[PATCH 1/1] Amcheck for GIN
Heikki Linnakangas <heikki.linnakangas@iki.fi>
From: Heikki Linnakangas <heikki.linnakangas@iki.fi>
To:
Date: 2021-07-20T15:33:04Z
Lists: pgsql-bugs
This is a special version that applies to PostgreSQL v13
changes since last patch version:
- print a lot more INFO messages even when nothing's wrong
- don't stop on error, report as warning
Author: Grigory Kryachko
Discussion: https://www.postgresql.org/message-id/CAF3eApa07-BajjG8%2BRYx-Dr_cq28ZA0GsZmUQrGu5b2ayRhB5A%40mail.gmail.com
---
contrib/amcheck/Makefile | 7 +-
contrib/amcheck/amcheck--1.2--1.2.1.sql | 15 +
contrib/amcheck/amcheck.c | 161 +++++
contrib/amcheck/amcheck.control | 2 +-
contrib/amcheck/amcheck.h | 23 +
contrib/amcheck/expected/check_gin.out | 60 ++
contrib/amcheck/sql/check_gin.sql | 40 ++
contrib/amcheck/verify_gin.c | 822 ++++++++++++++++++++++++
doc/src/sgml/amcheck.sgml | 19 +
9 files changed, 1146 insertions(+), 3 deletions(-)
create mode 100644 contrib/amcheck/amcheck--1.2--1.2.1.sql
create mode 100644 contrib/amcheck/amcheck.c
create mode 100644 contrib/amcheck/amcheck.h
create mode 100644 contrib/amcheck/expected/check_gin.out
create mode 100644 contrib/amcheck/sql/check_gin.sql
create mode 100644 contrib/amcheck/verify_gin.c
diff --git a/contrib/amcheck/Makefile b/contrib/amcheck/Makefile
index a2b1b1036b..a2786e990d 100644
--- a/contrib/amcheck/Makefile
+++ b/contrib/amcheck/Makefile
@@ -3,13 +3,16 @@
MODULE_big = amcheck
OBJS = \
$(WIN32RES) \
+ amcheck.o \
+ verify_gin.o \
verify_nbtree.o
EXTENSION = amcheck
-DATA = amcheck--1.1--1.2.sql amcheck--1.0--1.1.sql amcheck--1.0.sql
+DATA = amcheck--1.1--1.2.sql amcheck--1.0--1.1.sql amcheck--1.0.sql \
+ amcheck--1.2--1.2.1.sql
PGFILEDESC = "amcheck - function for verifying relation integrity"
-REGRESS = check check_btree
+REGRESS = check check_btree check_gin
ifdef USE_PGXS
PG_CONFIG = pg_config
diff --git a/contrib/amcheck/amcheck--1.2--1.2.1.sql b/contrib/amcheck/amcheck--1.2--1.2.1.sql
new file mode 100644
index 0000000000..60d9dd1ab9
--- /dev/null
+++ b/contrib/amcheck/amcheck--1.2--1.2.1.sql
@@ -0,0 +1,15 @@
+/* contrib/amcheck/amcheck--1.3--1.4.sql */
+
+-- complain if script is sourced in psql, rather than via CREATE EXTENSION
+\echo Use "ALTER EXTENSION amcheck UPDATE TO '1.4'" to load this file. \quit
+
+
+--
+-- gin_index_parent_check()
+--
+CREATE FUNCTION gin_index_parent_check(index regclass)
+RETURNS VOID
+AS 'MODULE_PATHNAME', 'gin_index_parent_check'
+LANGUAGE C STRICT;
+
+REVOKE ALL ON FUNCTION gin_index_parent_check(regclass) FROM PUBLIC;
diff --git a/contrib/amcheck/amcheck.c b/contrib/amcheck/amcheck.c
new file mode 100644
index 0000000000..e068b31b43
--- /dev/null
+++ b/contrib/amcheck/amcheck.c
@@ -0,0 +1,161 @@
+/*-------------------------------------------------------------------------
+ *
+ * amcheck.c
+ * Utility functions common to all access methods.
+ *
+ * Copyright (c) 2017-2019, PostgreSQL Global Development Group
+ *
+ * IDENTIFICATION
+ * contrib/amcheck/amcheck.c
+ *
+ *-------------------------------------------------------------------------
+ */
+#include "postgres.h"
+
+#include "access/genam.h"
+#include "access/table.h"
+#include "access/tableam.h"
+#include "amcheck.h"
+#include "catalog/index.h"
+#include "commands/tablecmds.h"
+
+
+/*
+ * Lock acquisition reused across different am types
+ */
+void
+amcheck_lock_relation(Oid indrelid, Relation *indrel,
+ Relation *heaprel, LOCKMODE lockmode)
+{
+ Oid heapid;
+
+ /*
+ * We must lock table before index to avoid deadlocks. However, if the
+ * passed indrelid isn't an index then IndexGetRelation() will fail.
+ * Rather than emitting a not-very-helpful error message, postpone
+ * complaining, expecting that the is-it-an-index test below will fail.
+ *
+ * In hot standby mode this will raise an error when lockmode is
+ * AccessExclusiveLock.
+ */
+ heapid = IndexGetRelation(indrelid, true);
+ if (OidIsValid(heapid))
+ *heaprel = table_open(heapid, lockmode);
+ else
+ *heaprel = NULL;
+
+ /*
+ * Open the target index relations separately (like relation_openrv(), but
+ * with heap relation locked first to prevent deadlocking). In hot
+ * standby mode this will raise an error when lockmode is
+ * AccessExclusiveLock.
+ *
+ * There is no need for the usual indcheckxmin usability horizon test
+ * here, even in the nbtree heapallindexed case, because index undergoing
+ * verification only needs to have entries for a new transaction snapshot.
+ * (If caller is about to do nbtree parentcheck verification, there is no
+ * question about committed or recently dead heap tuples lacking index
+ * entries due to concurrent activity.)
+ */
+ *indrel = index_open(indrelid, lockmode);
+
+ /*
+ * Since we did the IndexGetRelation call above without any lock, it's
+ * barely possible that a race against an index drop/recreation could have
+ * netted us the wrong table.
