verify_heapam.c File Reference

#include "postgres.h"
#include "access/detoast.h"
#include "access/genam.h"
#include "access/heapam.h"
#include "access/heaptoast.h"
#include "access/multixact.h"
#include "access/toast_internals.h"
#include "access/visibilitymap.h"
#include "catalog/pg_am.h"
#include "funcapi.h"
#include "miscadmin.h"
#include "storage/bufmgr.h"
#include "storage/procarray.h"
#include "utils/builtins.h"
#include "utils/fmgroids.h"

Include dependency graph for verify_heapam.c:

Go to the source code of this file.

Data Structures
struct	HeapCheckContext

Macros
#define	HEAPCHECK_RELATION_COLS   4

Typedefs
typedef enum XidBoundsViolation	XidBoundsViolation
typedef enum XidCommitStatus	XidCommitStatus
typedef enum SkipPages	SkipPages
typedef struct HeapCheckContext	HeapCheckContext

Enumerations
enum	XidBoundsViolation {   XID_INVALID, XID_IN_FUTURE, XID_PRECEDES_CLUSTERMIN, XID_PRECEDES_RELMIN,   XID_BOUNDS_OK }
enum	XidCommitStatus { XID_COMMITTED, XID_IN_PROGRESS, XID_ABORTED }
enum	SkipPages { SKIP_PAGES_ALL_FROZEN, SKIP_PAGES_ALL_VISIBLE, SKIP_PAGES_NONE }

Functions
	PG_FUNCTION_INFO_V1 (verify_heapam)
static void	sanity_check_relation (Relation rel)
static void	check_tuple (HeapCheckContext *ctx)
static void	check_toast_tuple (HeapTuple toasttup, HeapCheckContext *ctx)
static bool	check_tuple_attribute (HeapCheckContext *ctx)
static bool	check_tuple_header_and_visibilty (HeapTupleHeader tuphdr, HeapCheckContext *ctx)
static void	report_corruption (HeapCheckContext *ctx, char *msg)
static TupleDesc	verify_heapam_tupdesc (void)
static FullTransactionId	FullTransactionIdFromXidAndCtx (TransactionId xid, const HeapCheckContext *ctx)
static void	update_cached_xid_range (HeapCheckContext *ctx)
static void	update_cached_mxid_range (HeapCheckContext *ctx)
static XidBoundsViolation	check_mxid_in_range (MultiXactId mxid, HeapCheckContext *ctx)
static XidBoundsViolation	check_mxid_valid_in_rel (MultiXactId mxid, HeapCheckContext *ctx)
static XidBoundsViolation	get_xid_status (TransactionId xid, HeapCheckContext *ctx, XidCommitStatus *status)
Datum	verify_heapam (PG_FUNCTION_ARGS)
static bool	fxid_in_cached_range (FullTransactionId fxid, const HeapCheckContext *ctx)

Macro Definition Documentation

HEAPCHECK_RELATION_COLS

#define HEAPCHECK_RELATION_COLS   4

Definition at line 31 of file verify_heapam.c.

Referenced by report_corruption(), and verify_heapam_tupdesc().

Typedef Documentation

HeapCheckContext

typedef struct HeapCheckContext HeapCheckContext

SkipPages

typedef enum SkipPages SkipPages

XidBoundsViolation

typedef enum XidBoundsViolation XidBoundsViolation

XidCommitStatus

typedef enum XidCommitStatus XidCommitStatus

Enumeration Type Documentation

SkipPages

enum SkipPages

Enumerator
SKIP_PAGES_ALL_FROZEN
SKIP_PAGES_ALL_VISIBLE
SKIP_PAGES_NONE

Definition at line 53 of file verify_heapam.c.

{
    SKIP_PAGES_ALL_FROZEN,
    SKIP_PAGES_ALL_VISIBLE,
    SKIP_PAGES_NONE
} SkipPages;

XidBoundsViolation

enum XidBoundsViolation

Enumerator
XID_INVALID
XID_IN_FUTURE
XID_PRECEDES_CLUSTERMIN
XID_PRECEDES_RELMIN
XID_BOUNDS_OK

Definition at line 37 of file verify_heapam.c.

{
    XID_INVALID,
    XID_IN_FUTURE,
    XID_PRECEDES_CLUSTERMIN,
    XID_PRECEDES_RELMIN,
    XID_BOUNDS_OK
} XidBoundsViolation;

XidCommitStatus

enum XidCommitStatus

Enumerator
XID_COMMITTED
XID_IN_PROGRESS
XID_ABORTED

Definition at line 46 of file verify_heapam.c.

{
    XID_COMMITTED,
    XID_IN_PROGRESS,
    XID_ABORTED
} XidCommitStatus;

Function Documentation

check_mxid_in_range()

static XidBoundsViolation check_mxid_in_range ( MultiXactId  mxid, HeapCheckContext *  ctx  )

static

Definition at line 1342 of file verify_heapam.c.

References MultiXactIdPrecedes(), MultiXactIdPrecedesOrEquals(), HeapCheckContext::next_mxact, HeapCheckContext::oldest_mxact, HeapCheckContext::relminmxid, TransactionIdIsValid, XID_BOUNDS_OK, XID_IN_FUTURE, XID_INVALID, XID_PRECEDES_CLUSTERMIN, and XID_PRECEDES_RELMIN.

Referenced by check_mxid_valid_in_rel().

{
    if (!TransactionIdIsValid(mxid))
        return XID_INVALID;
    if (MultiXactIdPrecedes(mxid, ctx->relminmxid))
        return XID_PRECEDES_RELMIN;
    if (MultiXactIdPrecedes(mxid, ctx->oldest_mxact))
        return XID_PRECEDES_CLUSTERMIN;
    if (MultiXactIdPrecedesOrEquals(ctx->next_mxact, mxid))
        return XID_IN_FUTURE;
    return XID_BOUNDS_OK;
}

check_mxid_valid_in_rel()

static XidBoundsViolation check_mxid_valid_in_rel ( MultiXactId  mxid, HeapCheckContext *  ctx  )

static

Definition at line 1364 of file verify_heapam.c.

References check_mxid_in_range(), update_cached_mxid_range(), and XID_BOUNDS_OK.

Referenced by check_tuple().

{
    XidBoundsViolation result;

    result = check_mxid_in_range(mxid, ctx);
    if (result == XID_BOUNDS_OK)
        return XID_BOUNDS_OK;

    /* The range may have advanced.  Recheck. */
    update_cached_mxid_range(ctx);
    return check_mxid_in_range(mxid, ctx);
}

check_toast_tuple()

static void check_toast_tuple ( HeapTuple  toasttup, HeapCheckContext *  ctx  )

static

Definition at line 829 of file verify_heapam.c.

References HeapCheckContext::attrsize, HeapCheckContext::chunkno, DatumGetInt32, DatumGetPointer, HeapCheckContext::endchunk, fastgetattr, header(), psprintf(), pstrdup(), RelationData::rd_att, report_corruption(), TOAST_MAX_CHUNK_SIZE, HeapCheckContext::toast_rel, HeapCheckContext::totalchunks, VARATT_IS_EXTENDED, VARATT_IS_SHORT, VARHDRSZ, VARHDRSZ_SHORT, VARSIZE, and VARSIZE_SHORT.

Referenced by check_tuple_attribute().

