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postgresql/contrib/pageinspect/btreefuncs.c

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/*
* contrib/pageinspect/btreefuncs.c
*
*
* btreefuncs.c
*
* Copyright (c) 2006 Satoshi Nagayasu <nagayasus@nttdata.co.jp>
*
* Permission to use, copy, modify, and distribute this software and
* its documentation for any purpose, without fee, and without a
* written agreement is hereby granted, provided that the above
* copyright notice and this paragraph and the following two
* paragraphs appear in all copies.
*
* IN NO EVENT SHALL THE AUTHOR BE LIABLE TO ANY PARTY FOR DIRECT,
* INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES, INCLUDING
* LOST PROFITS, ARISING OUT OF THE USE OF THIS SOFTWARE AND ITS
* DOCUMENTATION, EVEN IF THE UNIVERSITY OF CALIFORNIA HAS BEEN ADVISED
* OF THE POSSIBILITY OF SUCH DAMAGE.
*
* THE AUTHOR SPECIFICALLY DISCLAIMS ANY WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
* A PARTICULAR PURPOSE. THE SOFTWARE PROVIDED HEREUNDER IS ON AN "AS
* IS" BASIS, AND THE AUTHOR HAS NO OBLIGATIONS TO PROVIDE MAINTENANCE,
* SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS.
*/
#include "postgres.h"
#include "access/nbtree.h"
#include "access/relation.h"
#include "catalog/namespace.h"
#include "catalog/pg_am.h"
#include "catalog/pg_type.h"
#include "funcapi.h"
#include "miscadmin.h"
#include "pageinspect.h"
#include "utils/array.h"
#include "utils/builtins.h"
#include "utils/rel.h"
#include "utils/varlena.h"
PG_FUNCTION_INFO_V1(bt_metap);
PG_FUNCTION_INFO_V1(bt_page_items_1_9);
PG_FUNCTION_INFO_V1(bt_page_items);
PG_FUNCTION_INFO_V1(bt_page_items_bytea);
PG_FUNCTION_INFO_V1(bt_page_stats_1_9);
PG_FUNCTION_INFO_V1(bt_page_stats);
PG_FUNCTION_INFO_V1(bt_multi_page_stats);
#define IS_INDEX(r) ((r)->rd_rel->relkind == RELKIND_INDEX)
#define IS_BTREE(r) ((r)->rd_rel->relam == BTREE_AM_OID)
/* ------------------------------------------------
* structure for single btree page statistics
* ------------------------------------------------
*/
typedef struct BTPageStat
{
uint32 blkno;
uint32 live_items;
uint32 dead_items;
uint32 page_size;
uint32 max_avail;
uint32 free_size;
uint32 avg_item_size;
char type;
/* opaque data */
BlockNumber btpo_prev;
BlockNumber btpo_next;
uint32 btpo_level;
uint16 btpo_flags;
BTCycleId btpo_cycleid;
} BTPageStat;
/*
* cross-call data structure for SRF for page stats
*/
typedef struct ua_page_stats
{
Oid relid;
int64 blkno;
int64 blk_count;
bool allpages;
} ua_page_stats;
/*
* cross-call data structure for SRF for page items
*/
typedef struct ua_page_items
{
Page page;
OffsetNumber offset;
bool leafpage;
bool rightmost;
TupleDesc tupd;
} ua_page_items;
/* -------------------------------------------------
* GetBTPageStatistics()
*
* Collect statistics of single b-tree page
* -------------------------------------------------
*/
static void
GetBTPageStatistics(BlockNumber blkno, Buffer buffer, BTPageStat *stat)
{
Page page = BufferGetPage(buffer);
PageHeader phdr = (PageHeader) page;
OffsetNumber maxoff = PageGetMaxOffsetNumber(page);
BTPageOpaque opaque = BTPageGetOpaque(page);
int item_size = 0;
int off;
stat->blkno = blkno;
stat->max_avail = BLCKSZ - (BLCKSZ - phdr->pd_special + SizeOfPageHeaderData);
stat->dead_items = stat->live_items = 0;
stat->page_size = PageGetPageSize(page);
/* page type (flags) */
if (P_ISDELETED(opaque))
{
/* We divide deleted pages into leaf ('d') or internal ('D') */
if (P_ISLEAF(opaque) || !P_HAS_FULLXID(opaque))
stat->type = 'd';
else
stat->type = 'D';
/*
* Report safexid in a deleted page.
