bool readonly;
/* Also verifying heap has no unindexed tuples? */
bool heapallindexed;
+ /* Also making sure non-pivot tuples can be found by new search? */
+ bool rootdescend;
/* Per-page context */
MemoryContext targetcontext;
/* Buffer access strategy */
PG_FUNCTION_INFO_V1(bt_index_parent_check);
static void bt_index_check_internal(Oid indrelid, bool parentcheck,
- bool heapallindexed);
+ bool heapallindexed, bool rootdescend);
static inline void btree_index_checkable(Relation rel);
static void bt_check_every_level(Relation rel, Relation heaprel,
- bool heapkeyspace, bool readonly, bool heapallindexed);
+ bool heapkeyspace, bool readonly, bool heapallindexed,
+ bool rootdescend);
static BtreeLevel bt_check_level_from_leftmost(BtreeCheckState *state,
BtreeLevel level);
static void bt_target_page_check(BtreeCheckState *state);
bool tupleIsAlive, void *checkstate);
static IndexTuple bt_normalize_tuple(BtreeCheckState *state,
IndexTuple itup);
+static bool bt_rootdescend(BtreeCheckState *state, IndexTuple itup);
static inline bool offset_is_negative_infinity(BTPageOpaque opaque,
OffsetNumber offset);
static inline bool invariant_l_offset(BtreeCheckState *state, BTScanInsert key,
if (PG_NARGS() == 2)
heapallindexed = PG_GETARG_BOOL(1);
- bt_index_check_internal(indrelid, false, heapallindexed);
+ bt_index_check_internal(indrelid, false, heapallindexed, false);
PG_RETURN_VOID();
}
{
Oid indrelid = PG_GETARG_OID(0);
bool heapallindexed = false;
+ bool rootdescend = false;
- if (PG_NARGS() == 2)
+ if (PG_NARGS() >= 2)
heapallindexed = PG_GETARG_BOOL(1);
+ if (PG_NARGS() == 3)
+ rootdescend = PG_GETARG_BOOL(2);
- bt_index_check_internal(indrelid, true, heapallindexed);
+ bt_index_check_internal(indrelid, true, heapallindexed, rootdescend);
PG_RETURN_VOID();
}
* Helper for bt_index_[parent_]check, coordinating the bulk of the work.
*/
static void
-bt_index_check_internal(Oid indrelid, bool parentcheck, bool heapallindexed)
+bt_index_check_internal(Oid indrelid, bool parentcheck, bool heapallindexed,
+ bool rootdescend)
{
Oid heapid;
Relation indrel;
/* Check index, possibly against table it is an index on */
heapkeyspace = _bt_heapkeyspace(indrel);
bt_check_every_level(indrel, heaprel, heapkeyspace, parentcheck,
- heapallindexed);
+ heapallindexed, rootdescend);
/*
* Release locks early. That's ok here because nothing in the called
*/
static void
bt_check_every_level(Relation rel, Relation heaprel, bool heapkeyspace,
- bool readonly, bool heapallindexed)
+ bool readonly, bool heapallindexed, bool rootdescend)
{
BtreeCheckState *state;
Page metapage;
state->heapkeyspace = heapkeyspace;
state->readonly = readonly;
state->heapallindexed = heapallindexed;
+ state->rootdescend = rootdescend;
if (state->heapallindexed)
{
}
}
+ Assert(!state->rootdescend || state->readonly);
+ if (state->rootdescend && !state->heapkeyspace)
+ ereport(ERROR,
+ (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+ errmsg("cannot verify that tuples from index \"%s\" can each be found by an independent index search",
+ RelationGetRelationName(rel)),
+ errhint("Only B-Tree version 4 indexes support rootdescend verification.")));
+
/* Create context for page */
state->targetcontext = AllocSetContextCreate(CurrentMemoryContext,
"amcheck context",
if (offset_is_negative_infinity(topaque, offset))
continue;
+ /*
+ * Readonly callers may optionally verify that non-pivot tuples can
+ * each be found by an independent search that starts from the root
+ */
+ if (state->rootdescend && P_ISLEAF(topaque) &&
+ !bt_rootdescend(state, itup))
+ {
+ char *itid,
+ *htid;
+
+ itid = psprintf("(%u,%u)", state->targetblock, offset);
+ htid = psprintf("(%u,%u)",
+ ItemPointerGetBlockNumber(&(itup->t_tid)),
+ ItemPointerGetOffsetNumber(&(itup->t_tid)));
+
+ ereport(ERROR,
+ (errcode(ERRCODE_INDEX_CORRUPTED),
+ errmsg("could not find tuple using search from root page in index \"%s\"",
+ RelationGetRelationName(state->rel)),
+ errdetail_internal("Index tid=%s points to heap tid=%s page lsn=%X/%X.",
+ itid, htid,
+ (uint32) (state->targetlsn >> 32),
+ (uint32) state->targetlsn)));
+ }
+
/* Build insertion scankey for current page offset */
skey = bt_mkscankey_pivotsearch(state->rel, itup);
* internal pages. In more general terms, a negative infinity item is
* only negative infinity with respect to the subtree that the page is
* at the root of.