{
    int32       curchunk;
    Pointer     chunk;
    bool        isnull;
    int32       chunksize;
    int32       expected_size;

    /*
     * Have a chunk, extract the sequence number and the data
     */
    curchunk = DatumGetInt32(fastgetattr(toasttup, 2,
                                         ctx->toast_rel->rd_att, &isnull));
    if (isnull)
    {
        report_corruption(ctx,
                          pstrdup("toast chunk sequence number is null"));
        return;
    }
    chunk = DatumGetPointer(fastgetattr(toasttup, 3,
                                        ctx->toast_rel->rd_att, &isnull));
    if (isnull)
    {
        report_corruption(ctx,
                          pstrdup("toast chunk data is null"));
        return;
    }
    if (!VARATT_IS_EXTENDED(chunk))
        chunksize = VARSIZE(chunk) - VARHDRSZ;
    else if (VARATT_IS_SHORT(chunk))
    {
        /*
         * could happen due to heap_form_tuple doing its thing
         */
        chunksize = VARSIZE_SHORT(chunk) - VARHDRSZ_SHORT;
    }
    else
    {
        /* should never happen */
        uint32      header = ((varattrib_4b *) chunk)->va_4byte.va_header;

        report_corruption(ctx,
                          psprintf("corrupt extended toast chunk has invalid varlena header: %0x (sequence number %d)",
                                   header, curchunk));
        return;
    }

    /*
     * Some checks on the data we've found
     */
    if (curchunk != ctx->chunkno)
    {
        report_corruption(ctx,
                          psprintf("toast chunk sequence number %u does not match the expected sequence number %u",
                                   curchunk, ctx->chunkno));
        return;
    }
    if (curchunk > ctx->endchunk)
    {
        report_corruption(ctx,
                          psprintf("toast chunk sequence number %u exceeds the end chunk sequence number %u",
                                   curchunk, ctx->endchunk));
        return;
    }

    expected_size = curchunk < ctx->totalchunks - 1 ? TOAST_MAX_CHUNK_SIZE
        : ctx->attrsize - ((ctx->totalchunks - 1) * TOAST_MAX_CHUNK_SIZE);
    if (chunksize != expected_size)
    {
        report_corruption(ctx,
                          psprintf("toast chunk size %u differs from the expected size %u",
                                   chunksize, expected_size));
        return;
    }
}

check_tuple()

static void check_tuple ( HeapCheckContext *  ctx )

static

Definition at line 1121 of file verify_heapam.c.

References HeapCheckContext::attnum, check_mxid_valid_in_rel(), check_tuple_attribute(), check_tuple_header_and_visibilty(), EpochFromFullTransactionId, fatal, get_xid_status(), HEAP_XMAX_IS_MULTI, HeapTupleHeaderGetRawXmax, HeapTupleHeaderGetXmin, HeapCheckContext::natts, HeapCheckContext::next_fxid, HeapCheckContext::next_mxact, HeapCheckContext::offset, HeapCheckContext::oldest_fxid, HeapCheckContext::oldest_mxact, psprintf(), pstrdup(), HeapCheckContext::rel, RelationGetDescr, HeapCheckContext::relfrozenfxid, HeapCheckContext::relminmxid, report_corruption(), HeapTupleHeaderData::t_infomask, HeapCheckContext::tuphdr, XID_BOUNDS_OK, XID_IN_FUTURE, XID_INVALID, XID_PRECEDES_CLUSTERMIN, XID_PRECEDES_RELMIN, and XidFromFullTransactionId.

Referenced by verify_heapam().

{
    TransactionId xmin;
    TransactionId xmax;
    bool        fatal = false;
    uint16      infomask = ctx->tuphdr->t_infomask;

    /* If xmin is normal, it should be within valid range */
    xmin = HeapTupleHeaderGetXmin(ctx->tuphdr);
    switch (get_xid_status(xmin, ctx, NULL))
    {
        case XID_INVALID:
        case XID_BOUNDS_OK:
            break;
        case XID_IN_FUTURE:
            report_corruption(ctx,
                              psprintf("xmin %u equals or exceeds next valid transaction ID %u:%u",
                                       xmin,
                                       EpochFromFullTransactionId(ctx->next_fxid),
                                       XidFromFullTransactionId(ctx->next_fxid)));
            fatal = true;
            break;
        case XID_PRECEDES_CLUSTERMIN:
            report_corruption(ctx,
                              psprintf("xmin %u precedes oldest valid transaction ID %u:%u",
                                       xmin,
                                       EpochFromFullTransactionId(ctx->oldest_fxid),
                                       XidFromFullTransactionId(ctx->oldest_fxid)));
            fatal = true;
            break;
        case XID_PRECEDES_RELMIN:
            report_corruption(ctx,
                              psprintf("xmin %u precedes relation freeze threshold %u:%u",
                                       xmin,
                                       EpochFromFullTransactionId(ctx->relfrozenfxid),
                                       XidFromFullTransactionId(ctx->relfrozenfxid)));
            fatal = true;
            break;
    }

    xmax = HeapTupleHeaderGetRawXmax(ctx->tuphdr);

    if (infomask & HEAP_XMAX_IS_MULTI)
    {
        /* xmax is a multixact, so it should be within valid MXID range */
        switch (check_mxid_valid_in_rel(xmax, ctx))
        {
            case XID_INVALID:
                report_corruption(ctx,
                                  pstrdup("multitransaction ID is invalid"));
                fatal = true;
                break;
            case XID_PRECEDES_RELMIN:
                report_corruption(ctx,
                                  psprintf("multitransaction ID %u precedes relation minimum multitransaction ID threshold %u",
                                           xmax, ctx->relminmxid));
                fatal = true;
                break;
            case XID_PRECEDES_CLUSTERMIN:
                report_corruption(ctx,
                                  psprintf("multitransaction ID %u precedes oldest valid multitransaction ID threshold %u",
                                           xmax, ctx->oldest_mxact));
                fatal = true;
                break;
            case XID_IN_FUTURE:
                report_corruption(ctx,
                                  psprintf("multitransaction ID %u equals or exceeds next valid multitransaction ID %u",
                                           xmax,
                                           ctx->next_mxact));
                fatal = true;
                break;
            case XID_BOUNDS_OK:
                break;
        }
    }
    else
    {
        /*
         * xmax is not a multixact and is normal, so it should be within the
         * valid XID range.
         */
        switch (get_xid_status(xmax, ctx, NULL))
        {
            case XID_INVALID:
            case XID_BOUNDS_OK:
                break;
            case XID_IN_FUTURE:
                report_corruption(ctx,
                                  psprintf("xmax %u equals or exceeds next valid transaction ID %u:%u",
                                           xmax,
                                           EpochFromFullTransactionId(ctx->next_fxid),
                                           XidFromFullTransactionId(ctx->next_fxid)));
                fatal = true;
                break;
            case XID_PRECEDES_CLUSTERMIN:
                report_corruption(ctx,
                                  psprintf("xmax %u precedes oldest valid transaction ID %u:%u",
                                           xmax,
                                           EpochFromFullTransactionId(ctx->oldest_fxid),
                                           XidFromFullTransactionId(ctx->oldest_fxid)));
                fatal = true;
                break;
            case XID_PRECEDES_RELMIN:
                report_corruption(ctx,
                                  psprintf("xmax %u precedes relation freeze threshold %u:%u",
                                           xmax,
                                           EpochFromFullTransactionId(ctx->relfrozenfxid),
                                           XidFromFullTransactionId(ctx->relfrozenfxid)));
                fatal = true;
        }
    }