+ */
+ if (*heaprel == NULL || heapid != IndexGetRelation(indrelid, false))
+ ereport(ERROR,
+ (errcode(ERRCODE_UNDEFINED_TABLE),
+ errmsg("could not open parent table of index %s",
+ RelationGetRelationName(*indrel))));
+}
+
+/*
+ * Unlock index and heap relations early for amcheck_lock_relation() caller.
+ *
+ * This is ok because nothing in the called routines will trigger shared cache
+ * invalidations to be sent, so we can relax the usual pattern of only
+ * releasing locks after commit.
+ */
+void
+amcheck_unlock_relation(Oid indrelid, Relation indrel, Relation heaprel,
+ LOCKMODE lockmode)
+{
+ index_close(indrel, lockmode);
+ if (heaprel)
+ table_close(heaprel, lockmode);
+}
+
+/*
+ * Check if index relation should have a file for its main relation
+ * fork. Verification uses this to skip unlogged indexes when in hot standby
+ * mode, where there is simply nothing to verify.
+ *
+ * NB: Caller should call btree_index_checkable() or gist_index_checkable()
+ * before calling here.
+ */
+bool
+amcheck_index_mainfork_expected(Relation rel)
+{
+ if (rel->rd_rel->relpersistence != RELPERSISTENCE_UNLOGGED ||
+ !RecoveryInProgress())
+ return true;
+
+ ereport(NOTICE,
+ (errcode(ERRCODE_READ_ONLY_SQL_TRANSACTION),
+ errmsg("cannot verify unlogged index \"%s\" during recovery, skipping",
+ RelationGetRelationName(rel))));
+
+ return false;
+}
+
+/*
+ * PageGetItemId() wrapper that validates returned line pointer.
+ *
+ * Buffer page/page item access macros generally trust that line pointers are
+ * not corrupt, which might cause problems for verification itself. For
+ * example, there is no bounds checking in PageGetItem(). Passing it a
+ * corrupt line pointer can cause it to return a tuple/pointer that is unsafe
+ * to dereference.
+ *
+ * Validating line pointers before tuples avoids undefined behavior and
+ * assertion failures with corrupt indexes, making the verification process
+ * more robust and predictable.
+ */
+ItemId
+PageGetItemIdCareful(Relation rel, BlockNumber block, Page page,
+ OffsetNumber offset, size_t opaquesize)
+{
+ ItemId itemid = PageGetItemId(page, offset);
+
+ if (ItemIdGetOffset(itemid) + ItemIdGetLength(itemid) >
+ BLCKSZ - opaquesize)
+ ereport(ERROR,
+ (errcode(ERRCODE_INDEX_CORRUPTED),
+ errmsg("line pointer points past end of tuple space in index \"%s\"",
+ RelationGetRelationName(rel)),
+ errdetail_internal("Index tid=(%u,%u) lp_off=%u, lp_len=%u lp_flags=%u.",
+ block, offset, ItemIdGetOffset(itemid),
+ ItemIdGetLength(itemid),
+ ItemIdGetFlags(itemid))));
+
+ /*
+ * Verify that line pointer isn't LP_REDIRECT or LP_UNUSED, since nbtree and gist
+ * never uses either. Verify that line pointer has storage, too, since
+ * even LP_DEAD items should.
+ */
+// TODO adapt for gin and uncomment
+// if (ItemIdIsRedirected(itemid) || !ItemIdIsUsed(itemid) ||
+// ItemIdGetLength(itemid) == 0)
+// ereport(ERROR,
+// (errcode(ERRCODE_INDEX_CORRUPTED),
+// errmsg("invalid line pointer storage in index \"%s\"",
+// RelationGetRelationName(rel)),
+// errdetail_internal("Index tid=(%u,%u) lp_off=%u, lp_len=%u lp_flags=%u.",
+// block, offset, ItemIdGetOffset(itemid),
+// ItemIdGetLength(itemid),
+// ItemIdGetFlags(itemid))));
+
+ return itemid;
+}
diff --git a/contrib/amcheck/amcheck.control b/contrib/amcheck/amcheck.control
index c6e310046d..70ace506a6 100644
--- a/contrib/amcheck/amcheck.control
+++ b/contrib/amcheck/amcheck.control
@@ -1,5 +1,5 @@
# amcheck extension
comment = 'functions for verifying relation integrity'
-default_version = '1.2'
+default_version = '1.2.1'
module_pathname = '$libdir/amcheck'
relocatable = true
diff --git a/contrib/amcheck/amcheck.h b/contrib/amcheck/amcheck.h
new file mode 100644
index 0000000000..b19e617177
--- /dev/null
+++ b/contrib/amcheck/amcheck.h
@@ -0,0 +1,23 @@
+/*-------------------------------------------------------------------------
+ *
+ * amcheck.h
+ * Shared routines for amcheck verifications.