+ *
+ * See also: bt_rootdescend(), which can even detect transitive
+ * inconsistencies on cousin leaf pages.
*/
if (offset_is_negative_infinity(copaque, offset))
continue;
return reformed;
}
+/*
+ * Search for itup in index, starting from fast root page. itup must be a
+ * non-pivot tuple. This is only supported with heapkeyspace indexes, since
+ * we rely on having fully unique keys to find a match with only a signle
+ * visit to a leaf page, barring an interrupted page split, where we may have
+ * to move right. (A concurrent page split is impossible because caller must
+ * be readonly caller.)
+ *
+ * This routine can detect very subtle transitive consistency issues across
+ * more than one level of the tree. Leaf pages all have a high key (even the
+ * rightmost page has a conceptual positive infinity high key), but not a low
+ * key. Their downlink in parent is a lower bound, which along with the high
+ * key is almost enough to detect every possible inconsistency. A downlink
+ * separator key value won't always be available from parent, though, because
+ * the first items of internal pages are negative infinity items, truncated
+ * down to zero attributes during internal page splits. While it's true that
+ * bt_downlink_check() and the high key check can detect most imaginable key
+ * space problems, there are remaining problems it won't detect with non-pivot
+ * tuples in cousin leaf pages. Starting a search from the root for every
+ * existing leaf tuple detects small inconsistencies in upper levels of the
+ * tree that cannot be detected any other way. (Besides all this, this is
+ * probably also useful as a direct test of the code used by index scans
+ * themselves.)
+ */
+static bool
+bt_rootdescend(BtreeCheckState *state, IndexTuple itup)
+{
+ BTScanInsert key;
+ BTStack stack;
+ Buffer lbuf;
+ bool exists;
+
+ key = _bt_mkscankey(state->rel, itup);
+ Assert(key->heapkeyspace && key->scantid != NULL);
+
+ /*
+ * Search from root.
+ *
+ * Ideally, we would arrange to only move right within _bt_search() when
+ * an interrupted page split is detected (i.e. when the incomplete split
+ * bit is found to be set), but for now we accept the possibility that
+ * that could conceal an inconsistency.
+ */
+ Assert(state->readonly && state->rootdescend);
+ exists = false;
+ stack = _bt_search(state->rel, key, &lbuf, BT_READ, NULL);
+
+ if (BufferIsValid(lbuf))
+ {
+ BTInsertStateData insertstate;
+ OffsetNumber offnum;
+ Page page;
+
+ insertstate.itup = itup;
+ insertstate.itemsz = MAXALIGN(IndexTupleSize(itup));
+ insertstate.itup_key = key;
+ insertstate.bounds_valid = false;
+ insertstate.buf = lbuf;
+
+ /* Get matching tuple on leaf page */
+ offnum = _bt_binsrch_insert(state->rel, &insertstate);
+ /* Compare first >= matching item on leaf page, if any */
+ page = BufferGetPage(lbuf);
+ if (offnum <= PageGetMaxOffsetNumber(page) &&
+ _bt_compare(state->rel, key, page, offnum) == 0)
+ exists = true;
+ _bt_relbuf(state->rel, lbuf);
+ }
+
+ _bt_freestack(stack);
+ pfree(key);
+
+ return exists;
+}
+
/*
* Is particular offset within page (whose special state is passed by caller)
* the page negative-infinity item?
projects / postgresql.git / commitdiff