    /*
     * Cannot process tuple data if tuple header was corrupt, as the offsets
     * within the page cannot be trusted, leaving too much risk of reading
     * garbage if we continue.
     *
     * We also cannot process the tuple if the xmin or xmax were invalid
     * relative to relfrozenxid or relminmxid, as clog entries for the xids
     * may already be gone.
     */
    if (fatal)
        return;

    /*
     * Check various forms of tuple header corruption.  If the header is too
     * corrupt to continue checking, or if the tuple is not visible to anyone,
     * we cannot continue with other checks.
     */
    if (!check_tuple_header_and_visibilty(ctx->tuphdr, ctx))
        return;

    /*
     * The tuple is visible, so it must be compatible with the current version
     * of the relation descriptor. It might have fewer columns than are
     * present in the relation descriptor, but it cannot have more.
     */
    if (RelationGetDescr(ctx->rel)->natts < ctx->natts)
    {
        report_corruption(ctx,
                          psprintf("number of attributes %u exceeds maximum expected for table %u",
                                   ctx->natts,
                                   RelationGetDescr(ctx->rel)->natts));
        return;
    }

    /*
     * Check each attribute unless we hit corruption that confuses what to do
     * next, at which point we abort further attribute checks for this tuple.
     * Note that we don't abort for all types of corruption, only for those
     * types where we don't know how to continue.
     */
    ctx->offset = 0;
    for (ctx->attnum = 0; ctx->attnum < ctx->natts; ctx->attnum++)
        if (!check_tuple_attribute(ctx))
            break;              /* cannot continue */

    /* revert attnum to -1 until we again examine individual attributes */
    ctx->attnum = -1;
}

check_tuple_attribute()

static bool check_tuple_attribute ( HeapCheckContext *  ctx )

static

Definition at line 926 of file verify_heapam.c.

References att_addlength_pointer, att_align_nominal, att_align_pointer, att_isnull, HeapCheckContext::attnum, HeapCheckContext::attrsize, BTEqualStrategyNumber, check_toast_tuple(), HeapCheckContext::chunkno, DatumGetPointer, HeapCheckContext::endchunk, fetchatt, ForwardScanDirection, HEAP_HASEXTERNAL, HEAP_HASNULL, init_toast_snapshot(), HeapCheckContext::lp_len, ObjectIdGetDatum, HeapCheckContext::offset, psprintf(), RelationData::rd_rel, HeapCheckContext::rel, RelationGetDescr, report_corruption(), ScanKeyInit(), systable_beginscan_ordered(), systable_endscan_ordered(), systable_getnext_ordered(), HeapTupleHeaderData::t_bits, HeapTupleHeaderData::t_hoff, HeapTupleHeaderData::t_infomask, TOAST_MAX_CHUNK_SIZE, HeapCheckContext::toast_rel, HeapCheckContext::totalchunks, HeapCheckContext::tuphdr, TupleDescAttr, varatt_external::va_extsize, varatt_external::va_valueid, HeapCheckContext::valid_toast_index, VARATT_EXTERNAL_GET_POINTER, VARATT_IS_EXTERNAL, VARTAG_EXTERNAL, and VARTAG_ONDISK.

Referenced by check_tuple().

{
    struct varatt_external toast_pointer;
    ScanKeyData toastkey;
    SysScanDesc toastscan;
    SnapshotData SnapshotToast;
    HeapTuple   toasttup;
    bool        found_toasttup;
    Datum       attdatum;
    struct varlena *attr;
    char       *tp;             /* pointer to the tuple data */
    uint16      infomask;
    Form_pg_attribute thisatt;

    infomask = ctx->tuphdr->t_infomask;
    thisatt = TupleDescAttr(RelationGetDescr(ctx->rel), ctx->attnum);

    tp = (char *) ctx->tuphdr + ctx->tuphdr->t_hoff;

    if (ctx->tuphdr->t_hoff + ctx->offset > ctx->lp_len)
    {
        report_corruption(ctx,
                          psprintf("attribute %u with length %u starts at offset %u beyond total tuple length %u",
                                   ctx->attnum,
                                   thisatt->attlen,
                                   ctx->tuphdr->t_hoff + ctx->offset,
                                   ctx->lp_len));
        return false;
    }

    /* Skip null values */
    if (infomask & HEAP_HASNULL && att_isnull(ctx->attnum, ctx->tuphdr->t_bits))
        return true;

    /* Skip non-varlena values, but update offset first */
    if (thisatt->attlen != -1)
    {
        ctx->offset = att_align_nominal(ctx->offset, thisatt->attalign);
        ctx->offset = att_addlength_pointer(ctx->offset, thisatt->attlen,
                                            tp + ctx->offset);
        if (ctx->tuphdr->t_hoff + ctx->offset > ctx->lp_len)
        {
            report_corruption(ctx,
                              psprintf("attribute %u with length %u ends at offset %u beyond total tuple length %u",
                                       ctx->attnum,
                                       thisatt->attlen,
                                       ctx->tuphdr->t_hoff + ctx->offset,
                                       ctx->lp_len));
            return false;
        }
        return true;
    }

    /* Ok, we're looking at a varlena attribute. */
    ctx->offset = att_align_pointer(ctx->offset, thisatt->attalign, -1,
                                    tp + ctx->offset);

    /* Get the (possibly corrupt) varlena datum */
    attdatum = fetchatt(thisatt, tp + ctx->offset);

    /*
     * We have the datum, but we cannot decode it carelessly, as it may still
     * be corrupt.
     */

    /*
     * Check that VARTAG_SIZE won't hit a TrapMacro on a corrupt va_tag before
     * risking a call into att_addlength_pointer
     */
    if (VARATT_IS_EXTERNAL(tp + ctx->offset))
    {
        uint8       va_tag = VARTAG_EXTERNAL(tp + ctx->offset);

        if (va_tag != VARTAG_ONDISK)
        {
            report_corruption(ctx,
                              psprintf("toasted attribute %u has unexpected TOAST tag %u",
                                       ctx->attnum,
                                       va_tag));
            /* We can't know where the next attribute begins */
            return false;
        }
    }

    /* Ok, should be safe now */
    ctx->offset = att_addlength_pointer(ctx->offset, thisatt->attlen,
                                        tp + ctx->offset);

    if (ctx->tuphdr->t_hoff + ctx->offset > ctx->lp_len)
    {
        report_corruption(ctx,
                          psprintf("attribute %u with length %u ends at offset %u beyond total tuple length %u",
                                   ctx->attnum,
                                   thisatt->attlen,
                                   ctx->tuphdr->t_hoff + ctx->offset,
                                   ctx->lp_len));

        return false;
    }

    /*
     * heap_deform_tuple would be done with this attribute at this point,
     * having stored it in values[], and would continue to the next attribute.
     * We go further, because we need to check if the toast datum is corrupt.
     */

    attr = (struct varlena *) DatumGetPointer(attdatum);

    /*
     * Now we follow the logic of detoast_external_attr(), with the same
     * caveats about being paranoid about corruption.
     */

    /* Skip values that are not external */
    if (!VARATT_IS_EXTERNAL(attr))
        return true;

    /* It is external, and we're looking at a page on disk */

    /* The tuple header better claim to contain toasted values */
    if (!(infomask & HEAP_HASEXTERNAL))
    {
        report_corruption(ctx,
                          psprintf("attribute %u is external but tuple header flag HEAP_HASEXTERNAL not set",
                                   ctx->attnum));
        return true;
    }

