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Getting from get_raw_page() an all-zero page is considered as a valid case by the buffer manager and it can happen for example when finding a corrupted page with zero_damaged_pages enabled (using zero_damaged_pages to look at corrupted pages happens), or after a crash when a relation file is extended before any WAL for its new data is generated (before a vacuum or autovacuum job comes in to do some cleanup). However, all the functions of pageinspect, as of the index AMs (except hash that has its own idea of new pages), heap, the FSM or the page header have never worked with all-zero pages, causing various crashes when going through the page internals. This commit changes all the pageinspect functions to be compliant with all-zero pages, where the choice is made to return NULL or no rows for SRFs when finding a new page. get_raw_page() still works the same way, returning a batch of zeros in the bytea of the page retrieved. A hard error could be used but NULL, while more invasive, is useful when scanning relation files in full to get a batch of results for a single relation in one query. Tests are added for all the code paths impacted. Reported-by: Daria Lepikhova Author: Michael Paquier Discussion: https://postgr.es/m/561e187b-3549-c8d5-03f5-525c14e65bd0@postgrespro.ru Backpatch-through: 10
338 lines
9.7 KiB
C
338 lines
9.7 KiB
C
/*
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* gistfuncs.c
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* Functions to investigate the content of GiST indexes
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*
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* Copyright (c) 2014-2021, PostgreSQL Global Development Group
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*
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* IDENTIFICATION
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* contrib/pageinspect/gistfuncs.c
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*/
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#include "postgres.h"
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#include "access/gist.h"
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#include "access/gist_private.h"
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#include "access/htup.h"
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#include "access/relation.h"
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#include "catalog/namespace.h"
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#include "catalog/pg_am_d.h"
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#include "funcapi.h"
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#include "miscadmin.h"
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#include "pageinspect.h"
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#include "storage/itemptr.h"
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#include "utils/array.h"
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#include "utils/builtins.h"
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#include "utils/rel.h"
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#include "utils/pg_lsn.h"
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#include "utils/varlena.h"
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PG_FUNCTION_INFO_V1(gist_page_opaque_info);
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PG_FUNCTION_INFO_V1(gist_page_items);
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PG_FUNCTION_INFO_V1(gist_page_items_bytea);
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#define IS_GIST(r) ((r)->rd_rel->relam == GIST_AM_OID)
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#define ItemPointerGetDatum(X) PointerGetDatum(X)
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Datum
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gist_page_opaque_info(PG_FUNCTION_ARGS)
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{
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bytea *raw_page = PG_GETARG_BYTEA_P(0);
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TupleDesc tupdesc;
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Page page;
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GISTPageOpaque opaq;
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HeapTuple resultTuple;
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Datum values[4];
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bool nulls[4];
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Datum flags[16];
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int nflags = 0;
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uint16 flagbits;
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if (!superuser())
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ereport(ERROR,
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(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
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errmsg("must be superuser to use raw page functions")));
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page = get_page_from_raw(raw_page);
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if (PageIsNew(page))
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PG_RETURN_NULL();
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/* verify the special space has the expected size */
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if (PageGetSpecialSize(page) != MAXALIGN(sizeof(GISTPageOpaqueData)))
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ereport(ERROR,
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(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
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errmsg("input page is not a valid %s page", "GiST"),
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errdetail("Expected special size %d, got %d.",
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(int) MAXALIGN(sizeof(GISTPageOpaqueData)),
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(int) PageGetSpecialSize(page))));
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opaq = (GISTPageOpaque) PageGetSpecialPointer(page);
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if (opaq->gist_page_id != GIST_PAGE_ID)
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ereport(ERROR,
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(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
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errmsg("input page is not a valid %s page", "GiST"),
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errdetail("Expected %08x, got %08x.",
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GIST_PAGE_ID,
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opaq->gist_page_id)));
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/* Build a tuple descriptor for our result type */
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if (get_call_result_type(fcinfo, NULL, &tupdesc) != TYPEFUNC_COMPOSITE)
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elog(ERROR, "return type must be a row type");
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/* Convert the flags bitmask to an array of human-readable names */
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flagbits = opaq->flags;
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if (flagbits & F_LEAF)
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flags[nflags++] = CStringGetTextDatum("leaf");
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if (flagbits & F_DELETED)
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flags[nflags++] = CStringGetTextDatum("deleted");
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if (flagbits & F_TUPLES_DELETED)
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flags[nflags++] = CStringGetTextDatum("tuples_deleted");
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if (flagbits & F_FOLLOW_RIGHT)
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flags[nflags++] = CStringGetTextDatum("follow_right");
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if (flagbits & F_HAS_GARBAGE)
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flags[nflags++] = CStringGetTextDatum("has_garbage");
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flagbits &= ~(F_LEAF | F_DELETED | F_TUPLES_DELETED | F_FOLLOW_RIGHT | F_HAS_GARBAGE);
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if (flagbits)