+ *
+ * Copyright (c) 2019, PostgreSQL Global Development Group
+ *
+ * IDENTIFICATION
+ * contrib/amcheck/amcheck.h
+ *
+ *-------------------------------------------------------------------------
+ */
+#include "storage/lockdefs.h"
+#include "utils/relcache.h"
+
+extern void amcheck_lock_relation(Oid indrelid, Relation *indrel,
+ Relation *heaprel, LOCKMODE lockmode);
+extern void amcheck_unlock_relation(Oid indrelid, Relation indrel,
+ Relation heaprel, LOCKMODE lockmode);
+extern bool amcheck_index_mainfork_expected(Relation rel);
+
+extern ItemId PageGetItemIdCareful(Relation rel, BlockNumber block,
+ Page page, OffsetNumber offset, size_t opaquesize);
\ No newline at end of file
diff --git a/contrib/amcheck/expected/check_gin.out b/contrib/amcheck/expected/check_gin.out
new file mode 100644
index 0000000000..35e3f0dc33
--- /dev/null
+++ b/contrib/amcheck/expected/check_gin.out
@@ -0,0 +1,60 @@
+-- minimal test, basically just verifying that amcheck works with GIN
+SELECT setseed(1);
+ setseed
+---------
+
+(1 row)
+
+CREATE TABLE "gin_check"("Column1" int[]);
+-- posting trees
+INSERT INTO gin_check select array_agg(round(random()*255) ) from generate_series(1, 1000000) as i group by i % 100000;
+-- posting leaves
+INSERT INTO gin_check select array_agg(255 + round(random()*100)) from generate_series(1, 100) as i group by i % 100;
+CREATE INDEX gin_check_idx on "gin_check" USING GIN("Column1");
+SELECT gin_index_parent_check('gin_check_idx');
+ gin_index_parent_check
+------------------------
+
+(1 row)
+
+-- cleanup
+DROP TABLE gin_check;
+-- minimal test, basically just verifying that amcheck works with GIN
+SELECT setseed(1);
+ setseed
+---------
+
+(1 row)
+
+CREATE TABLE "gin_check"("Column1" int[]);
+CREATE INDEX gin_check_idx on "gin_check" USING GIN("Column1");
+ALTER INDEX gin_check_idx SET (fastupdate = false);
+-- posting trees
+INSERT INTO gin_check select array_agg(round(random()*255) ) from generate_series(1, 1000000) as i group by i % 100000;
+-- posting leaves
+INSERT INTO gin_check select array_agg(100 + round(random()*255)) from generate_series(1, 100) as i group by i % 100;
+SELECT gin_index_parent_check('gin_check_idx');
+ gin_index_parent_check
+------------------------
+
+(1 row)
+
+-- cleanup
+DROP TABLE gin_check;
+-- minimal test, basically just verifying that amcheck works with GIN
+SELECT setseed(1);
+ setseed
+---------
+
+(1 row)
+
+CREATE TABLE "gin_check_text_array"("Column1" text[]);
+-- posting trees
+INSERT INTO gin_check_text_array select array_agg(md5(round(random()*300)::text)::text) from generate_series(1, 1000000) as i group by i % 100000;
+-- posting leaves
+INSERT INTO gin_check_text_array select array_agg(md5(round(random()*300 + 300)::text)::text) from generate_series(1, 10000) as i group by i % 100;
+CREATE INDEX gin_check_text_array_idx on "gin_check_text_array" USING GIN("Column1");
+SELECT gin_index_parent_check('gin_check_text_array');
+ERROR: "gin_check_text_array" is not an index
+-- cleanup
+DROP TABLE gin_check_text_array;
diff --git a/contrib/amcheck/sql/check_gin.sql b/contrib/amcheck/sql/check_gin.sql
new file mode 100644
index 0000000000..c81db477f1
--- /dev/null
+++ b/contrib/amcheck/sql/check_gin.sql
@@ -0,0 +1,40 @@
+-- minimal test, basically just verifying that amcheck works with GIN
+SELECT setseed(1);
+CREATE TABLE "gin_check"("Column1" int[]);
+-- posting trees
+INSERT INTO gin_check select array_agg(round(random()*255) ) from generate_series(1, 1000000) as i group by i % 100000;
+-- posting leaves
+INSERT INTO gin_check select array_agg(255 + round(random()*100)) from generate_series(1, 100) as i group by i % 100;
+CREATE INDEX gin_check_idx on "gin_check" USING GIN("Column1");
+SELECT gin_index_parent_check('gin_check_idx');
+
+-- cleanup
+DROP TABLE gin_check;
+
+-- minimal test, basically just verifying that amcheck works with GIN
+SELECT setseed(1);
+CREATE TABLE "gin_check"("Column1" int[]);
+CREATE INDEX gin_check_idx on "gin_check" USING GIN("Column1");
+ALTER INDEX gin_check_idx SET (fastupdate = false);
+-- posting trees
+INSERT INTO gin_check select array_agg(round(random()*255) ) from generate_series(1, 1000000) as i group by i % 100000;
+-- posting leaves
+INSERT INTO gin_check select array_agg(100 + round(random()*255)) from generate_series(1, 100) as i group by i % 100;
+
+SELECT gin_index_parent_check('gin_check_idx');
+
+-- cleanup
+DROP TABLE gin_check;
+
+-- minimal test, basically just verifying that amcheck works with GIN
+SELECT setseed(1);
+CREATE TABLE "gin_check_text_array"("Column1" text[]);
+-- posting trees
+INSERT INTO gin_check_text_array select array_agg(md5(round(random()*300)::text)::text) from generate_series(1, 1000000) as i group by i % 100000;
+-- posting leaves
+INSERT INTO gin_check_text_array select array_agg(md5(round(random()*300 + 300)::text)::text) from generate_series(1, 10000) as i group by i % 100;
+CREATE INDEX gin_check_text_array_idx on "gin_check_text_array" USING GIN("Column1");
+SELECT gin_index_parent_check('gin_check_text_array');
+
+-- cleanup
+DROP TABLE gin_check_text_array;
diff --git a/contrib/amcheck/verify_gin.c b/contrib/amcheck/verify_gin.c
new file mode 100644
index 0000000000..460004ad60
--- /dev/null
+++ b/contrib/amcheck/verify_gin.c
@@ -0,0 +1,822 @@
+/*-------------------------------------------------------------------------
+ *
+ * verify_gin.c
+ * Verifies the integrity of GIN indexes based on invariants.
+ *
+ * Verification checks that all paths in GIN graph contain
+ * consistent keys: tuples on parent pages consistently include tuples
+ * from children pages. Also, verification checks graph invariants:
+ * internal page must have at least one downlinks, internal page can
+ * reference either only leaf pages or only internal pages.
+ *
+ *
+ * Copyright (c) 2017-2019, PostgreSQL Global Development Group
+ *
+ * IDENTIFICATION
+ * contrib/amcheck/verify_gin.c
+ *
+ *-------------------------------------------------------------------------
+ */
+#include "postgres.h"
+
+#include "access/gin_private.h"
+#include "access/nbtree.h"
+#include "amcheck.h"
+#include "catalog/pg_am.h"
+#include "miscadmin.h"
+#include "utils/memutils.h"
+#include "utils/rel.h"
+#include "string.h"
+
+/*
+ * GinScanItem represents one item of depth-first scan of GIN index.
+ */
+typedef struct GinScanItem
+{
+ int depth;
+ IndexTuple parenttup;
+ BlockNumber parentblk;
+ XLogRecPtr parentlsn;
+ BlockNumber blkno;
+ struct GinScanItem *next;
+} GinScanItem;
+
+/*
+ * GinPostingTreeScanItem represents one item of depth-first scan of GIN posting tree.