    /* The relation better have a toast table */
    if (!ctx->rel->rd_rel->reltoastrelid)
    {
        report_corruption(ctx,
                          psprintf("attribute %u is external but relation has no toast relation",
                                   ctx->attnum));
        return true;
    }

    /* If we were told to skip toast checking, then we're done. */
    if (ctx->toast_rel == NULL)
        return true;

    /*
     * Must copy attr into toast_pointer for alignment considerations
     */
    VARATT_EXTERNAL_GET_POINTER(toast_pointer, attr);

    ctx->attrsize = toast_pointer.va_extsize;
    ctx->endchunk = (ctx->attrsize - 1) / TOAST_MAX_CHUNK_SIZE;
    ctx->totalchunks = ctx->endchunk + 1;

    /*
     * Setup a scan key to find chunks in toast table with matching va_valueid
     */
    ScanKeyInit(&toastkey,
                (AttrNumber) 1,
                BTEqualStrategyNumber, F_OIDEQ,
                ObjectIdGetDatum(toast_pointer.va_valueid));

    /*
     * Check if any chunks for this toasted object exist in the toast table,
     * accessible via the index.
     */
    init_toast_snapshot(&SnapshotToast);
    toastscan = systable_beginscan_ordered(ctx->toast_rel,
                                           ctx->valid_toast_index,
                                           &SnapshotToast, 1,
                                           &toastkey);
    ctx->chunkno = 0;
    found_toasttup = false;
    while ((toasttup =
            systable_getnext_ordered(toastscan,
                                     ForwardScanDirection)) != NULL)
    {
        found_toasttup = true;
        check_toast_tuple(toasttup, ctx);
        ctx->chunkno++;
    }
    if (ctx->chunkno != (ctx->endchunk + 1))
        report_corruption(ctx,
                          psprintf("final toast chunk number %u differs from expected value %u",
                                   ctx->chunkno, (ctx->endchunk + 1)));
    if (!found_toasttup)
        report_corruption(ctx,
                          psprintf("toasted value for attribute %u missing from toast table",
                                   ctx->attnum));
    systable_endscan_ordered(toastscan);

    return true;
}

check_tuple_header_and_visibilty()

static bool check_tuple_header_and_visibilty ( HeapTupleHeader  tuphdr, HeapCheckContext *  ctx  )

static

Definition at line 598 of file verify_heapam.c.

References BITMAPLEN, EpochFromFullTransactionId, get_xid_status(), HEAP_HASNULL, HEAP_MOVED_IN, HEAP_MOVED_OFF, HEAP_XMAX_COMMITTED, HEAP_XMAX_INVALID, HEAP_XMAX_IS_LOCKED_ONLY, HEAP_XMAX_IS_MULTI, HeapTupleGetUpdateXid(), HeapTupleHeaderGetRawXmin, HeapTupleHeaderGetXvac, HeapTupleHeaderXminCommitted, HeapTupleHeaderXminInvalid, HeapCheckContext::lp_len, MAXALIGN, HeapCheckContext::natts, HeapCheckContext::next_fxid, HeapCheckContext::oldest_fxid, psprintf(), pstrdup(), HeapCheckContext::relfrozenfxid, report_corruption(), SizeofHeapTupleHeader, status(), HeapTupleHeaderData::t_hoff, HeapTupleHeaderData::t_infomask, HeapCheckContext::tuphdr, XID_ABORTED, XID_BOUNDS_OK, XID_COMMITTED, XID_IN_FUTURE, XID_IN_PROGRESS, XID_INVALID, XID_PRECEDES_CLUSTERMIN, XID_PRECEDES_RELMIN, and XidFromFullTransactionId.

Referenced by check_tuple().

{
    uint16      infomask = tuphdr->t_infomask;
    bool        header_garbled = false;
    unsigned    expected_hoff;

    if (ctx->tuphdr->t_hoff > ctx->lp_len)
    {
        report_corruption(ctx,
                          psprintf("data begins at offset %u beyond the tuple length %u",
                                   ctx->tuphdr->t_hoff, ctx->lp_len));
        header_garbled = true;
    }

    if ((ctx->tuphdr->t_infomask & HEAP_XMAX_COMMITTED) &&
        (ctx->tuphdr->t_infomask & HEAP_XMAX_IS_MULTI))
    {
        report_corruption(ctx,
                          pstrdup("multixact should not be marked committed"));

        /*
         * This condition is clearly wrong, but we do not consider the header
         * garbled, because we don't rely on this property for determining if
         * the tuple is visible or for interpreting other relevant header
         * fields.
         */
    }

    if (infomask & HEAP_HASNULL)
        expected_hoff = MAXALIGN(SizeofHeapTupleHeader + BITMAPLEN(ctx->natts));
    else
        expected_hoff = MAXALIGN(SizeofHeapTupleHeader);
    if (ctx->tuphdr->t_hoff != expected_hoff)
    {
        if ((infomask & HEAP_HASNULL) && ctx->natts == 1)
            report_corruption(ctx,
                              psprintf("tuple data should begin at byte %u, but actually begins at byte %u (1 attribute, has nulls)",
                                       expected_hoff, ctx->tuphdr->t_hoff));
        else if ((infomask & HEAP_HASNULL))
            report_corruption(ctx,
                              psprintf("tuple data should begin at byte %u, but actually begins at byte %u (%u attributes, has nulls)",
                                       expected_hoff, ctx->tuphdr->t_hoff, ctx->natts));
        else if (ctx->natts == 1)
            report_corruption(ctx,
                              psprintf("tuple data should begin at byte %u, but actually begins at byte %u (1 attribute, no nulls)",
                                       expected_hoff, ctx->tuphdr->t_hoff));
        else
            report_corruption(ctx,
                              psprintf("tuple data should begin at byte %u, but actually begins at byte %u (%u attributes, no nulls)",
                                       expected_hoff, ctx->tuphdr->t_hoff, ctx->natts));
        header_garbled = true;
    }

    if (header_garbled)
        return false;           /* checking of this tuple should not continue */

    /*
     * Ok, we can examine the header for tuple visibility purposes, though we
     * still need to be careful about a few remaining types of header
     * corruption.  This logic roughly follows that of
     * HeapTupleSatisfiesVacuum.  Where possible the comments indicate which
     * HTSV_Result we think that function might return for this tuple.
     */
    if (!HeapTupleHeaderXminCommitted(tuphdr))
    {
        TransactionId raw_xmin = HeapTupleHeaderGetRawXmin(tuphdr);

        if (HeapTupleHeaderXminInvalid(tuphdr))
            return false;       /* HEAPTUPLE_DEAD */
        /* Used by pre-9.0 binary upgrades */
        else if (infomask & HEAP_MOVED_OFF ||
                 infomask & HEAP_MOVED_IN)
        {
            XidCommitStatus status;
            TransactionId xvac = HeapTupleHeaderGetXvac(tuphdr);