*
* Handle pg_upgrade'd deleted pages that used the previous safexid
* representation in btpo_level field (this used to be a union type
* called "bpto").
*/
if (P_HAS_FULLXID(opaque))
{
FullTransactionId safexid = BTPageGetDeleteXid(page);
elog(DEBUG2, "deleted page from block %u has safexid %u:%u",
blkno, EpochFromFullTransactionId(safexid),
XidFromFullTransactionId(safexid));
}
else
elog(DEBUG2, "deleted page from block %u has safexid %u",
blkno, opaque->btpo_level);
/* Don't interpret BTDeletedPageData as index tuples */
maxoff = InvalidOffsetNumber;
}
else if (P_IGNORE(opaque))
stat->type = 'e';
else if (P_ISLEAF(opaque))
stat->type = 'l';
else if (P_ISROOT(opaque))
stat->type = 'r';
else
stat->type = 'i';
/* btpage opaque data */
stat->btpo_prev = opaque->btpo_prev;
stat->btpo_next = opaque->btpo_next;
stat->btpo_level = opaque->btpo_level;
stat->btpo_flags = opaque->btpo_flags;
stat->btpo_cycleid = opaque->btpo_cycleid;
/* count live and dead tuples, and free space */
for (off = FirstOffsetNumber; off <= maxoff; off++)
{
IndexTuple itup;
ItemId id = PageGetItemId(page, off);
itup = (IndexTuple) PageGetItem(page, id);
item_size += IndexTupleSize(itup);
if (!ItemIdIsDead(id))
stat->live_items++;
else
stat->dead_items++;
}
stat->free_size = PageGetFreeSpace(page);
if ((stat->live_items + stat->dead_items) > 0)
stat->avg_item_size = item_size / (stat->live_items + stat->dead_items);
else
stat->avg_item_size = 0;
}
/* -----------------------------------------------
* check_relation_block_range()
*
* Verify that a block number (given as int64) is valid for the relation.
* -----------------------------------------------
*/
static void
check_relation_block_range(Relation rel, int64 blkno)
{
/* Ensure we can cast to BlockNumber */
if (blkno < 0 || blkno > MaxBlockNumber)
ereport(ERROR,
(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
errmsg("invalid block number %lld",
(long long) blkno)));
if ((BlockNumber) (blkno) >= RelationGetNumberOfBlocks(rel))
ereport(ERROR,
(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
errmsg("block number %lld is out of range",
(long long) blkno)));
}
/* -----------------------------------------------
* bt_index_block_validate()
*
* Validate index type is btree and block number
* is valid (and not the metapage).
* -----------------------------------------------
*/
static void
bt_index_block_validate(Relation rel, int64 blkno)
{
if (!IS_INDEX(rel) || !IS_BTREE(rel))
ereport(ERROR,
(errcode(ERRCODE_WRONG_OBJECT_TYPE),
errmsg("\"%s\" is not a %s index",
RelationGetRelationName(rel), "btree")));
/*
* Reject attempts to read non-local temporary relations; we would be
* likely to get wrong data since we have no visibility into the owning
* session's local buffers.