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{
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/* any flags we don't recognize are printed in hex */
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flags[nflags++] = DirectFunctionCall1(to_hex32, Int32GetDatum(flagbits));
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}
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memset(nulls, 0, sizeof(nulls));
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values[0] = LSNGetDatum(PageGetLSN(page));
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values[1] = LSNGetDatum(GistPageGetNSN(page));
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values[2] = Int64GetDatum(opaq->rightlink);
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values[3] = PointerGetDatum(construct_array(flags, nflags,
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TEXTOID,
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-1, false, TYPALIGN_INT));
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/* Build and return the result tuple. */
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resultTuple = heap_form_tuple(tupdesc, values, nulls);
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return HeapTupleGetDatum(resultTuple);
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}
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Datum
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gist_page_items_bytea(PG_FUNCTION_ARGS)
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{
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bytea *raw_page = PG_GETARG_BYTEA_P(0);
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ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo;
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bool randomAccess;
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TupleDesc tupdesc;
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Tuplestorestate *tupstore;
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MemoryContext oldcontext;
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Page page;
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GISTPageOpaque opaq;
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OffsetNumber offset;
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OffsetNumber maxoff = InvalidOffsetNumber;
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if (!superuser())
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ereport(ERROR,
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(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
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errmsg("must be superuser to use raw page functions")));
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/* check to see if caller supports us returning a tuplestore */
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if (rsinfo == NULL || !IsA(rsinfo, ReturnSetInfo))
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ereport(ERROR,
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(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
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errmsg("set-valued function called in context that cannot accept a set")));
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if (!(rsinfo->allowedModes & SFRM_Materialize))
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ereport(ERROR,
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(errcode(ERRCODE_SYNTAX_ERROR),
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errmsg("materialize mode required, but it is not allowed in this context")));
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/* The tupdesc and tuplestore must be created in ecxt_per_query_memory */
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oldcontext = MemoryContextSwitchTo(rsinfo->econtext->ecxt_per_query_memory);
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if (get_call_result_type(fcinfo, NULL, &tupdesc) != TYPEFUNC_COMPOSITE)
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elog(ERROR, "return type must be a row type");
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randomAccess = (rsinfo->allowedModes & SFRM_Materialize_Random) != 0;
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tupstore = tuplestore_begin_heap(randomAccess, false, work_mem);
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rsinfo->returnMode = SFRM_Materialize;
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rsinfo->setResult = tupstore;
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rsinfo->setDesc = tupdesc;
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MemoryContextSwitchTo(oldcontext);
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page = get_page_from_raw(raw_page);
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if (PageIsNew(page))
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PG_RETURN_NULL();
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/* verify the special space has the expected size */
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if (PageGetSpecialSize(page) != MAXALIGN(sizeof(GISTPageOpaqueData)))
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ereport(ERROR,
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(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
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errmsg("input page is not a valid %s page", "GiST"),
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errdetail("Expected special size %d, got %d.",
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(int) MAXALIGN(sizeof(GISTPageOpaqueData)),
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(int) PageGetSpecialSize(page))));
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opaq = (GISTPageOpaque) PageGetSpecialPointer(page);
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if (opaq->gist_page_id != GIST_PAGE_ID)
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ereport(ERROR,
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(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
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errmsg("input page is not a valid %s page", "GiST"),
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errdetail("Expected %08x, got %08x.",
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GIST_PAGE_ID,
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opaq->gist_page_id)));
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/* Avoid bogus PageGetMaxOffsetNumber() call with deleted pages */
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if (GistPageIsDeleted(page))
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elog(NOTICE, "page is deleted");
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else
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maxoff = PageGetMaxOffsetNumber(page);
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for (offset = FirstOffsetNumber;
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offset <= maxoff;
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offset++)
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{
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Datum values[5];
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bool nulls[5];
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ItemId id;
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IndexTuple itup;
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bytea *tuple_bytea;
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int tuple_len;
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id = PageGetItemId(page, offset);
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if (!ItemIdIsValid(id))
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elog(ERROR, "invalid ItemId");
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itup = (IndexTuple) PageGetItem(page, id);
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tuple_len = IndexTupleSize(itup);
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memset(nulls, 0, sizeof(nulls));
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values[0] = DatumGetInt16(offset);
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values[1] = ItemPointerGetDatum(&itup->t_tid);
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values[2] = Int32GetDatum((int) IndexTupleSize(itup));
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tuple_bytea = (bytea *) palloc(tuple_len + VARHDRSZ);