            switch (get_xid_status(xvac, ctx, &status))
            {
                case XID_INVALID:
                    report_corruption(ctx,
                                      pstrdup("old-style VACUUM FULL transaction ID is invalid"));
                    return false;   /* corrupt */
                case XID_IN_FUTURE:
                    report_corruption(ctx,
                                      psprintf("old-style VACUUM FULL transaction ID %u equals or exceeds next valid transaction ID %u:%u",
                                               xvac,
                                               EpochFromFullTransactionId(ctx->next_fxid),
                                               XidFromFullTransactionId(ctx->next_fxid)));
                    return false;   /* corrupt */
                case XID_PRECEDES_RELMIN:
                    report_corruption(ctx,
                                      psprintf("old-style VACUUM FULL transaction ID %u precedes relation freeze threshold %u:%u",
                                               xvac,
                                               EpochFromFullTransactionId(ctx->relfrozenfxid),
                                               XidFromFullTransactionId(ctx->relfrozenfxid)));
                    return false;   /* corrupt */
                    break;
                case XID_PRECEDES_CLUSTERMIN:
                    report_corruption(ctx,
                                      psprintf("old-style VACUUM FULL transaction ID %u precedes oldest valid transaction ID %u:%u",
                                               xvac,
                                               EpochFromFullTransactionId(ctx->oldest_fxid),
                                               XidFromFullTransactionId(ctx->oldest_fxid)));
                    return false;   /* corrupt */
                    break;
                case XID_BOUNDS_OK:
                    switch (status)
                    {
                        case XID_IN_PROGRESS:
                            return true;    /* HEAPTUPLE_DELETE_IN_PROGRESS */
                        case XID_COMMITTED:
                        case XID_ABORTED:
                            return false;   /* HEAPTUPLE_DEAD */
                    }
            }
        }
        else
        {
            XidCommitStatus status;

            switch (get_xid_status(raw_xmin, ctx, &status))
            {
                case XID_INVALID:
                    report_corruption(ctx,
                                      pstrdup("raw xmin is invalid"));
                    return false;
                case XID_IN_FUTURE:
                    report_corruption(ctx,
                                      psprintf("raw xmin %u equals or exceeds next valid transaction ID %u:%u",
                                               raw_xmin,
                                               EpochFromFullTransactionId(ctx->next_fxid),
                                               XidFromFullTransactionId(ctx->next_fxid)));
                    return false;   /* corrupt */
                case XID_PRECEDES_RELMIN:
                    report_corruption(ctx,
                                      psprintf("raw xmin %u precedes relation freeze threshold %u:%u",
                                               raw_xmin,
                                               EpochFromFullTransactionId(ctx->relfrozenfxid),
                                               XidFromFullTransactionId(ctx->relfrozenfxid)));
                    return false;   /* corrupt */
                case XID_PRECEDES_CLUSTERMIN:
                    report_corruption(ctx,
                                      psprintf("raw xmin %u precedes oldest valid transaction ID %u:%u",
                                               raw_xmin,
                                               EpochFromFullTransactionId(ctx->oldest_fxid),
                                               XidFromFullTransactionId(ctx->oldest_fxid)));
                    return false;   /* corrupt */
                case XID_BOUNDS_OK:
                    switch (status)
                    {
                        case XID_COMMITTED:
                            break;
                        case XID_IN_PROGRESS:
                            return true;    /* insert or delete in progress */
                        case XID_ABORTED:
                            return false;   /* HEAPTUPLE_DEAD */
                    }
            }
        }
    }

    if (!(infomask & HEAP_XMAX_INVALID) && !HEAP_XMAX_IS_LOCKED_ONLY(infomask))
    {
        if (infomask & HEAP_XMAX_IS_MULTI)
        {
            XidCommitStatus status;
            TransactionId xmax = HeapTupleGetUpdateXid(tuphdr);

            switch (get_xid_status(xmax, ctx, &status))
            {
                    /* not LOCKED_ONLY, so it has to have an xmax */
                case XID_INVALID:
                    report_corruption(ctx,
                                      pstrdup("xmax is invalid"));
                    return false;   /* corrupt */
                case XID_IN_FUTURE:
                    report_corruption(ctx,
                                      psprintf("xmax %u equals or exceeds next valid transaction ID %u:%u",
                                               xmax,
                                               EpochFromFullTransactionId(ctx->next_fxid),
                                               XidFromFullTransactionId(ctx->next_fxid)));
                    return false;   /* corrupt */
                case XID_PRECEDES_RELMIN:
                    report_corruption(ctx,
                                      psprintf("xmax %u precedes relation freeze threshold %u:%u",
                                               xmax,
                                               EpochFromFullTransactionId(ctx->relfrozenfxid),
                                               XidFromFullTransactionId(ctx->relfrozenfxid)));
                    return false;   /* corrupt */
                case XID_PRECEDES_CLUSTERMIN:
                    report_corruption(ctx,
                                      psprintf("xmax %u precedes oldest valid transaction ID %u:%u",
                                               xmax,
                                               EpochFromFullTransactionId(ctx->oldest_fxid),
                                               XidFromFullTransactionId(ctx->oldest_fxid)));
                    return false;   /* corrupt */
                case XID_BOUNDS_OK:
                    switch (status)
                    {
                        case XID_IN_PROGRESS:
                            return true;    /* HEAPTUPLE_DELETE_IN_PROGRESS */
                        case XID_COMMITTED:
                        case XID_ABORTED:
                            return false;   /* HEAPTUPLE_RECENTLY_DEAD or
                                             * HEAPTUPLE_DEAD */
                    }
            }

            /* Ok, the tuple is live */
        }
        else if (!(infomask & HEAP_XMAX_COMMITTED))
            return true;        /* HEAPTUPLE_DELETE_IN_PROGRESS or
                                 * HEAPTUPLE_LIVE */
        else
            return false;       /* HEAPTUPLE_RECENTLY_DEAD or HEAPTUPLE_DEAD */
    }
    return true;                /* not dead */
}

FullTransactionIdFromXidAndCtx()

static FullTransactionId FullTransactionIdFromXidAndCtx ( TransactionId  xid, const HeapCheckContext *  ctx  )

static

Definition at line 1288 of file verify_heapam.c.

References epoch, EpochFromFullTransactionId, FullTransactionIdFromEpochAndXid(), HeapCheckContext::next_fxid, HeapCheckContext::next_xid, and TransactionIdIsNormal.

Referenced by get_xid_status(), update_cached_xid_range(), and verify_heapam().

{
    uint32      epoch;

    if (!TransactionIdIsNormal(xid))
        return FullTransactionIdFromEpochAndXid(0, xid);
    epoch = EpochFromFullTransactionId(ctx->next_fxid);
    if (xid > ctx->next_xid)
        epoch--;
    return FullTransactionIdFromEpochAndXid(epoch, xid);
}

fxid_in_cached_range()

static bool fxid_in_cached_range ( FullTransactionId  fxid, const HeapCheckContext *  ctx  )

inlinestatic

Definition at line 1331 of file verify_heapam.c.

References FullTransactionIdPrecedes, FullTransactionIdPrecedesOrEquals, HeapCheckContext::next_fxid, and HeapCheckContext::oldest_fxid.

Referenced by get_xid_status().

{
    return (FullTransactionIdPrecedesOrEquals(ctx->oldest_fxid, fxid) &&
            FullTransactionIdPrecedes(fxid, ctx->next_fxid));
}

get_xid_status()

static XidBoundsViolation get_xid_status ( TransactionId  xid, HeapCheckContext *  ctx, XidCommitStatus *  status  )

static

Definition at line 1396 of file verify_heapam.c.