*/
if (RELATION_IS_OTHER_TEMP(rel))
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("cannot access temporary tables of other sessions")));
if (blkno == 0)
ereport(ERROR,
(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
errmsg("block 0 is a meta page")));
check_relation_block_range(rel, blkno);
}
/* -----------------------------------------------
* bt_page_stats()
*
* Usage: SELECT * FROM bt_page_stats('t1_pkey', 1);
* Arguments are index relation name and block number
* -----------------------------------------------
*/
static Datum
bt_page_stats_internal(PG_FUNCTION_ARGS, enum pageinspect_version ext_version)
{
text *relname = PG_GETARG_TEXT_PP(0);
int64 blkno = (ext_version == PAGEINSPECT_V1_8 ? PG_GETARG_UINT32(1) : PG_GETARG_INT64(1));
Buffer buffer;
Relation rel;
RangeVar *relrv;
Datum result;
HeapTuple tuple;
TupleDesc tupleDesc;
int j;
char *values[11];
BTPageStat stat;
if (!superuser())
ereport(ERROR,
(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
errmsg("must be superuser to use pageinspect functions")));
relrv = makeRangeVarFromNameList(textToQualifiedNameList(relname));
rel = relation_openrv(relrv, AccessShareLock);
bt_index_block_validate(rel, blkno);
buffer = ReadBuffer(rel, blkno);
LockBuffer(buffer, BUFFER_LOCK_SHARE);
/* keep compiler quiet */
stat.btpo_prev = stat.btpo_next = InvalidBlockNumber;
stat.btpo_flags = stat.free_size = stat.avg_item_size = 0;
GetBTPageStatistics(blkno, buffer, &stat);
UnlockReleaseBuffer(buffer);
relation_close(rel, AccessShareLock);
/* Build a tuple descriptor for our result type */
if (get_call_result_type(fcinfo, NULL, &tupleDesc) != TYPEFUNC_COMPOSITE)
elog(ERROR, "return type must be a row type");
j = 0;
values[j++] = psprintf("%u", stat.blkno);
values[j++] = psprintf("%c", stat.type);
values[j++] = psprintf("%u", stat.live_items);
values[j++] = psprintf("%u", stat.dead_items);
values[j++] = psprintf("%u", stat.avg_item_size);
values[j++] = psprintf("%u", stat.page_size);
values[j++] = psprintf("%u", stat.free_size);
values[j++] = psprintf("%u", stat.btpo_prev);
values[j++] = psprintf("%u", stat.btpo_next);
values[j++] = psprintf("%u", stat.btpo_level);
values[j++] = psprintf("%d", stat.btpo_flags);
tuple = BuildTupleFromCStrings(TupleDescGetAttInMetadata(tupleDesc),
values);
result = HeapTupleGetDatum(tuple);
PG_RETURN_DATUM(result);
}
Datum
bt_page_stats_1_9(PG_FUNCTION_ARGS)
{
return bt_page_stats_internal(fcinfo, PAGEINSPECT_V1_9);
}
/* entry point for old extension version */
Datum
bt_page_stats(PG_FUNCTION_ARGS)
{
return bt_page_stats_internal(fcinfo, PAGEINSPECT_V1_8);
}
/* -----------------------------------------------
* bt_multi_page_stats()
*
* Usage: SELECT * FROM bt_page_stats('t1_pkey', 1, 2);
* Arguments are index relation name, first block number, number of blocks
* (but number of blocks can be negative to mean "read all the rest")
* -----------------------------------------------
*/
Datum
bt_multi_page_stats(PG_FUNCTION_ARGS)
{
Relation rel;
ua_page_stats *uargs;
FuncCallContext *fctx;
MemoryContext mctx;
if (!superuser())
ereport(ERROR,
(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
errmsg("must be superuser to use pageinspect functions")));
if (SRF_IS_FIRSTCALL())
{
text *relname = PG_GETARG_TEXT_PP(0);
int64 blkno = PG_GETARG_INT64(1);
int64 blk_count = PG_GETARG_INT64(2);
RangeVar *relrv;
fctx = SRF_FIRSTCALL_INIT();
relrv = makeRangeVarFromNameList(textToQualifiedNameList(relname));
rel = relation_openrv(relrv, AccessShareLock);
/* Check that rel is a valid btree index and 1st block number is OK */
bt_index_block_validate(rel, blkno);
/*
* Check if upper bound of the specified range is valid. If only one
* page is requested, skip as we've already validated the page. (Also,
* it's important to skip this if blk_count is negative.)
*/
if (blk_count > 1)
check_relation_block_range(rel, blkno + blk_count - 1);
/* Save arguments for reuse */
mctx = MemoryContextSwitchTo(fctx->multi_call_memory_ctx);
uargs = palloc(sizeof(ua_page_stats));
uargs->relid = RelationGetRelid(rel);
uargs->blkno = blkno;
uargs->blk_count = blk_count;
uargs->allpages = (blk_count < 0);
fctx->user_fctx = uargs;
MemoryContextSwitchTo(mctx);
/*
* To avoid possibly leaking a relcache reference if the SRF isn't run
* to completion, we close and re-open the index rel each time
* through, using the index's OID for re-opens to ensure we get the
* same rel. Keep the AccessShareLock though, to ensure it doesn't go
* away underneath us.