+ */
+typedef struct GinPostingTreeScanItem
+{
+ int depth;
+ ItemPointerData parentkey;
+ BlockNumber parentblk;
+ BlockNumber blkno;
+ struct GinPostingTreeScanItem *next;
+} GinPostingTreeScanItem;
+
+
+PG_FUNCTION_INFO_V1(gin_index_parent_check);
+
+static void gin_index_checkable(Relation rel);
+static void gin_check_parent_keys_consistency(Relation rel);
+static bool check_index_page(Relation rel, Buffer buffer, BlockNumber blockNo);
+static IndexTuple gin_refind_parent(Relation rel, BlockNumber parentblkno,
+ BlockNumber childblkno,
+ BufferAccessStrategy strategy);
+
+/*
+ * gin_index_parent_check(index regclass)
+ *
+ * Verify integrity of GIN index.
+ *
+ * Acquires AccessShareLock on heap & index relations.
+ */
+Datum
+gin_index_parent_check(PG_FUNCTION_ARGS)
+{
+ Oid indrelid = PG_GETARG_OID(0);
+ Relation indrel;
+ Relation heaprel;
+ LOCKMODE lockmode = AccessShareLock;
+
+ /* lock table and index with neccesary level */
+ amcheck_lock_relation(indrelid, &indrel, &heaprel, lockmode);
+
+ /* verify that this is GIN eligible for check */
+ gin_index_checkable(indrel);
+
+ if (amcheck_index_mainfork_expected(indrel))
+ gin_check_parent_keys_consistency(indrel);
+
+ /* Unlock index and table */
+ amcheck_unlock_relation(indrelid, indrel, heaprel, lockmode);
+
+ PG_RETURN_VOID();
+}
+
+/*
+ * Read item pointers from leaf entry tuple.
+ *
+ * Returns a palloc'd array of ItemPointers. The number of items is returned
+ * in *nitems.
+ */
+static ItemPointer
+ginReadTupleWithoutState(IndexTuple itup, int *nitems)
+{
+ Pointer ptr = GinGetPosting(itup);
+ int nipd = GinGetNPosting(itup);
+ ItemPointer ipd;
+ int ndecoded;
+
+ if (GinItupIsCompressed(itup))
+ {
+ if (nipd > 0)
+ {
+ ipd = ginPostingListDecode((GinPostingList *) ptr, &ndecoded);
+ if (nipd != ndecoded)
+ elog(ERROR, "number of items mismatch in GIN entry tuple, %d in tuple header, %d decoded",
+ nipd, ndecoded);
+ }
+ else
+ {
+ ipd = palloc(0);
+ }
+ }
+ else
+ {
+ ipd = (ItemPointer) palloc(sizeof(ItemPointerData) * nipd);
+ memcpy(ipd, ptr, sizeof(ItemPointerData) * nipd);
+ }
+ *nitems = nipd;
+ return ipd;
+}
+
+
+/*
+ * Check that relation is eligible for GIN verification
+ */
+static void
+gin_index_checkable(Relation rel)
+{
+ if (rel->rd_rel->relkind != RELKIND_INDEX ||
+ rel->rd_rel->relam != GIN_AM_OID)
+ ereport(ERROR,
+ (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+ errmsg("only GIN indexes are supported as targets for this verification"),
+ errdetail("Relation \"%s\" is not a GIN index.",
+ RelationGetRelationName(rel))));
+
+ if (RELATION_IS_OTHER_TEMP(rel))
+ ereport(ERROR,
+ (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+ errmsg("cannot access temporary tables of other sessions"),
+ errdetail("Index \"%s\" is associated with temporary relation.",
+ RelationGetRelationName(rel))));
+
+ if (!rel->rd_index->indisvalid)
+ ereport(ERROR,
+ (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+ errmsg("cannot check index \"%s\"",
+ RelationGetRelationName(rel)),
+ errdetail("Index is not valid")));
+}
+
+/*
+ * Allocates memory context and scans through postigTree graph
+ *
+ */
+static void
+gin_check_posting_tree_parent_keys_consistency(Relation rel, BlockNumber posting_tree_root)
+{
+ BufferAccessStrategy strategy = GetAccessStrategy(BAS_BULKREAD);
+ GinPostingTreeScanItem *stack;
+ MemoryContext mctx;
+ MemoryContext oldcontext;
+
+ int leafdepth;
+
+ mctx = AllocSetContextCreate(CurrentMemoryContext,
+ "amcheck context",
+ ALLOCSET_DEFAULT_SIZES);
+ oldcontext = MemoryContextSwitchTo(mctx);
+
+ /*
+ * We don't know the height of the tree yet, but as soon as we encounter a
+ * leaf page, we will set 'leafdepth' to its depth.
