From 38ef30684b0248bae0d0e82e3919118ed629613f Mon Sep 17 00:00:00 2001 From: Heikki Linnakangas Date: Thu, 15 Jul 2021 08:51:35 +0300 Subject: [PATCH v2 1/1] Amcheck for GIN Author: Grigory Kryachko Discussion: https://www.postgresql.org/message-id/CAF3eApa07-BajjG8%2BRYx-Dr_cq28ZA0GsZmUQrGu5b2ayRhB5A%40mail.gmail.com --- contrib/amcheck/Makefile | 8 +- contrib/amcheck/amcheck--1.3--1.4.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 | 695 +++++++++++++++++++++++++ doc/src/sgml/amcheck.sgml | 19 + 9 files changed, 1020 insertions(+), 3 deletions(-) create mode 100644 contrib/amcheck/amcheck--1.3--1.4.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 b82f221e50b..3418c30c50b 100644 --- a/contrib/amcheck/Makefile +++ b/contrib/amcheck/Makefile @@ -3,14 +3,18 @@ MODULE_big = amcheck OBJS = \ $(WIN32RES) \ + amcheck.o \ + verify_gin.o \ verify_heapam.o \ verify_nbtree.o EXTENSION = amcheck -DATA = amcheck--1.2--1.3.sql amcheck--1.1--1.2.sql amcheck--1.0--1.1.sql amcheck--1.0.sql +DATA = amcheck--1.3--1.4.sql amcheck--1.2--1.3.sql \ + amcheck--1.1--1.2.sql amcheck--1.0--1.1.sql \ + amcheck--1.0.sql PGFILEDESC = "amcheck - function for verifying relation integrity" -REGRESS = check check_btree check_heap +REGRESS = check check_btree check_heap check_gin TAP_TESTS = 1 diff --git a/contrib/amcheck/amcheck--1.3--1.4.sql b/contrib/amcheck/amcheck--1.3--1.4.sql new file mode 100644 index 00000000000..60d9dd1ab94 --- /dev/null +++ b/contrib/amcheck/amcheck--1.3--1.4.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 00000000000..e068b31b431 --- /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 ab50931f754..e67ace01c99 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 = '1.3' +default_version = '1.4' module_pathname = '$libdir/amcheck' relocatable = true diff --git a/contrib/amcheck/amcheck.h b/contrib/amcheck/amcheck.h new file mode 100644 index 00000000000..b19e6171778 --- /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 00000000000..35e3f0dc330 --- /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 00000000000..c81db477f11 --- /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 00000000000..65104f09ce6 --- /dev/null +++ b/contrib/amcheck/verify_gin.c @@ -0,0 +1,695 @@ +/*------------------------------------------------------------------------- + * + * 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; + ItemPointer parentkey; + 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 void 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; + stack->parentkey = NULL; + stack->blkno = 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->parentkey && ItemPointerCompare(stack->parentkey, &list[0]) < 0) + { + ereport(ERROR, + (errcode(ERRCODE_INDEX_CORRUPTED), + errmsg("index \"%s\": tid exceeds parent's high key in postingTree leaf on block %u", + RelationGetRelationName(rel), stack->blkno))); + } + } + else + { + + + /* + * Check that tuples in each page are properly ordered and + * consistent with parent high key + */ + maxoff = PageGetMaxOffsetNumber(page); + for (i = FirstOffsetNumber; i <= maxoff; i = OffsetNumberNext(i)) + { + PostingItem *posting_item = GinDataPageGetPostingItem(page, i); + + if (ItemPointerGetBlockNumberNoCheck(&posting_item->key) == 0 || + ItemPointerGetOffsetNumberNoCheck(&posting_item->key) == 0) + { + continue; + } + elog(INFO, "key block %u offset %u", ItemPointerGetBlockNumber(&posting_item->key), + ItemPointerGetOffsetNumber(&posting_item->key)); + + if (i != FirstOffsetNumber) + { + PostingItem *previous_posting_item = GinDataPageGetPostingItem(page, i - 1); + + if (ItemPointerCompare(&posting_item->key, &previous_posting_item->key) < 0) + { + + ereport(ERROR, + (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->parentkey && i == maxoff) + { + if (ItemPointerCompare(stack->parentkey, &posting_item->key) < 0) + { + ereport(ERROR, + (errcode(ERRCODE_INDEX_CORRUPTED), + errmsg("index \"%s\" has inconsistent records on page %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->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(ERROR, + (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 */ + check_index_page(rel, buffer, stack->blkno); + + /* + * 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(ERROR, + (errcode(ERRCODE_INDEX_CORRUPTED), + errmsg("index \"%s\": internal pages traversal encountered leaf page unexpectedly on block %u", + RelationGetRelationName(rel), stack->blkno))); + } + + /* + * 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(ERROR, + (errcode(ERRCODE_INDEX_CORRUPTED), + errmsg("index \"%s\" has inconsistent tuple sizes, block %u, offset %u", + RelationGetRelationName(rel), stack->blkno, i))); + + 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(ERROR, + (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); + } + + 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 void +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(ERROR, + (errcode(ERRCODE_INDEX_CORRUPTED), + errmsg("index \"%s\" contains unexpected zero page at block %u", + RelationGetRelationName(rel), + BufferGetBlockNumber(buf)), + errhint("Please REINDEX it."))); + + /* + * Additionally check that the special area looks sane. + */ + if (PageGetSpecialSize(page) != MAXALIGN(sizeof(GinPageOpaqueData))) + ereport(ERROR, + (errcode(ERRCODE_INDEX_CORRUPTED), + errmsg("index \"%s\" contains corrupted page at block %u", + RelationGetRelationName(rel), + BufferGetBlockNumber(buf)), + errhint("Please REINDEX it."))); +} + +static void +check_index_page(Relation rel, Buffer buffer, BlockNumber blockNo) +{ + Page page = BufferGetPage(buffer); + + gincheckpage(rel, buffer); + + if (GinPageIsDeleted(page)) + { + if (!GinPageIsLeaf(page)) + ereport(ERROR, + (errcode(ERRCODE_INDEX_CORRUPTED), + errmsg("index \"%s\" has deleted internal page %d", + RelationGetRelationName(rel), blockNo))); + if (PageGetMaxOffsetNumber(page) > InvalidOffsetNumber) + ereport(ERROR, + (errcode(ERRCODE_INDEX_CORRUPTED), + errmsg("index \"%s\" has deleted page %d with tuples", + RelationGetRelationName(rel), blockNo))); + } + else if (PageGetMaxOffsetNumber(page) > MaxIndexTuplesPerPage) + ereport(ERROR, + (errcode(ERRCODE_INDEX_CORRUPTED), + errmsg("index \"%s\" has page %d with exceeding count of tuples", + RelationGetRelationName(rel), blockNo))); +} + +/* + * 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 a2571d33ae6..ff3ce555f12 100644 --- a/doc/src/sgml/amcheck.sgml +++ b/doc/src/sgml/amcheck.sgml @@ -343,6 +343,25 @@ SET client_min_messages = DEBUG1; + + + + gin_index_parent_check(index regclass) returns void + + gin_index_parent_check + + + + + + gin_index_parent_check 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). + + + -- 2.30.2