*/
relation_close(rel, NoLock);
}
fctx = SRF_PERCALL_SETUP();
uargs = fctx->user_fctx;
/* We should have lock already */
rel = relation_open(uargs->relid, NoLock);
/* In all-pages mode, recheck the index length each time */
if (uargs->allpages)
uargs->blk_count = RelationGetNumberOfBlocks(rel) - uargs->blkno;
if (uargs->blk_count > 0)
{
/* We need to fetch next block statistics */
Buffer buffer;
Datum result;
HeapTuple tuple;
int j;
char *values[11];
BTPageStat stat;
TupleDesc tupleDesc;
buffer = ReadBuffer(rel, uargs->blkno);
LockBuffer(buffer, BUFFER_LOCK_SHARE);
/* keep compiler quiet */
stat.btpo_prev = stat.btpo_next = InvalidBlockNumber;
stat.btpo_flags = stat.free_size = stat.avg_item_size = 0;
GetBTPageStatistics(uargs->blkno, buffer, &stat);
UnlockReleaseBuffer(buffer);
relation_close(rel, NoLock);
/* Build a tuple descriptor for our result type */
if (get_call_result_type(fcinfo, NULL, &tupleDesc) != TYPEFUNC_COMPOSITE)
elog(ERROR, "return type must be a row type");
j = 0;
values[j++] = psprintf("%u", stat.blkno);
values[j++] = psprintf("%c", stat.type);
values[j++] = psprintf("%u", stat.live_items);
values[j++] = psprintf("%u", stat.dead_items);
values[j++] = psprintf("%u", stat.avg_item_size);
values[j++] = psprintf("%u", stat.page_size);
values[j++] = psprintf("%u", stat.free_size);
values[j++] = psprintf("%u", stat.btpo_prev);
values[j++] = psprintf("%u", stat.btpo_next);
values[j++] = psprintf("%u", stat.btpo_level);
values[j++] = psprintf("%d", stat.btpo_flags);
/* Construct tuple to be returned */
tuple = BuildTupleFromCStrings(TupleDescGetAttInMetadata(tupleDesc),
values);
result = HeapTupleGetDatum(tuple);
/*
* Move to the next block number and decrement the number of blocks
* still to be fetched
*/
uargs->blkno++;
uargs->blk_count--;
SRF_RETURN_NEXT(fctx, result);
}
/* Done, so finally we can release the index lock */
relation_close(rel, AccessShareLock);
SRF_RETURN_DONE(fctx);
}
/*-------------------------------------------------------
* bt_page_print_tuples()
*
* Form a tuple describing index tuple at a given offset
* ------------------------------------------------------
*/
static Datum
bt_page_print_tuples(ua_page_items *uargs)
{
Page page = uargs->page;
OffsetNumber offset = uargs->offset;
bool leafpage = uargs->leafpage;
bool rightmost = uargs->rightmost;
bool ispivottuple;
Datum values[9];
bool nulls[9];
HeapTuple tuple;
ItemId id;
IndexTuple itup;
int j;
int off;
int dlen;
char *dump,
*datacstring;
char *ptr;
ItemPointer htid;
id = PageGetItemId(page, offset);
if (!ItemIdIsValid(id))
elog(ERROR, "invalid ItemId");
itup = (IndexTuple) PageGetItem(page, id);
j = 0;
memset(nulls, 0, sizeof(nulls));
values[j++] = DatumGetInt16(offset);
values[j++] = ItemPointerGetDatum(&itup->t_tid);
values[j++] = Int32GetDatum((int) IndexTupleSize(itup));
values[j++] = BoolGetDatum(IndexTupleHasNulls(itup));
values[j++] = BoolGetDatum(IndexTupleHasVarwidths(itup));
ptr = (char *) itup + IndexInfoFindDataOffset(itup->t_info);
dlen = IndexTupleSize(itup) - IndexInfoFindDataOffset(itup->t_info);
/*
* Make sure that "data" column does not include posting list or pivot
* tuple representation of heap TID(s).
*
* Note: BTreeTupleIsPivot() won't work reliably on !heapkeyspace indexes
* (those built before BTREE_VERSION 4), but we have no way of determining
* if this page came from a !heapkeyspace index. We may only have a bytea
* nbtree page image to go on, so in general there is no metapage that we
* can check.
*
* That's okay here because BTreeTupleIsPivot() can only return false for
* a !heapkeyspace pivot, never true for a !heapkeyspace non-pivot. Since
* heap TID isn't part of the keyspace in a !heapkeyspace index anyway,
* there cannot possibly be a pivot tuple heap TID representation that we
* fail to make an adjustment for. A !heapkeyspace index can have
* BTreeTupleIsPivot() return true (due to things like suffix truncation
* for INCLUDE indexes in Postgres v11), but when that happens
* BTreeTupleGetHeapTID() can be trusted to work reliably (i.e. return
* NULL).