+ */
+ leafdepth = -1;
+
+ /* Start the scan at the root page */
+ stack = (GinPostingTreeScanItem *) palloc0(sizeof(GinPostingTreeScanItem));
+ stack->depth = 0;
+ ItemPointerSetInvalid(&stack->parentkey);
+ stack->parentblk = InvalidBlockNumber;
+ stack->blkno = posting_tree_root;
+
+ elog(INFO, "processing posting tree at blk %u", posting_tree_root);
+
+ while (stack)
+ {
+ GinPostingTreeScanItem *stack_next;
+ Buffer buffer;
+ Page page;
+ OffsetNumber i,
+ maxoff;
+
+ //elog(INFO, "processing block %u", stack->blkno);
+
+ CHECK_FOR_INTERRUPTS();
+
+ buffer = ReadBufferExtended(rel, MAIN_FORKNUM, stack->blkno,
+ RBM_NORMAL, strategy);
+ LockBuffer(buffer, GIN_SHARE);
+ page = (Page) BufferGetPage(buffer);
+ Assert(GinPageIsData(page));
+
+ /* Check that the tree has the same height in all branches */
+ if (GinPageIsLeaf(page))
+ {
+ ItemPointerData minItem;
+ int nlist;
+ ItemPointerData *list;
+
+ ItemPointerSetMin(&minItem);
+
+ if (leafdepth == -1)
+ leafdepth = stack->depth;
+ else if (stack->depth != leafdepth)
+ ereport(ERROR,
+ (errcode(ERRCODE_INDEX_CORRUPTED),
+ errmsg("index \"%s\": internal pages traversal encountered leaf page unexpectedly on block %u",
+ RelationGetRelationName(rel), stack->blkno)));
+ list = GinDataLeafPageGetItems(page, &nlist, minItem);
+ if (stack->parentblk != InvalidBlockNumber)
+ {
+ elog(INFO, "blk %u: parent %u highkey (%u, %u), %d tids (%u, %u) - (%u, %u)",
+ stack->blkno,
+ stack->parentblk,
+ ItemPointerGetBlockNumberNoCheck(&stack->parentkey),
+ ItemPointerGetOffsetNumberNoCheck(&stack->parentkey),
+ nlist,
+ ItemPointerGetBlockNumberNoCheck(&list[0]),
+ ItemPointerGetOffsetNumberNoCheck(&list[0]),
+ ItemPointerGetBlockNumberNoCheck(&list[nlist - 1]),
+ ItemPointerGetOffsetNumberNoCheck(&list[nlist - 1]));
+ }
+ else
+ {
+ elog(INFO, "blk %u: root leaf %d tids (%u, %u) - (%u, %u)",
+ stack->blkno,
+ nlist,
+ ItemPointerGetBlockNumberNoCheck(&list[0]),
+ ItemPointerGetOffsetNumberNoCheck(&list[0]),
+ ItemPointerGetBlockNumberNoCheck(&list[nlist - 1]),
+ ItemPointerGetOffsetNumberNoCheck(&list[nlist - 1]));
+ }
+
+ if (stack->parentblk != InvalidBlockNumber &&
+ ItemPointerGetOffsetNumberNoCheck(&stack->parentkey) != InvalidOffsetNumber &&
+ ItemPointerCompare(&stack->parentkey, &list[nlist - 1]) < 0)
+ {
+ ereport(WARNING,
+ (errcode(ERRCODE_INDEX_CORRUPTED),
+ errmsg("index \"%s\": tid exceeds parent's high key in postingTree leaf on block %u",
+ RelationGetRelationName(rel), stack->blkno)));
+ }
+ }
+ else
+ {
+ LocationIndex pd_lower;
+ int lowersize;
+ ItemPointerData bound;
+
+ /*
+ * Check that tuples in each page are properly ordered and
+ * consistent with parent high key
+ */
+ maxoff = GinPageGetOpaque(page)->maxoff;
+ if (stack->parentblk != InvalidBlockNumber)
+ elog(INFO, "blk %u: internal posting tree page with %u items, parent %u highkey (%u, %u)",
+ stack->blkno,
+ maxoff,
+ stack->parentblk,
+ ItemPointerGetBlockNumberNoCheck(&stack->parentkey),
+ ItemPointerGetOffsetNumberNoCheck(&stack->parentkey));
+ else
+ elog(INFO, "blk %u: root internal posting tree page with %u items", stack->blkno, maxoff);
+
+ /*
+ * A GIN posting tree internal page stores PostingItems in the
+ * 'lower' part of the page. The 'upper' part is unused. The
+ * number of elements is stored in the opaque area (maxoff).
+ * Make sure the size of the 'lower' part agrees with 'maxoff'
+ *
+ * We didn't set pd_lower until PostgreSQL version 9.4, so if this
+ * check fails, it could also be because the index was binary-upgraded
+ * from an earlier version. That was a long time ago, though, so let's
+ * warn if it doesn't match.
+ */
+ pd_lower = ((PageHeader) page)->pd_lower;
+ lowersize = pd_lower - MAXALIGN(SizeOfPageHeaderData);
+ if ((lowersize - MAXALIGN(sizeof(ItemPointerData))) / sizeof(PostingItem) != maxoff)
+ {
+ ereport(WARNING,
+ (errcode(ERRCODE_INDEX_CORRUPTED),
+ errmsg("index \"%s\" has unexpected pd_lower %u in posting tree block %u with maxoff %u)",
+ RelationGetRelationName(rel), pd_lower, stack->blkno, maxoff)));
+ }
+
+ /*
+ * Before the PostingItems, there's one ItemPointerData in the
+ * 'lower' part that stores the page's high key.
+ */
+ bound = *GinDataPageGetRightBound(page);
+
+ if (stack->parentblk != InvalidBlockNumber)
+ {
+ if (!ItemPointerEquals(&stack->parentkey, &bound))
+ {
+ ereport(WARNING,
+ (errcode(ERRCODE_INDEX_CORRUPTED),
+ errmsg("index \"%s\": posting tree page's high key (%u, %u) doesn't match the downlink on block %u (parent blk %u, key (%u, %u))",
+ RelationGetRelationName(rel),
+ ItemPointerGetBlockNumberNoCheck(&bound),
+ ItemPointerGetOffsetNumberNoCheck(&bound),
+ stack->blkno,
+ stack->parentblk,
+ ItemPointerGetBlockNumberNoCheck(&stack->parentkey),
+ ItemPointerGetOffsetNumberNoCheck(&stack->parentkey))));
+ }
+ }
+
+ for (i = FirstOffsetNumber; i <= maxoff; i = OffsetNumberNext(i))
+ {
+ PostingItem *posting_item = GinDataPageGetPostingItem(page, i);
+
+ elog(INFO, "key (%u, %u) -> %u",
+ ItemPointerGetBlockNumber(&posting_item->key),
+ ItemPointerGetOffsetNumber(&posting_item->key),
+ BlockIdGetBlockNumber(&posting_item->child_blkno));
+
+ if (i == maxoff && GinPageGetOpaque(page)->rightlink == InvalidBlockNumber)
+ {
+ /* The rightmost item in the tree level has (0, 0) as the key */
+ if (ItemPointerGetBlockNumberNoCheck(&posting_item->key) != 0 ||
+ ItemPointerGetOffsetNumberNoCheck(&posting_item->key) != 0)
+ {
+ ereport(WARNING,
+ (errcode(ERRCODE_INDEX_CORRUPTED),
+ errmsg("index \"%s\": rightmost posting tree page (blk %u) has unexpected last key (%u, %u)",
+ RelationGetRelationName(rel),
+ stack->blkno,
+ ItemPointerGetBlockNumberNoCheck(&posting_item->key),
+ ItemPointerGetOffsetNumberNoCheck(&posting_item->key))));
+ }
+ }
+ else if (i != FirstOffsetNumber)
+ {
+ PostingItem *previous_posting_item = GinDataPageGetPostingItem(page, i - 1);
+
+ if (ItemPointerCompare(&posting_item->key, &previous_posting_item->key) < 0)
+ {
+ ereport(WARNING,
+ (errcode(ERRCODE_INDEX_CORRUPTED),
+ errmsg("index \"%s\" has wrong tuple order in posting tree, block %u, offset %u",
+ RelationGetRelationName(rel), stack->blkno, i)));
+ }
+ }
+
+ /*
+ * Check if this tuple is consistent with the downlink in the
+ * parent.