References BootstrapTransactionId, HeapCheckContext::cached_status, HeapCheckContext::cached_xid, FrozenTransactionId, FullTransactionIdFromXidAndCtx(), FullTransactionIdPrecedes, FullTransactionIdPrecedesOrEquals, fxid_in_cached_range(), LW_SHARED, LWLockAcquire(), LWLockRelease(), HeapCheckContext::next_fxid, HeapCheckContext::oldest_fxid, VariableCacheData::oldestClogXid, HeapCheckContext::relfrozenfxid, ShmemVariableCache, status(), TransactionIdDidAbort(), TransactionIdDidCommit(), TransactionIdIsCurrentTransactionId(), TransactionIdIsValid, update_cached_xid_range(), XID_ABORTED, XID_BOUNDS_OK, XID_COMMITTED, XID_IN_FUTURE, XID_IN_PROGRESS, XID_INVALID, XID_PRECEDES_CLUSTERMIN, and XID_PRECEDES_RELMIN.

Referenced by check_tuple(), and check_tuple_header_and_visibilty().

{
    FullTransactionId fxid;
    FullTransactionId clog_horizon;

    /* Quick check for special xids */
    if (!TransactionIdIsValid(xid))
        return XID_INVALID;
    else if (xid == BootstrapTransactionId || xid == FrozenTransactionId)
    {
        if (status != NULL)
            *status = XID_COMMITTED;
        return XID_BOUNDS_OK;
    }

    /* Check if the xid is within bounds */
    fxid = FullTransactionIdFromXidAndCtx(xid, ctx);
    if (!fxid_in_cached_range(fxid, ctx))
    {
        /*
         * We may have been checking against stale values.  Update the cached
         * range to be sure, and since we relied on the cached range when we
         * performed the full xid conversion, reconvert.
         */
        update_cached_xid_range(ctx);
        fxid = FullTransactionIdFromXidAndCtx(xid, ctx);
    }

    if (FullTransactionIdPrecedesOrEquals(ctx->next_fxid, fxid))
        return XID_IN_FUTURE;
    if (FullTransactionIdPrecedes(fxid, ctx->oldest_fxid))
        return XID_PRECEDES_CLUSTERMIN;
    if (FullTransactionIdPrecedes(fxid, ctx->relfrozenfxid))
        return XID_PRECEDES_RELMIN;

    /* Early return if the caller does not request clog checking */
    if (status == NULL)
        return XID_BOUNDS_OK;

    /* Early return if we just checked this xid in a prior call */
    if (xid == ctx->cached_xid)
    {
        *status = ctx->cached_status;
        return XID_BOUNDS_OK;
    }

    *status = XID_COMMITTED;
    LWLockAcquire(XactTruncationLock, LW_SHARED);
    clog_horizon =
        FullTransactionIdFromXidAndCtx(ShmemVariableCache->oldestClogXid,
                                       ctx);
    if (FullTransactionIdPrecedesOrEquals(clog_horizon, fxid))
    {
        if (TransactionIdIsCurrentTransactionId(xid))
            *status = XID_IN_PROGRESS;
        else if (TransactionIdDidCommit(xid))
            *status = XID_COMMITTED;
        else if (TransactionIdDidAbort(xid))
            *status = XID_ABORTED;
        else
            *status = XID_IN_PROGRESS;
    }
    LWLockRelease(XactTruncationLock);
    ctx->cached_xid = xid;
    ctx->cached_status = *status;
    return XID_BOUNDS_OK;
}

PG_FUNCTION_INFO_V1()

PG_FUNCTION_INFO_V1

(

verify_heapam

)

report_corruption()

static void report_corruption ( HeapCheckContext *  ctx, char *  msg  )

static

Definition at line 508 of file verify_heapam.c.

References HeapCheckContext::attnum, HeapCheckContext::blkno, CStringGetTextDatum, heap_form_tuple(), HEAPCHECK_RELATION_COLS, Int32GetDatum, Int64GetDatum(), HeapCheckContext::is_corrupt, MemSet, HeapCheckContext::offnum, pfree(), HeapCheckContext::tupdesc, tuplestore_puttuple(), HeapCheckContext::tupstore, and values.

Referenced by check_toast_tuple(), check_tuple(), check_tuple_attribute(), check_tuple_header_and_visibilty(), and verify_heapam().

{
    Datum       values[HEAPCHECK_RELATION_COLS];
    bool        nulls[HEAPCHECK_RELATION_COLS];
    HeapTuple   tuple;

    MemSet(values, 0, sizeof(values));
    MemSet(nulls, 0, sizeof(nulls));
    values[0] = Int64GetDatum(ctx->blkno);
    values[1] = Int32GetDatum(ctx->offnum);
    values[2] = Int32GetDatum(ctx->attnum);
    nulls[2] = (ctx->attnum < 0);
    values[3] = CStringGetTextDatum(msg);

    /*
     * In principle, there is nothing to prevent a scan over a large, highly
     * corrupted table from using work_mem worth of memory building up the
     * tuplestore.  That's ok, but if we also leak the msg argument memory
     * until the end of the query, we could exceed work_mem by more than a
     * trivial amount.  Therefore, free the msg argument each time we are
     * called rather than waiting for our current memory context to be freed.
     */
    pfree(msg);

    tuple = heap_form_tuple(ctx->tupdesc, values, nulls);
    tuplestore_puttuple(ctx->tupstore, tuple);
    ctx->is_corrupt = true;
}

sanity_check_relation()

static void sanity_check_relation ( Relation  rel )

static

Definition at line 485 of file verify_heapam.c.

References ereport, errcode(), errmsg(), ERROR, RelationData::rd_rel, and RelationGetRelationName.

Referenced by verify_heapam().

{
    if (rel->rd_rel->relkind != RELKIND_RELATION &&
        rel->rd_rel->relkind != RELKIND_MATVIEW &&
        rel->rd_rel->relkind != RELKIND_TOASTVALUE)
        ereport(ERROR,
                (errcode(ERRCODE_WRONG_OBJECT_TYPE),
                 errmsg("\"%s\" is not a table, materialized view, or TOAST table",
                        RelationGetRelationName(rel))));
    if (rel->rd_rel->relam != HEAP_TABLE_AM_OID)
        ereport(ERROR,
                (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
                 errmsg("only heap AM is supported")));
}

update_cached_mxid_range()

static void update_cached_mxid_range ( HeapCheckContext *  ctx )

static

Definition at line 1321 of file verify_heapam.c.

References HeapCheckContext::next_mxact, HeapCheckContext::oldest_mxact, and ReadMultiXactIdRange().

Referenced by check_mxid_valid_in_rel(), and verify_heapam().

{
    ReadMultiXactIdRange(&ctx->oldest_mxact, &ctx->next_mxact);
}

update_cached_xid_range()

static void update_cached_xid_range ( HeapCheckContext *  ctx )

static

Definition at line 1304 of file verify_heapam.c.

References FullTransactionIdFromXidAndCtx(), LW_SHARED, LWLockAcquire(), LWLockRelease(), HeapCheckContext::next_fxid, HeapCheckContext::next_xid, VariableCacheData::nextXid, HeapCheckContext::oldest_fxid, HeapCheckContext::oldest_xid, VariableCacheData::oldestXid, ShmemVariableCache, and XidFromFullTransactionId.

Referenced by get_xid_status(), and verify_heapam().