*
* Note: BTreeTupleIsPosting() always works reliably, even with
* !heapkeyspace indexes.
*/
if (BTreeTupleIsPosting(itup))
dlen -= IndexTupleSize(itup) - BTreeTupleGetPostingOffset(itup);
else if (BTreeTupleIsPivot(itup) && BTreeTupleGetHeapTID(itup) != NULL)
dlen -= MAXALIGN(sizeof(ItemPointerData));
if (dlen < 0 || dlen > INDEX_SIZE_MASK)
elog(ERROR, "invalid tuple length %d for tuple at offset number %u",
dlen, offset);
dump = palloc0(dlen * 3 + 1);
datacstring = dump;
for (off = 0; off < dlen; off++)
{
if (off > 0)
*dump++ = ' ';
sprintf(dump, "%02x", *(ptr + off) & 0xff);
dump += 2;
}
values[j++] = CStringGetTextDatum(datacstring);
pfree(datacstring);
/*
* We need to work around the BTreeTupleIsPivot() !heapkeyspace limitation
* again. Deduce whether or not tuple must be a pivot tuple based on
* whether or not the page is a leaf page, as well as the page offset
* number of the tuple.
*/
ispivottuple = (!leafpage || (!rightmost && offset == P_HIKEY));
/* LP_DEAD bit can never be set for pivot tuples, so show a NULL there */
if (!ispivottuple)
values[j++] = BoolGetDatum(ItemIdIsDead(id));
else
{
Assert(!ItemIdIsDead(id));
nulls[j++] = true;
}
htid = BTreeTupleGetHeapTID(itup);
if (ispivottuple && !BTreeTupleIsPivot(itup))
{
/* Don't show bogus heap TID in !heapkeyspace pivot tuple */
htid = NULL;
}
if (htid)
values[j++] = ItemPointerGetDatum(htid);
else
nulls[j++] = true;
if (BTreeTupleIsPosting(itup))
{
/* Build an array of item pointers */
ItemPointer tids;
Datum *tids_datum;
int nposting;
tids = BTreeTupleGetPosting(itup);
nposting = BTreeTupleGetNPosting(itup);
tids_datum = (Datum *) palloc(nposting * sizeof(Datum));
for (int i = 0; i < nposting; i++)
tids_datum[i] = ItemPointerGetDatum(&tids[i]);
values[j++] = PointerGetDatum(construct_array_builtin(tids_datum, nposting, TIDOID));
pfree(tids_datum);
}
else
nulls[j++] = true;
/* Build and return the result tuple */
tuple = heap_form_tuple(uargs->tupd, values, nulls);
return HeapTupleGetDatum(tuple);
}
/*-------------------------------------------------------
* bt_page_items()
*
* Get IndexTupleData set in a btree page
*
* Usage: SELECT * FROM bt_page_items('t1_pkey', 1);
*-------------------------------------------------------
*/
static Datum
bt_page_items_internal(PG_FUNCTION_ARGS, enum pageinspect_version ext_version)
{
text *relname = PG_GETARG_TEXT_PP(0);
int64 blkno = (ext_version == PAGEINSPECT_V1_8 ? PG_GETARG_UINT32(1) : PG_GETARG_INT64(1));
Datum result;
FuncCallContext *fctx;
MemoryContext mctx;
ua_page_items *uargs;
if (!superuser())
ereport(ERROR,
(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
errmsg("must be superuser to use pageinspect functions")));
if (SRF_IS_FIRSTCALL())
{
RangeVar *relrv;
Relation rel;
Buffer buffer;
BTPageOpaque opaque;
TupleDesc tupleDesc;
fctx = SRF_FIRSTCALL_INIT();
relrv = makeRangeVarFromNameList(textToQualifiedNameList(relname));
rel = relation_openrv(relrv, AccessShareLock);
bt_index_block_validate(rel, blkno);
buffer = ReadBuffer(rel, blkno);
LockBuffer(buffer, BUFFER_LOCK_SHARE);
/*
* We copy the page into local storage to avoid holding pin on the
* buffer longer than we must, and possibly failing to release it at
* all if the calling query doesn't fetch all rows.