+ */
+ if (stack->parentblk != InvalidBlockNumber && i == maxoff)
+ {
+ if (ItemPointerCompare(&stack->parentkey, &posting_item->key) < 0)
+ {
+ ereport(WARNING,
+ (errcode(ERRCODE_INDEX_CORRUPTED),
+ errmsg("index \"%s\": posting item exceeds parent's high key in postingTree internal page on block %u offset %u",
+ RelationGetRelationName(rel), stack->blkno, i)));
+
+ }
+ }
+
+ /* If this is an internal page, recurse into the child */
+ if (!GinPageIsLeaf(page))
+ {
+ GinPostingTreeScanItem *ptr;
+
+ ptr = (GinPostingTreeScanItem *) palloc(sizeof(GinPostingTreeScanItem));
+ ptr->depth = stack->depth + 1;
+ ptr->parentkey = posting_item->key;
+ ptr->parentblk = stack->blkno;
+ ptr->blkno = BlockIdGetBlockNumber(&posting_item->child_blkno);
+ ptr->next = stack->next;
+ stack->next = ptr;
+ }
+
+ }
+ }
+ LockBuffer(buffer, GIN_UNLOCK);
+ ReleaseBuffer(buffer);
+
+ /* Step to next item in the queue */
+ stack_next = stack->next;
+ pfree(stack);
+ stack = stack_next;
+ }
+
+ MemoryContextSwitchTo(oldcontext);
+ MemoryContextDelete(mctx);
+}
+
+static void
+validate_leaf(Page page, Relation rel, BlockNumber blkno)
+{
+ OffsetNumber i,
+ maxoff;
+
+ maxoff = PageGetMaxOffsetNumber(page);
+ for (i = FirstOffsetNumber; i <= maxoff; i = OffsetNumberNext(i))
+ {
+ ItemId iid = PageGetItemIdCareful(rel, blkno, page, i, sizeof(GinPageOpaqueData));
+ IndexTuple idxtuple = (IndexTuple) PageGetItem(page, iid);
+
+ if (GinIsPostingTree(idxtuple))
+ {
+/* elog(INFO, "validating posting tree on page %u, block %u, offset %u", page, blkno, i); */
+ BlockNumber rootPostingTree = GinGetPostingTree(idxtuple);
+
+ gin_check_posting_tree_parent_keys_consistency(rel, rootPostingTree);
+ }
+ else
+ {
+/* elog(INFO, "validating posting list on page %u, block %u, offset %u", page, blkno, i); */
+
+ ItemPointer ipd;
+ int nipd;
+
+ ipd = ginReadTupleWithoutState(idxtuple, &nipd);
+ if (!OffsetNumberIsValid(ItemPointerGetOffsetNumber(&ipd[nipd - 1])))
+ {
+ ereport(WARNING,
+ (errcode(ERRCODE_INDEX_CORRUPTED),
+ errmsg("index \"%s\": posting list contains invalid heap pointer on block %u",
+ RelationGetRelationName(rel), blkno)));
+ }
+ pfree(ipd);
+ }
+ }
+}
+
+/*
+ * Main entry point for GIN check. Allocates memory context and scans through
+ * GIN graph.
+ */
+static void
+gin_check_parent_keys_consistency(Relation rel)
+{
+ BufferAccessStrategy strategy = GetAccessStrategy(BAS_BULKREAD);
+ GinScanItem *stack;
+ MemoryContext mctx;
+ MemoryContext oldcontext;
+ GinState state;
+
+ int leafdepth;
+
+ mctx = AllocSetContextCreate(CurrentMemoryContext,
+ "amcheck context",
+ ALLOCSET_DEFAULT_SIZES);
+ oldcontext = MemoryContextSwitchTo(mctx);
+ initGinState(&state, rel);
+
+ /*
+ * We don't know the height of the tree yet, but as soon as we encounter a
+ * leaf page, we will set 'leafdepth' to its depth.
+ */
+ leafdepth = -1;
+
+ /* Start the scan at the root page */
+ stack = (GinScanItem *) palloc0(sizeof(GinScanItem));
+ stack->depth = 0;
+ stack->parenttup = NULL;
+ stack->parentblk = InvalidBlockNumber;
+ stack->parentlsn = InvalidXLogRecPtr;
+ stack->blkno = GIN_ROOT_BLKNO;
+
+ while (stack)
+ {
+ GinScanItem *stack_next;
+ Buffer buffer;
+ Page page;
+ OffsetNumber i,
+ maxoff;
+ XLogRecPtr lsn;
+ IndexTuple prev_tuple;
+
+ //elog(INFO, "processing block %u", stack->blkno);
+
+ CHECK_FOR_INTERRUPTS();
+
+ buffer = ReadBufferExtended(rel, MAIN_FORKNUM, stack->blkno,
+ RBM_NORMAL, strategy);
+ LockBuffer(buffer, GIN_SHARE);
+ page = (Page) BufferGetPage(buffer);
+ lsn = BufferGetLSNAtomic(buffer);
+
+ /* Do basic sanity checks on the page headers */
+ if (!check_index_page(rel, buffer, stack->blkno))
+ {
+ goto nextpage;
+ }
+
+ /*
+ * It's possible that the page was split since we looked at the
+ * parent, so that we didn't missed the downlink of the right sibling
+ * when we scanned the parent. If so, add the right sibling to the
+ * stack now.
