database/postgres
1
0
Fork 0
mirror of https://github.com/postgres/postgres.git synced 2025-07-28 23:42:10 +03:00
Code Activity

Teach pageinspect about nbtree deduplication.

Browse Source 
Add a new bt_metap() column to display the metapage's allequalimage
field.  Also add three new columns to contrib/pageinspect's
bt_page_items() function:

* Add a boolean column ("dead") that displays the LP_DEAD bit value for
each non-pivot tuple.

* Add a TID column ("htid") that displays a single heap TID value for
each tuple.  This is the TID that is returned by BTreeTupleGetHeapTID(),
so comparable values are shown for pivot tuples, plain non-pivot tuples,
and posting list tuples.

* Add a TID array column ("tids") that displays TIDs from each tuple's
posting list, if any.  This works just like the "tids" column from
pageinspect's gin_leafpage_items() function.

No version bump for the pageinspect extension, since there hasn't been a
stable Postgres release since the last version bump (the last bump was
part of commit 58b4cb30).

Author: Peter Geoghegan
Discussion: https://postgr.es/m/CAH2-WzmSMmU2eNvY9+a4MNP+z02h6sa-uxZvN3un6jY02ZVBSw@mail.gmail.com
This commit is contained in:
Peter Geoghegan
2020-02-29 12:10:17 -08:00
parent 58c47ccfff
commit 93ee38eade
4 changed files with 273 additions and 53 deletions
Download Patch File Download Diff File Expand all files Collapse all files

146
contrib/pageinspect/btreefuncs.c
View File

@ -31,9 +31,11 @@
#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"
@ -45,6 +47,8 @@ PG_FUNCTION_INFO_V1(bt_page_stats);
#define IS_INDEX(r) ((r)->rd_rel->relkind == RELKIND_INDEX)
#define IS_BTREE(r) ((r)->rd_rel->relam == BTREE_AM_OID)
#define DatumGetItemPointer(X) ((ItemPointer) DatumGetPointer(X))
#define ItemPointerGetDatum(X) PointerGetDatum(X)
/* note: BlockNumber is unsigned, hence can't be negative */
#define CHECK_RELATION_BLOCK_RANGE(rel, blkno) { \
@ -243,6 +247,9 @@ struct user_args
{
Page page;
OffsetNumber offset;
bool leafpage;
bool rightmost;
TupleDesc tupd;
};
/*-------------------------------------------------------
@ -252,17 +259,25 @@ struct user_args
* ------------------------------------------------------
*/
static Datum
bt_page_print_tuples(FuncCallContext *fctx, Page page, OffsetNumber offset)
bt_page_print_tuples(FuncCallContext *fctx, struct user_args *uargs)
{
char *values[6];
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;
char *dump,
*datacstring;
char *ptr;
ItemPointer htid;
id = PageGetItemId(page, offset);
@ -272,18 +287,49 @@ bt_page_print_tuples(FuncCallContext *fctx, Page page, OffsetNumber offset)
itup = (IndexTuple) PageGetItem(page, id);
j = 0;
values[j++] = psprintf("%d", offset);
values[j++] = psprintf("(%u,%u)",
ItemPointerGetBlockNumberNoCheck(&itup->t_tid),
ItemPointerGetOffsetNumberNoCheck(&itup->t_tid));
values[j++] = psprintf("%d", (int) IndexTupleSize(itup));
values[j++] = psprintf("%c", IndexTupleHasNulls(itup) ? 't' : 'f');
values[j++] = psprintf("%c", IndexTupleHasVarwidths(itup) ? 't' : 'f');
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);
values[j] = dump;
datacstring = dump;
for (off = 0; off < dlen; off++)
{
if (off > 0)
@ -291,8 +337,62 @@ bt_page_print_tuples(FuncCallContext *fctx, Page page, OffsetNumber offset)
sprintf(dump, "%02x", *(ptr + off) & 0xff);
dump += 2;
}
values[j++] = CStringGetTextDatum(datacstring);
pfree(datacstring);
tuple = BuildTupleFromCStrings(fctx->attinmeta, values);
/*
* 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(tids_datum,
nposting,
TIDOID,
sizeof(ItemPointerData),
false, 's'));
pfree(tids_datum);
}
else
nulls[j++] = true;
/* Build and return the result tuple */
tuple = heap_form_tuple(uargs->tupd, values, nulls);
return HeapTupleGetDatum(tuple);
}
@ -378,12 +478,15 @@ bt_page_items(PG_FUNCTION_ARGS)
elog(NOTICE, "page is deleted");
fctx->max_calls = PageGetMaxOffsetNumber(uargs->page);
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);
fctx->attinmeta = TupleDescGetAttInMetadata(tupleDesc);
uargs->tupd = tupleDesc;
fctx->user_fctx = uargs;
@ -395,7 +498,7 @@ bt_page_items(PG_FUNCTION_ARGS)
if (fctx->call_cntr < fctx->max_calls)
{
result = bt_page_print_tuples(fctx, uargs->page, uargs->offset);
result = bt_page_print_tuples(fctx, uargs);
uargs->offset++;
SRF_RETURN_NEXT(fctx, result);
}
@ -463,12 +566,15 @@ bt_page_items_bytea(PG_FUNCTION_ARGS)
elog(NOTICE, "page is deleted");
fctx->max_calls = PageGetMaxOffsetNumber(uargs->page);
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);
fctx->attinmeta = TupleDescGetAttInMetadata(tupleDesc);
uargs->tupd = tupleDesc;
fctx->user_fctx = uargs;
@ -480,7 +586,7 @@ bt_page_items_bytea(PG_FUNCTION_ARGS)
if (fctx->call_cntr < fctx->max_calls)
{
result = bt_page_print_tuples(fctx, uargs->page, uargs->offset);
result = bt_page_print_tuples(fctx, uargs);
uargs->offset++;
SRF_RETURN_NEXT(fctx, result);
}
@ -510,7 +616,7 @@ bt_metap(PG_FUNCTION_ARGS)
BTMetaPageData *metad;
TupleDesc tupleDesc;
int j;
char *values[8];
char *values[9];
Buffer buffer;
Page page;
HeapTuple tuple;
@ -557,17 +663,21 @@ bt_metap(PG_FUNCTION_ARGS)
/*
* Get values of extended metadata if available, use default values
* otherwise.
* 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("%u", metad->btm_oldest_btpo_xact);
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),