{
    /* Make cached copies */
    LWLockAcquire(XidGenLock, LW_SHARED);
    ctx->next_fxid = ShmemVariableCache->nextXid;
    ctx->oldest_xid = ShmemVariableCache->oldestXid;
    LWLockRelease(XidGenLock);

    /* And compute alternate versions of the same */
    ctx->oldest_fxid = FullTransactionIdFromXidAndCtx(ctx->oldest_xid, ctx);
    ctx->next_xid = XidFromFullTransactionId(ctx->next_fxid);
}

verify_heapam()

Datum verify_heapam

(

PG_FUNCTION_ARGS

)

Definition at line 186 of file verify_heapam.c.

References AccessShareLock, ReturnSetInfo::allowedModes, BAS_BULKREAD, BUFFER_LOCK_SHARE, BufferGetPage, check_tuple(), ReturnSetInfo::econtext, ExprContext::ecxt_per_query_memory, ereport, errcode(), errhint(), errmsg(), ERROR, fb(), FirstOffsetNumber, FullTransactionIdFromXidAndCtx(), GetAccessStrategy(), HeapTupleHeaderGetNatts, InvalidBuffer, InvalidTransactionId, IsA, ItemIdGetLength, ItemIdGetOffset, ItemIdGetRedirect, ItemIdIsDead, ItemIdIsRedirected, ItemIdIsUsed, LockBuffer(), MAIN_FORKNUM, MAXALIGN, MemoryContextSwitchTo(), HeapCheckContext::offset, OffsetNumberNext, PageGetItem, PageGetItemId, PageGetMaxOffsetNumber, PG_ARGISNULL, PG_GETARG_BOOL, PG_GETARG_INT64, PG_GETARG_OID, PG_GETARG_TEXT_PP, PG_RETURN_NULL, pg_strcasecmp(), psprintf(), RBM_NORMAL, ReadBufferExtended(), relation_close(), relation_open(), RelationGetNumberOfBlocks, ReleaseBuffer(), report_corruption(), ReturnSetInfo::returnMode, sanity_check_relation(), ReturnSetInfo::setDesc, ReturnSetInfo::setResult, SFRM_Materialize, SFRM_Materialize_Random, SizeofHeapTupleHeader, skip, SKIP_PAGES_ALL_FROZEN, SKIP_PAGES_ALL_VISIBLE, SKIP_PAGES_NONE, table_close(), table_open(), text_to_cstring(), toast_close_indexes(), toast_open_indexes(), TransactionIdIsNormal, tuplestore_begin_heap(), UnlockReleaseBuffer(), update_cached_mxid_range(), update_cached_xid_range(), verify_heapam_tupdesc(), VISIBILITYMAP_ALL_FROZEN, VISIBILITYMAP_ALL_VISIBLE, visibilitymap_get_status(), and work_mem.

{
    ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo;
    MemoryContext old_context;
    bool        random_access;
    HeapCheckContext ctx;
    Buffer      vmbuffer = InvalidBuffer;
    Oid         relid;
    bool        on_error_stop;
    bool        check_toast;
    SkipPages   skip_option = SKIP_PAGES_NONE;
    BlockNumber first_block;
    BlockNumber last_block;
    BlockNumber nblocks;
    const char *skip;

    /* Check to see if caller supports us returning a tuplestore */
    if (rsinfo == NULL || !IsA(rsinfo, ReturnSetInfo))
        ereport(ERROR,
                (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
                 errmsg("set-valued function called in context that cannot accept a set")));
    if (!(rsinfo->allowedModes & SFRM_Materialize))
        ereport(ERROR,
                (errcode(ERRCODE_SYNTAX_ERROR),
                 errmsg("materialize mode required, but it is not allowed in this context")));

    /* Check supplied arguments */
    if (PG_ARGISNULL(0))
        ereport(ERROR,
                (errcode(ERRCODE_INVALID_PARAMETER_VALUE),
                 errmsg("relation cannot be null")));
    relid = PG_GETARG_OID(0);

    if (PG_ARGISNULL(1))
        ereport(ERROR,
                (errcode(ERRCODE_INVALID_PARAMETER_VALUE),
                 errmsg("on_error_stop cannot be null")));
    on_error_stop = PG_GETARG_BOOL(1);

    if (PG_ARGISNULL(2))
        ereport(ERROR,
                (errcode(ERRCODE_INVALID_PARAMETER_VALUE),
                 errmsg("check_toast cannot be null")));
    check_toast = PG_GETARG_BOOL(2);

    if (PG_ARGISNULL(3))
        ereport(ERROR,
                (errcode(ERRCODE_INVALID_PARAMETER_VALUE),
                 errmsg("skip cannot be null")));
    skip = text_to_cstring(PG_GETARG_TEXT_PP(3));
    if (pg_strcasecmp(skip, "all-visible") == 0)
        skip_option = SKIP_PAGES_ALL_VISIBLE;
    else if (pg_strcasecmp(skip, "all-frozen") == 0)
        skip_option = SKIP_PAGES_ALL_FROZEN;
    else if (pg_strcasecmp(skip, "none") == 0)
        skip_option = SKIP_PAGES_NONE;
    else
        ereport(ERROR,
                (errcode(ERRCODE_INVALID_PARAMETER_VALUE),
                 errmsg("invalid skip option"),
                 errhint("Valid skip options are \"all-visible\", \"all-frozen\", and \"none\".")));

    memset(&ctx, 0, sizeof(HeapCheckContext));
    ctx.cached_xid = InvalidTransactionId;

    /*
     * If we report corruption when not examining some individual attribute,
     * we need attnum to be reported as NULL.  Set that up before any
     * corruption reporting might happen.
     */
    ctx.attnum = -1;

    /* The tupdesc and tuplestore must be created in ecxt_per_query_memory */
    old_context = MemoryContextSwitchTo(rsinfo->econtext->ecxt_per_query_memory);
    random_access = (rsinfo->allowedModes & SFRM_Materialize_Random) != 0;
    ctx.tupdesc = verify_heapam_tupdesc();
    ctx.tupstore = tuplestore_begin_heap(random_access, false, work_mem);
    rsinfo->returnMode = SFRM_Materialize;
    rsinfo->setResult = ctx.tupstore;
    rsinfo->setDesc = ctx.tupdesc;
    MemoryContextSwitchTo(old_context);

    /* Open relation, check relkind and access method, and check privileges */
    ctx.rel = relation_open(relid, AccessShareLock);
    sanity_check_relation(ctx.rel);

    /* Early exit if the relation is empty */
    nblocks = RelationGetNumberOfBlocks(ctx.rel);
    if (!nblocks)
    {
        relation_close(ctx.rel, AccessShareLock);
        PG_RETURN_NULL();
    }

    ctx.bstrategy = GetAccessStrategy(BAS_BULKREAD);
    ctx.buffer = InvalidBuffer;
    ctx.page = NULL;

    /* Validate block numbers, or handle nulls. */
    if (PG_ARGISNULL(4))
        first_block = 0;
    else
    {
        int64       fb = PG_GETARG_INT64(4);

        if (fb < 0 || fb >= nblocks)
            ereport(ERROR,
                    (errcode(ERRCODE_INVALID_PARAMETER_VALUE),
                     errmsg("starting block number must be between 0 and %u",
                            nblocks - 1)));
        first_block = (BlockNumber) fb;
    }
    if (PG_ARGISNULL(5))
        last_block = nblocks - 1;
    else
    {
        int64       lb = PG_GETARG_INT64(5);

        if (lb < 0 || lb >= nblocks)
            ereport(ERROR,
                    (errcode(ERRCODE_INVALID_PARAMETER_VALUE),
                     errmsg("ending block number must be between 0 and %u",
                            nblocks - 1)));
        last_block = (BlockNumber) lb;
    }