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SET_VARSIZE(tuple_bytea, tuple_len + VARHDRSZ);
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memcpy(VARDATA(tuple_bytea), itup, tuple_len);
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values[3] = BoolGetDatum(ItemIdIsDead(id));
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values[4] = PointerGetDatum(tuple_bytea);
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tuplestore_putvalues(tupstore, tupdesc, values, nulls);
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}
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return (Datum) 0;
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}
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Datum
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gist_page_items(PG_FUNCTION_ARGS)
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{
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bytea *raw_page = PG_GETARG_BYTEA_P(0);
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Oid indexRelid = PG_GETARG_OID(1);
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ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo;
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bool randomAccess;
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Relation indexRel;
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TupleDesc tupdesc;
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Tuplestorestate *tupstore;
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MemoryContext oldcontext;
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Page page;
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OffsetNumber offset;
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OffsetNumber maxoff = InvalidOffsetNumber;
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if (!superuser())
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ereport(ERROR,
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(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
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errmsg("must be superuser to use raw page functions")));
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/* check to see if caller supports us returning a tuplestore */
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if (rsinfo == NULL || !IsA(rsinfo, ReturnSetInfo))
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ereport(ERROR,
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(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
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errmsg("set-valued function called in context that cannot accept a set")));
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if (!(rsinfo->allowedModes & SFRM_Materialize))
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ereport(ERROR,
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(errcode(ERRCODE_SYNTAX_ERROR),
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errmsg("materialize mode required, but it is not allowed in this context")));
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/* The tupdesc and tuplestore must be created in ecxt_per_query_memory */
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oldcontext = MemoryContextSwitchTo(rsinfo->econtext->ecxt_per_query_memory);
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if (get_call_result_type(fcinfo, NULL, &tupdesc) != TYPEFUNC_COMPOSITE)
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elog(ERROR, "return type must be a row type");
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randomAccess = (rsinfo->allowedModes & SFRM_Materialize_Random) != 0;
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tupstore = tuplestore_begin_heap(randomAccess, false, work_mem);
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rsinfo->returnMode = SFRM_Materialize;
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rsinfo->setResult = tupstore;
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rsinfo->setDesc = tupdesc;
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MemoryContextSwitchTo(oldcontext);
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/* Open the relation */
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indexRel = index_open(indexRelid, AccessShareLock);
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if (!IS_GIST(indexRel))
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ereport(ERROR,
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(errcode(ERRCODE_WRONG_OBJECT_TYPE),
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errmsg("\"%s\" is not a %s index",
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RelationGetRelationName(indexRel), "GiST")));
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page = get_page_from_raw(raw_page);
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if (PageIsNew(page))
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{
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index_close(indexRel, AccessShareLock);
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PG_RETURN_NULL();
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}
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/* Avoid bogus PageGetMaxOffsetNumber() call with deleted pages */
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if (GistPageIsDeleted(page))
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elog(NOTICE, "page is deleted");
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else
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maxoff = PageGetMaxOffsetNumber(page);
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for (offset = FirstOffsetNumber;
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offset <= maxoff;
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offset++)
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{
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Datum values[5];
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bool nulls[5];
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ItemId id;
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IndexTuple itup;
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Datum itup_values[INDEX_MAX_KEYS];
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bool itup_isnull[INDEX_MAX_KEYS];
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char *key_desc;
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id = PageGetItemId(page, offset);
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if (!ItemIdIsValid(id))
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elog(ERROR, "invalid ItemId");
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itup = (IndexTuple) PageGetItem(page, id);
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index_deform_tuple(itup, RelationGetDescr(indexRel),
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itup_values, itup_isnull);
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memset(nulls, 0, sizeof(nulls));
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values[0] = DatumGetInt16(offset);
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values[1] = ItemPointerGetDatum(&itup->t_tid);
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values[2] = Int32GetDatum((int) IndexTupleSize(itup));
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values[3] = BoolGetDatum(ItemIdIsDead(id));
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key_desc = BuildIndexValueDescription(indexRel, itup_values, itup_isnull);
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if (key_desc)
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values[4] = CStringGetTextDatum(key_desc);
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else
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{
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values[4] = (Datum) 0;
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nulls[4] = true;
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}
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tuplestore_putvalues(tupstore, tupdesc, values, nulls);
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}
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relation_close(indexRel, AccessShareLock);
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return (Datum) 0;
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}
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