*/
mctx = MemoryContextSwitchTo(fctx->multi_call_memory_ctx);
uargs = palloc(sizeof(ua_page_items));
uargs->page = palloc(BLCKSZ);
memcpy(uargs->page, BufferGetPage(buffer), BLCKSZ);
UnlockReleaseBuffer(buffer);
relation_close(rel, AccessShareLock);
uargs->offset = FirstOffsetNumber;
opaque = BTPageGetOpaque(uargs->page);
if (!P_ISDELETED(opaque))
fctx->max_calls = PageGetMaxOffsetNumber(uargs->page);
else
{
/* Don't interpret BTDeletedPageData as index tuples */
elog(NOTICE, "page from block " INT64_FORMAT " is deleted", blkno);
fctx->max_calls = 0;
}
uargs->leafpage = P_ISLEAF(opaque);
uargs->rightmost = P_RIGHTMOST(opaque);
/* Build a tuple descriptor for our result type */
if (get_call_result_type(fcinfo, NULL, &tupleDesc) != TYPEFUNC_COMPOSITE)
elog(ERROR, "return type must be a row type");
tupleDesc = BlessTupleDesc(tupleDesc);
uargs->tupd = tupleDesc;
fctx->user_fctx = uargs;
MemoryContextSwitchTo(mctx);
}
fctx = SRF_PERCALL_SETUP();
uargs = fctx->user_fctx;
if (fctx->call_cntr < fctx->max_calls)
{
result = bt_page_print_tuples(uargs);
uargs->offset++;
SRF_RETURN_NEXT(fctx, result);
}
SRF_RETURN_DONE(fctx);
}
Datum
bt_page_items_1_9(PG_FUNCTION_ARGS)
{
return bt_page_items_internal(fcinfo, PAGEINSPECT_V1_9);
}
/* entry point for old extension version */
Datum
bt_page_items(PG_FUNCTION_ARGS)
{
return bt_page_items_internal(fcinfo, PAGEINSPECT_V1_8);
}
/*-------------------------------------------------------
* bt_page_items_bytea()
*
* Get IndexTupleData set in a btree page
*
* Usage: SELECT * FROM bt_page_items(get_raw_page('t1_pkey', 1));
*-------------------------------------------------------
*/
Datum
bt_page_items_bytea(PG_FUNCTION_ARGS)
{
bytea *raw_page = PG_GETARG_BYTEA_P(0);
Datum result;
FuncCallContext *fctx;
ua_page_items *uargs;
if (!superuser())
ereport(ERROR,
(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
errmsg("must be superuser to use raw page functions")));
if (SRF_IS_FIRSTCALL())
{
BTPageOpaque opaque;
MemoryContext mctx;
TupleDesc tupleDesc;
fctx = SRF_FIRSTCALL_INIT();
mctx = MemoryContextSwitchTo(fctx->multi_call_memory_ctx);
uargs = palloc(sizeof(ua_page_items));
uargs->page = get_page_from_raw(raw_page);
if (PageIsNew(uargs->page))
{
MemoryContextSwitchTo(mctx);
PG_RETURN_NULL();
}
uargs->offset = FirstOffsetNumber;
/* verify the special space has the expected size */
if (PageGetSpecialSize(uargs->page) != MAXALIGN(sizeof(BTPageOpaqueData)))
ereport(ERROR,
(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
errmsg("input page is not a valid %s page", "btree"),
errdetail("Expected special size %d, got %d.",
(int) MAXALIGN(sizeof(BTPageOpaqueData)),
(int) PageGetSpecialSize(uargs->page))));
opaque = BTPageGetOpaque(uargs->page);
if (P_ISMETA(opaque))
ereport(ERROR,
(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
errmsg("block is a meta page")));
if (P_ISLEAF(opaque) && opaque->btpo_level != 0)
ereport(ERROR,
(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
errmsg("block is not a valid btree leaf page")));
if (P_ISDELETED(opaque))
elog(NOTICE, "page is deleted");
if (!P_ISDELETED(opaque))
fctx->max_calls = PageGetMaxOffsetNumber(uargs->page);
else
{
/* Don't interpret BTDeletedPageData as index tuples */
elog(NOTICE, "page from block is deleted");
fctx->max_calls = 0;
}
uargs->leafpage = P_ISLEAF(opaque);
uargs->rightmost = P_RIGHTMOST(opaque);
/* Build a tuple descriptor for our result type */
if (get_call_result_type(fcinfo, NULL, &tupleDesc) != TYPEFUNC_COMPOSITE)
elog(ERROR, "return type must be a row type");
tupleDesc = BlessTupleDesc(tupleDesc);
uargs->tupd = tupleDesc;