+ */
+ if (stack->parenttup != NULL)
+ {
+ GinNullCategory parent_key_category;
+ Datum parent_key = gintuple_get_key(&state, stack->parenttup, &parent_key_category);
+ OffsetNumber maxoff = PageGetMaxOffsetNumber(page);
+ ItemId iid = PageGetItemIdCareful(rel, stack->blkno, page, maxoff, sizeof(GinPageOpaqueData));
+ IndexTuple idxtuple = (IndexTuple) PageGetItem(page, iid);
+ OffsetNumber attnum = gintuple_get_attrnum(&state, idxtuple);
+ GinNullCategory page_max_key_category;
+ Datum page_max_key = gintuple_get_key(&state, idxtuple, &page_max_key_category);
+
+ if (GinPageGetOpaque(page)->rightlink != InvalidBlockNumber &&
+ ginCompareEntries(&state, attnum, page_max_key, page_max_key_category, parent_key, parent_key_category) > 0)
+ {
+ /* split page detected, install right link to the stack */
+ GinScanItem *ptr;
+
+ elog(INFO, "split detected");
+
+ ptr = (GinScanItem *) palloc(sizeof(GinScanItem));
+ ptr->depth = stack->depth;
+ ptr->parenttup = CopyIndexTuple(stack->parenttup);
+ ptr->parentblk = stack->parentblk;
+ ptr->parentlsn = stack->parentlsn;
+ ptr->blkno = GinPageGetOpaque(page)->rightlink;
+ ptr->next = stack->next;
+ stack->next = ptr;
+ }
+ }
+
+ /* Check that the tree has the same height in all branches */
+ if (GinPageIsLeaf(page))
+ {
+ if (leafdepth == -1)
+ leafdepth = stack->depth;
+ else if (stack->depth != leafdepth)
+ {
+ ereport(WARNING,
+ (errcode(ERRCODE_INDEX_CORRUPTED),
+ errmsg("index \"%s\": internal pages traversal encountered leaf page unexpectedly on block %u",
+ RelationGetRelationName(rel), stack->blkno)));
+ goto nextpage;
+ }
+ }
+
+ /*
+ * Check that tuples in each page are properly ordered and consistent
+ * with parent high key
+ */
+ maxoff = PageGetMaxOffsetNumber(page);
+ prev_tuple = NULL;
+ for (i = FirstOffsetNumber; i <= maxoff; i = OffsetNumberNext(i))
+ {
+ ItemId iid = PageGetItemIdCareful(rel, stack->blkno, page, i, sizeof(GinPageOpaqueData));
+ IndexTuple idxtuple = (IndexTuple) PageGetItem(page, iid);
+ OffsetNumber attnum = gintuple_get_attrnum(&state, idxtuple);
+ GinNullCategory prev_key_category;
+ Datum prev_key;
+ GinNullCategory current_key_category;
+ Datum current_key;
+
+ if (MAXALIGN(ItemIdGetLength(iid)) != MAXALIGN(IndexTupleSize(idxtuple)))
+ {
+ ereport(WARNING,
+ (errcode(ERRCODE_INDEX_CORRUPTED),
+ errmsg("index \"%s\" has inconsistent tuple sizes, block %u, offset %u",
+ RelationGetRelationName(rel), stack->blkno, i)));
+ continue;
+ }
+
+ current_key = gintuple_get_key(&state, idxtuple, ¤t_key_category);
+/* elog(INFO, "current_key %s, depth %u", DatumGetCString(current_key), stack->depth); */
+
+ /* (apparently) first block is metadata, skip order check */
+ if (i != FirstOffsetNumber && stack->blkno != (BlockNumber) 1)
+ {
+ prev_key = gintuple_get_key(&state, prev_tuple, &prev_key_category);
+ if (ginCompareEntries(&state, attnum, prev_key, prev_key_category, current_key, current_key_category) >= 0)
+ {
+ ereport(WARNING,
+ (errcode(ERRCODE_INDEX_CORRUPTED),
+ errmsg("index \"%s\" has wrong tuple order, block %u, offset %u",
+ RelationGetRelationName(rel), stack->blkno, i)));
+ }
+ }
+
+ /*
+ * Check if this tuple is consistent with the downlink in the
+ * parent.
+ */
+ if (stack->parenttup &&
+ i == maxoff)
+ {
+ GinNullCategory parent_key_category;
+ Datum parent_key = gintuple_get_key(&state, stack->parenttup, &parent_key_category);
+
+ if (ginCompareEntries(&state, attnum, current_key, current_key_category, parent_key, parent_key_category) > 0)
+ {
+ /*
+ * There was a discrepancy between parent and child
+ * tuples. We need to verify it is not a result of
+ * concurrent call of gistplacetopage(). So, lock parent
+ * and try to find downlink for current page. It may be
+ * missing due to concurrent page split, this is OK.
+ */
+ pfree(stack->parenttup);
+ stack->parenttup = gin_refind_parent(rel, stack->parentblk,
+ stack->blkno, strategy);
+
+ /* We found it - make a final check before failing */
+ if (!stack->parenttup)
+ elog(NOTICE, "Unable to find parent tuple for block %u on block %u due to concurrent split",
+ stack->blkno, stack->parentblk);
+ else
+ {
+ parent_key = gintuple_get_key(&state, stack->parenttup, &parent_key_category);
+ if (ginCompareEntries(&state, attnum, current_key, current_key_category, parent_key, parent_key_category) > 0)
+ ereport(ERROR,
+ (errcode(ERRCODE_INDEX_CORRUPTED),
+ errmsg("index \"%s\" has inconsistent records on page %u offset %u",
+ RelationGetRelationName(rel), stack->blkno, i)));
+ else
+ {
+ /*
+ * But now it is properly adjusted - nothing to do
+ * here.
