRUNCATE_VM|SMGR_TRUNCATE_FSM)

Definition at line 43 of file storage_xlog.h.

Referenced by RelationTruncate().

SMGR_TRUNCATE_FSM

#define SMGR_TRUNCATE_FSM   0x0004

Definition at line 42 of file storage_xlog.h.

Referenced by smgr_redo().

SMGR_TRUNCATE_HEAP

#define SMGR_TRUNCATE_HEAP   0x0001

Definition at line 40 of file storage_xlog.h.

Referenced by smgr_redo().

SMGR_TRUNCATE_VM

#define SMGR_TRUNCATE_VM   0x0002

Definition at line 41 of file storage_xlog.h.

Referenced by pg_truncate_visibility_map(), and smgr_redo().

XLOG_SMGR_CREATE

#define XLOG_SMGR_CREATE   0x10

Definition at line 30 of file storage_xlog.h.

Referenced by extractPageInfo(), log_smgrcreate(), smgr_desc(), smgr_identify(), and smgr_redo().

XLOG_SMGR_TRUNCATE

#define XLOG_SMGR_TRUNCATE   0x20

Definition at line 31 of file storage_xlog.h.

Referenced by extractPageInfo(), pg_truncate_visibility_map(), RelationTruncate(), smgr_desc(), smgr_identify(), and smgr_redo().

Typedef Documentation

xl_smgr_create

typedef struct xl_smgr_create xl_smgr_create

xl_smgr_truncate

typedef struct xl_smgr_truncate xl_smgr_truncate

Function Documentation

log_smgrcreate()

void log_smgrcreate	(	const RelFileNode *	rnode,
		ForkNumber	forkNum
	)

Definition at line 175 of file storage.c.

References xl_smgr_create::forkNum, xl_smgr_create::rnode, XLOG_SMGR_CREATE, XLogBeginInsert(), XLogInsert(), XLogRegisterData(), and XLR_SPECIAL_REL_UPDATE.

Referenced by heapam_relation_copy_data(), heapam_relation_set_new_filenode(), index_copy_data(), and RelationCreateStorage().

{
    xl_smgr_create xlrec;

    /*
     * Make an XLOG entry reporting the file creation.
     */
    xlrec.rnode = *rnode;
    xlrec.forkNum = forkNum;

    XLogBeginInsert();
    XLogRegisterData((char *) &xlrec, sizeof(xlrec));
    XLogInsert(RM_SMGR_ID, XLOG_SMGR_CREATE | XLR_SPECIAL_REL_UPDATE);
}

smgr_desc()

void smgr_desc	(	StringInfo	buf,
		XLogReaderState *	record
	)

Definition at line 21 of file smgrdesc.c.

References appendStringInfo(), appendStringInfoString(), xl_smgr_truncate::blkno, xl_smgr_truncate::flags, xl_smgr_create::forkNum, MAIN_FORKNUM, pfree(), relpathperm, xl_smgr_create::rnode, xl_smgr_truncate::rnode, XLOG_SMGR_CREATE, XLOG_SMGR_TRUNCATE, XLogRecGetData, XLogRecGetInfo, and XLR_INFO_MASK.

{
    char       *rec = XLogRecGetData(record);
    uint8       info = XLogRecGetInfo(record) & ~XLR_INFO_MASK;

    if (info == XLOG_SMGR_CREATE)
    {
        xl_smgr_create *xlrec = (xl_smgr_create *) rec;
        char       *path = relpathperm(xlrec->rnode, xlrec->forkNum);

        appendStringInfoString(buf, path);
        pfree(path);
    }
    else if (info == XLOG_SMGR_TRUNCATE)
    {
        xl_smgr_truncate *xlrec = (xl_smgr_truncate *) rec;
        char       *path = relpathperm(xlrec->rnode, MAIN_FORKNUM);

        appendStringInfo(buf, "%s to %u blocks flags %d", path,
                         xlrec->blkno, xlrec->flags);
        pfree(path);
    }
}

smgr_identify()

const char* smgr_identify

(

uint8

info

)

Definition at line 46 of file smgrdesc.c.

References XLOG_SMGR_CREATE, XLOG_SMGR_TRUNCATE, and XLR_INFO_MASK.

{
    const char *id = NULL;

    switch (info & ~XLR_INFO_MASK)
    {
        case XLOG_SMGR_CREATE:
            id = "CREATE";
            break;
        case XLOG_SMGR_TRUNCATE:
            id = "TRUNCATE";
            break;
    }

    return id;
}

smgr_redo()

void smgr_redo

(

XLogReaderState *

record

)

Definition at line 904 of file storage.c.