fctx->user_fctx = uargs;
MemoryContextSwitchTo(mctx);
}
fctx = SRF_PERCALL_SETUP();
uargs = fctx->user_fctx;
if (fctx->call_cntr < fctx->max_calls)
{
result = bt_page_print_tuples(uargs);
uargs->offset++;
SRF_RETURN_NEXT(fctx, result);
}
SRF_RETURN_DONE(fctx);
}
/* Number of output arguments (columns) for bt_metap() */
#define BT_METAP_COLS_V1_8 9
/* ------------------------------------------------
* bt_metap()
*
* Get a btree's meta-page information
*
* Usage: SELECT * FROM bt_metap('t1_pkey')
* ------------------------------------------------
*/
Datum
bt_metap(PG_FUNCTION_ARGS)
{
text *relname = PG_GETARG_TEXT_PP(0);
Datum result;
Relation rel;
RangeVar *relrv;
BTMetaPageData *metad;
TupleDesc tupleDesc;
int j;
char *values[9];
Buffer buffer;
Page page;
HeapTuple tuple;
if (!superuser())
ereport(ERROR,
(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
errmsg("must be superuser to use pageinspect functions")));
relrv = makeRangeVarFromNameList(textToQualifiedNameList(relname));
rel = relation_openrv(relrv, AccessShareLock);
if (!IS_INDEX(rel) || !IS_BTREE(rel))
ereport(ERROR,
(errcode(ERRCODE_WRONG_OBJECT_TYPE),
errmsg("\"%s\" is not a %s index",
RelationGetRelationName(rel), "btree")));
/*
* Reject attempts to read non-local temporary relations; we would be
* likely to get wrong data since we have no visibility into the owning
* session's local buffers.
*/
if (RELATION_IS_OTHER_TEMP(rel))
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("cannot access temporary tables of other sessions")));
buffer = ReadBuffer(rel, 0);
LockBuffer(buffer, BUFFER_LOCK_SHARE);
page = BufferGetPage(buffer);
metad = BTPageGetMeta(page);
/* Build a tuple descriptor for our result type */
if (get_call_result_type(fcinfo, NULL, &tupleDesc) != TYPEFUNC_COMPOSITE)
elog(ERROR, "return type must be a row type");
/*
* We need a kluge here to detect API versions prior to 1.8. Earlier
* versions incorrectly used int4 for certain columns.
*
* There is no way to reliably avoid the problems created by the old
* function definition at this point, so insist that the user update the
* extension.
*/
if (tupleDesc->natts < BT_METAP_COLS_V1_8)
ereport(ERROR,
(errcode(ERRCODE_INVALID_FUNCTION_DEFINITION),
errmsg("function has wrong number of declared columns"),
errhint("To resolve the problem, update the \"pageinspect\" extension to the latest version.")));
j = 0;
values[j++] = psprintf("%d", metad->btm_magic);
values[j++] = psprintf("%d", metad->btm_version);
values[j++] = psprintf(INT64_FORMAT, (int64) metad->btm_root);
values[j++] = psprintf(INT64_FORMAT, (int64) metad->btm_level);
values[j++] = psprintf(INT64_FORMAT, (int64) metad->btm_fastroot);
values[j++] = psprintf(INT64_FORMAT, (int64) metad->btm_fastlevel);
/*
* Get values of extended metadata if available, use default values
* otherwise. Note that we rely on the assumption that btm_allequalimage
* is initialized to zero with indexes that were built on versions prior
* to Postgres 13 (just like _bt_metaversion()).
*/
if (metad->btm_version >= BTREE_NOVAC_VERSION)
{
values[j++] = psprintf(INT64_FORMAT,
(int64) metad->btm_last_cleanup_num_delpages);
values[j++] = psprintf("%f", metad->btm_last_cleanup_num_heap_tuples);
values[j++] = metad->btm_allequalimage ? "t" : "f";
}
else
{
values[j++] = "0";
values[j++] = "-1";
values[j++] = "f";
}
tuple = BuildTupleFromCStrings(TupleDescGetAttInMetadata(tupleDesc),
values);
result = HeapTupleGetDatum(tuple);
UnlockReleaseBuffer(buffer);
relation_close(rel, AccessShareLock);
PG_RETURN_DATUM(result);
}
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