+ */
+ }
+ }
+ }
+ }
+
+ /* If this is an internal page, recurse into the child */
+ if (!GinPageIsLeaf(page))
+ {
+ GinScanItem *ptr;
+
+ ptr = (GinScanItem *) palloc(sizeof(GinScanItem));
+ ptr->depth = stack->depth + 1;
+ /* last tuple in layer has no high key */
+ if (i != maxoff && !GinPageGetOpaque(page)->rightlink)
+ {
+ ptr->parenttup = CopyIndexTuple(idxtuple);
+ }
+ else
+ {
+ ptr->parenttup = NULL;
+ }
+ ptr->parentblk = stack->blkno;
+ ptr->blkno = ItemPointerGetBlockNumber(&(idxtuple->t_tid));
+ ptr->parentlsn = lsn;
+ ptr->next = stack->next;
+ stack->next = ptr;
+ }
+ else
+ {
+ validate_leaf(page, rel, stack->blkno);
+ }
+
+
+ prev_tuple = CopyIndexTuple(idxtuple);
+ }
+
+nextpage:
+ LockBuffer(buffer, GIN_UNLOCK);
+ ReleaseBuffer(buffer);
+
+ /* Step to next item in the queue */
+ stack_next = stack->next;
+ if (stack->parenttup)
+ pfree(stack->parenttup);
+ pfree(stack);
+ stack = stack_next;
+ }
+
+ MemoryContextSwitchTo(oldcontext);
+ MemoryContextDelete(mctx);
+}
+
+/*
+ * Verify that a freshly-read page looks sane.
+ */
+static bool
+gincheckpage(Relation rel, Buffer buf)
+{
+ Page page = BufferGetPage(buf);
+
+ /*
+ * ReadBuffer verifies that every newly-read page passes
+ * PageHeaderIsValid, which means it either contains a reasonably sane
+ * page header or is all-zero. We have to defend against the all-zero
+ * case, however.
+ */
+ if (PageIsNew(page))
+ {
+ ereport(WARNING,
+ (errcode(ERRCODE_INDEX_CORRUPTED),
+ errmsg("index \"%s\" contains unexpected zero page at block %u",
+ RelationGetRelationName(rel),
+ BufferGetBlockNumber(buf)),
+ errhint("Please REINDEX it.")));
+ return false;
+ }
+
+ /*
+ * Additionally check that the special area looks sane.
+ */
+ if (PageGetSpecialSize(page) != MAXALIGN(sizeof(GinPageOpaqueData)))
+ {
+ ereport(WARNING,
+ (errcode(ERRCODE_INDEX_CORRUPTED),
+ errmsg("index \"%s\" contains corrupted page at block %u",
+ RelationGetRelationName(rel),
+ BufferGetBlockNumber(buf)),
+ errhint("Please REINDEX it.")));
+ return false;
+ }
+ return true;
+}
+
+static bool
+check_index_page(Relation rel, Buffer buffer, BlockNumber blockNo)
+{
+ Page page = BufferGetPage(buffer);
+
+ if (!gincheckpage(rel, buffer))
+ return false;
+
+ if (GinPageIsDeleted(page))
+ {
+ if (!GinPageIsLeaf(page))
+ {
+ ereport(WARNING,
+ (errcode(ERRCODE_INDEX_CORRUPTED),
+ errmsg("index \"%s\" has deleted internal page %d",
+ RelationGetRelationName(rel), blockNo)));
+ return false;
+ }
+ if (PageGetMaxOffsetNumber(page) > InvalidOffsetNumber)
+ {
+ ereport(WARNING,
+ (errcode(ERRCODE_INDEX_CORRUPTED),
+ errmsg("index \"%s\" has deleted page %d with tuples",
+ RelationGetRelationName(rel), blockNo)));
+ return false;
+ }
+ }
+ else if (PageGetMaxOffsetNumber(page) > MaxIndexTuplesPerPage)
+ {
+ ereport(WARNING,
+ (errcode(ERRCODE_INDEX_CORRUPTED),
+ errmsg("index \"%s\" has page %d with exceeding count of tuples",
+ RelationGetRelationName(rel), blockNo)));
+ return false;
+ }
+ return true;
+}
+
+/*
+ * Try to re-find downlink pointing to 'blkno', in 'parentblkno'.
+ *
+ * If found, returns a palloc'd copy of the downlink tuple. Otherwise,
+ * returns NULL.
+ */
+static IndexTuple
+gin_refind_parent(Relation rel, BlockNumber parentblkno,
+ BlockNumber childblkno, BufferAccessStrategy strategy)
+{
+ Buffer parentbuf;
+ Page parentpage;
+ OffsetNumber o,
+ parent_maxoff;
+ IndexTuple result = NULL;
+
+ parentbuf = ReadBufferExtended(rel, MAIN_FORKNUM, parentblkno, RBM_NORMAL,
+ strategy);
+
+ LockBuffer(parentbuf, GIN_SHARE);
+ parentpage = BufferGetPage(parentbuf);
+
+ if (GinPageIsLeaf(parentpage))
+ {
+ UnlockReleaseBuffer(parentbuf);
+ return result;
+ }
+
+ parent_maxoff = PageGetMaxOffsetNumber(parentpage);
+ for (o = FirstOffsetNumber; o <= parent_maxoff; o = OffsetNumberNext(o))
+ {
+ ItemId p_iid = PageGetItemIdCareful(rel, parentblkno, parentpage, o, sizeof(GinPageOpaqueData));
+ IndexTuple itup = (IndexTuple) PageGetItem(parentpage, p_iid);
+
+ if (ItemPointerGetBlockNumber(&(itup->t_tid)) == childblkno)
+ {
+ /* Found it! Make copy and return it */
+ result = CopyIndexTuple(itup);
+ break;
+ }
+ }
+
+ UnlockReleaseBuffer(parentbuf);
+
+ return result;
+}
diff --git a/doc/src/sgml/amcheck.sgml b/doc/src/sgml/amcheck.sgml
index 75518a7820..51f08a4423 100644
--- a/doc/src/sgml/amcheck.sgml
+++ b/doc/src/sgml/amcheck.sgml
@@ -165,6 +165,25 @@ ORDER BY c.relpages DESC LIMIT 10;
</para>
</listitem>
</varlistentry>
+
+ <varlistentry>
+ <term>
+ <function>gin_index_parent_check(index regclass) returns void</function>
+ <indexterm>
+ <primary>gin_index_parent_check</primary>
+ </indexterm>
+ </term>
+
+ <listitem>
+ <para>
+ <function>gin_index_parent_check</function> tests that its target GIN index
+ has consistent parent-child tuples relations (no parent tuples
+ require tuple adjustement) and page graph respects balanced-tree
+ invariants (internal pages reference only leaf page or only internal
+ pages).
+ </para>
+ </listitem>
+ </varlistentry>
</variablelist>
<tip>
<para>
--
2.30.2
--------------01E330C3D386A84FA9B9E425--