References Assert, xl_smgr_truncate::blkno, BlockNumberIsValid, blocks, CreateFakeRelcacheEntry(), elog, XLogReaderState::EndRecPtr, xl_smgr_truncate::flags, xl_smgr_create::forkNum, FreeFakeRelcacheEntry(), FreeSpaceMapPrepareTruncateRel(), FreeSpaceMapVacuumRange(), FSM_FORKNUM, InvalidBackendId, InvalidBlockNumber, MAIN_FORKNUM, MAX_FORKNUM, PANIC, xl_smgr_create::rnode, xl_smgr_truncate::rnode, SMGR_TRUNCATE_FSM, SMGR_TRUNCATE_HEAP, SMGR_TRUNCATE_VM, smgrcreate(), smgrexists(), smgropen(), smgrtruncate(), VISIBILITYMAP_FORKNUM, visibilitymap_prepare_truncate(), XLOG_SMGR_CREATE, XLOG_SMGR_TRUNCATE, XLogFlush(), XLogRecGetData, XLogRecGetInfo, XLogRecHasAnyBlockRefs, XLogTruncateRelation(), and XLR_INFO_MASK.

{
    XLogRecPtr  lsn = record->EndRecPtr;
    uint8       info = XLogRecGetInfo(record) & ~XLR_INFO_MASK;

    /* Backup blocks are not used in smgr records */
    Assert(!XLogRecHasAnyBlockRefs(record));

    if (info == XLOG_SMGR_CREATE)
    {
        xl_smgr_create *xlrec = (xl_smgr_create *) XLogRecGetData(record);
        SMgrRelation reln;

        reln = smgropen(xlrec->rnode, InvalidBackendId);
        smgrcreate(reln, xlrec->forkNum, true);
    }
    else if (info == XLOG_SMGR_TRUNCATE)
    {
        xl_smgr_truncate *xlrec = (xl_smgr_truncate *) XLogRecGetData(record);
        SMgrRelation reln;
        Relation    rel;
        ForkNumber  forks[MAX_FORKNUM];
        BlockNumber blocks[MAX_FORKNUM];
        int         nforks = 0;
        bool        need_fsm_vacuum = false;

        reln = smgropen(xlrec->rnode, InvalidBackendId);

        /*
         * Forcibly create relation if it doesn't exist (which suggests that
         * it was dropped somewhere later in the WAL sequence).  As in
         * XLogReadBufferForRedo, we prefer to recreate the rel and replay the
         * log as best we can until the drop is seen.
         */
        smgrcreate(reln, MAIN_FORKNUM, true);

        /*
         * Before we perform the truncation, update minimum recovery point to
         * cover this WAL record. Once the relation is truncated, there's no
         * going back. The buffer manager enforces the WAL-first rule for
         * normal updates to relation files, so that the minimum recovery
         * point is always updated before the corresponding change in the data
         * file is flushed to disk. We have to do the same manually here.
         *
         * Doing this before the truncation means that if the truncation fails
         * for some reason, you cannot start up the system even after restart,
         * until you fix the underlying situation so that the truncation will
         * succeed. Alternatively, we could update the minimum recovery point
         * after truncation, but that would leave a small window where the
         * WAL-first rule could be violated.
         */
        XLogFlush(lsn);

        /* Prepare for truncation of MAIN fork */
        if ((xlrec->flags & SMGR_TRUNCATE_HEAP) != 0)
        {
            forks[nforks] = MAIN_FORKNUM;
            blocks[nforks] = xlrec->blkno;
            nforks++;

            /* Also tell xlogutils.c about it */
            XLogTruncateRelation(xlrec->rnode, MAIN_FORKNUM, xlrec->blkno);
        }

        /* Prepare for truncation of FSM and VM too */
        rel = CreateFakeRelcacheEntry(xlrec->rnode);

        if ((xlrec->flags & SMGR_TRUNCATE_FSM) != 0 &&
            smgrexists(reln, FSM_FORKNUM))
        {
            blocks[nforks] = FreeSpaceMapPrepareTruncateRel(rel, xlrec->blkno);
            if (BlockNumberIsValid(blocks[nforks]))
            {
                forks[nforks] = FSM_FORKNUM;
                nforks++;
                need_fsm_vacuum = true;
            }
        }
        if ((xlrec->flags & SMGR_TRUNCATE_VM) != 0 &&
            smgrexists(reln, VISIBILITYMAP_FORKNUM))
        {
            blocks[nforks] = visibilitymap_prepare_truncate(rel, xlrec->blkno);
            if (BlockNumberIsValid(blocks[nforks]))
            {
                forks[nforks] = VISIBILITYMAP_FORKNUM;
                nforks++;
            }
        }

        /* Do the real work to truncate relation forks */
        if (nforks > 0)
            smgrtruncate(reln, forks, nforks, blocks);

        /*
         * Update upper-level FSM pages to account for the truncation. This is
         * important because the just-truncated pages were likely marked as
         * all-free, and would be preferentially selected.
         */
        if (need_fsm_vacuum)
            FreeSpaceMapVacuumRange(rel, xlrec->blkno,
                                    InvalidBlockNumber);

        FreeFakeRelcacheEntry(rel);
    }
    else
        elog(PANIC, "smgr_redo: unknown op code %u", info);
}