    /* Optionally open the toast relation, if any. */
    if (ctx.rel->rd_rel->reltoastrelid && check_toast)
    {
        int         offset;

        /* Main relation has associated toast relation */
        ctx.toast_rel = table_open(ctx.rel->rd_rel->reltoastrelid,
                                   AccessShareLock);
        offset = toast_open_indexes(ctx.toast_rel,
                                    AccessShareLock,
                                    &(ctx.toast_indexes),
                                    &(ctx.num_toast_indexes));
        ctx.valid_toast_index = ctx.toast_indexes[offset];
    }
    else
    {
        /*
         * Main relation has no associated toast relation, or we're
         * intentionally skipping it.
         */
        ctx.toast_rel = NULL;
        ctx.toast_indexes = NULL;
        ctx.num_toast_indexes = 0;
    }

    update_cached_xid_range(&ctx);
    update_cached_mxid_range(&ctx);
    ctx.relfrozenxid = ctx.rel->rd_rel->relfrozenxid;
    ctx.relfrozenfxid = FullTransactionIdFromXidAndCtx(ctx.relfrozenxid, &ctx);
    ctx.relminmxid = ctx.rel->rd_rel->relminmxid;

    if (TransactionIdIsNormal(ctx.relfrozenxid))
        ctx.oldest_xid = ctx.relfrozenxid;

    for (ctx.blkno = first_block; ctx.blkno <= last_block; ctx.blkno++)
    {
        OffsetNumber maxoff;

        /* Optionally skip over all-frozen or all-visible blocks */
        if (skip_option != SKIP_PAGES_NONE)
        {
            int32       mapbits;

            mapbits = (int32) visibilitymap_get_status(ctx.rel, ctx.blkno,
                                                       &vmbuffer);
            if (skip_option == SKIP_PAGES_ALL_FROZEN)
            {
                if ((mapbits & VISIBILITYMAP_ALL_FROZEN) != 0)
                    continue;
            }

            if (skip_option == SKIP_PAGES_ALL_VISIBLE)
            {
                if ((mapbits & VISIBILITYMAP_ALL_VISIBLE) != 0)
                    continue;
            }
        }

        /* Read and lock the next page. */
        ctx.buffer = ReadBufferExtended(ctx.rel, MAIN_FORKNUM, ctx.blkno,
                                        RBM_NORMAL, ctx.bstrategy);
        LockBuffer(ctx.buffer, BUFFER_LOCK_SHARE);
        ctx.page = BufferGetPage(ctx.buffer);

        /* Perform tuple checks */
        maxoff = PageGetMaxOffsetNumber(ctx.page);
        for (ctx.offnum = FirstOffsetNumber; ctx.offnum <= maxoff;
             ctx.offnum = OffsetNumberNext(ctx.offnum))
        {
            ctx.itemid = PageGetItemId(ctx.page, ctx.offnum);

            /* Skip over unused/dead line pointers */
            if (!ItemIdIsUsed(ctx.itemid) || ItemIdIsDead(ctx.itemid))
                continue;

            /*
             * If this line pointer has been redirected, check that it
             * redirects to a valid offset within the line pointer array
             */
            if (ItemIdIsRedirected(ctx.itemid))
            {
                OffsetNumber rdoffnum = ItemIdGetRedirect(ctx.itemid);
                ItemId      rditem;

                if (rdoffnum < FirstOffsetNumber)
                {
                    report_corruption(&ctx,
                                      psprintf("line pointer redirection to item at offset %u precedes minimum offset %u",
                                               (unsigned) rdoffnum,
                                               (unsigned) FirstOffsetNumber));
                    continue;
                }
                if (rdoffnum > maxoff)
                {
                    report_corruption(&ctx,
                                      psprintf("line pointer redirection to item at offset %u exceeds maximum offset %u",
                                               (unsigned) rdoffnum,
                                               (unsigned) maxoff));
                    continue;
                }
                rditem = PageGetItemId(ctx.page, rdoffnum);
                if (!ItemIdIsUsed(rditem))
                    report_corruption(&ctx,
                                      psprintf("line pointer redirection to unused item at offset %u",
                                               (unsigned) rdoffnum));
                continue;
            }

            /* Sanity-check the line pointer's offset and length values */
            ctx.lp_len = ItemIdGetLength(ctx.itemid);
            ctx.lp_off = ItemIdGetOffset(ctx.itemid);

            if (ctx.lp_off != MAXALIGN(ctx.lp_off))
            {
                report_corruption(&ctx,
                                  psprintf("line pointer to page offset %u is not maximally aligned",
                                           ctx.lp_off));
                continue;
            }
            if (ctx.lp_len < MAXALIGN(SizeofHeapTupleHeader))
            {
                report_corruption(&ctx,
                                  psprintf("line pointer length %u is less than the minimum tuple header size %u",
                                           ctx.lp_len,
                                           (unsigned) MAXALIGN(SizeofHeapTupleHeader)));
                continue;
            }
            if (ctx.lp_off + ctx.lp_len > BLCKSZ)
            {
                report_corruption(&ctx,
                                  psprintf("line pointer to page offset %u with length %u ends beyond maximum page offset %u",
                                           ctx.lp_off,
                                           ctx.lp_len,
                                           (unsigned) BLCKSZ));
                continue;
            }

            /* It should be safe to examine the tuple's header, at least */
            ctx.tuphdr = (HeapTupleHeader) PageGetItem(ctx.page, ctx.itemid);
            ctx.natts = HeapTupleHeaderGetNatts(ctx.tuphdr);

            /* Ok, ready to check this next tuple */
            check_tuple(&ctx);
        }

        /* clean up */
        UnlockReleaseBuffer(ctx.buffer);

        if (on_error_stop && ctx.is_corrupt)
            break;
    }

    if (vmbuffer != InvalidBuffer)
        ReleaseBuffer(vmbuffer);

    /* Close the associated toast table and indexes, if any. */
    if (ctx.toast_indexes)
        toast_close_indexes(ctx.toast_indexes, ctx.num_toast_indexes,
                            AccessShareLock);
    if (ctx.toast_rel)
        table_close(ctx.toast_rel, AccessShareLock);

    /* Close the main relation */
    relation_close(ctx.rel, AccessShareLock);

    PG_RETURN_NULL();
}

verify_heapam_tupdesc()

static TupleDesc verify_heapam_tupdesc ( void  )

static

Definition at line 542 of file verify_heapam.c.

References Assert, BlessTupleDesc(), CreateTemplateTupleDesc(), HEAPCHECK_RELATION_COLS, HeapCheckContext::tupdesc, and TupleDescInitEntry().

Referenced by verify_heapam().

{
    TupleDesc   tupdesc;
    AttrNumber  a = 0;

    tupdesc = CreateTemplateTupleDesc(HEAPCHECK_RELATION_COLS);
    TupleDescInitEntry(tupdesc, ++a, "blkno", INT8OID, -1, 0);
    TupleDescInitEntry(tupdesc, ++a, "offnum", INT4OID, -1, 0);
    TupleDescInitEntry(tupdesc, ++a, "attnum", INT4OID, -1, 0);
    TupleDescInitEntry(tupdesc, ++a, "msg", TEXTOID, -1, 0);
    Assert(a == HEAPCHECK_RELATION_COLS);

    return BlessTupleDesc(tupdesc);
}