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https://git.postgresql.org/git/postgresql.git
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7971539020
no longer returns buffer pointer, can be gotten from scan; descriptor; bootstrap can create multi-key indexes; pg_procname index now is multi-key index; oidint2, oidint4, oidname are gone (must be removed from regression tests); use System Cache rather than sequential scan in many places; heap_modifytuple no longer takes buffer parameter; remove unused buffer parameter in a few other functions; oid8 is not index-able; remove some use of single-character variable names; cleanup Buffer variables usage and scan descriptor looping; cleaned up allocation and freeing of tuples; 18k lines of diff;
254 lines
7.2 KiB
C
254 lines
7.2 KiB
C
/*-------------------------------------------------------------------------
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*
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* tqual.c--
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* POSTGRES "time" qualification code.
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*
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* Copyright (c) 1994, Regents of the University of California
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*
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*
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* IDENTIFICATION
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* $Header: /cvsroot/pgsql/src/backend/utils/time/tqual.c,v 1.17 1998/08/19 02:03:28 momjian Exp $
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*
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*-------------------------------------------------------------------------
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*/
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/* #define TQUALDEBUG 1 */
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#include "postgres.h"
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#include "access/htup.h"
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#include "access/xact.h"
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#include "storage/bufmgr.h"
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#include "access/transam.h"
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#include "utils/elog.h"
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#include "utils/palloc.h"
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#include "utils/tqual.h"
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extern bool PostgresIsInitialized;
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/*
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* XXX Transaction system override hacks start here
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*/
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#ifndef GOODAMI
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TransactionId HeapSpecialTransactionId = InvalidTransactionId;
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CommandId HeapSpecialCommandId = FirstCommandId;
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void
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setheapoverride(bool on)
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{
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if (on)
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{
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TransactionIdStore(GetCurrentTransactionId(),
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&HeapSpecialTransactionId);
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HeapSpecialCommandId = GetCurrentCommandId();
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}
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else
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HeapSpecialTransactionId = InvalidTransactionId;
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}
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#endif /* !defined(GOODAMI) */
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/*
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* XXX Transaction system override hacks end here
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*/
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/*
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* HeapTupleSatisfiesItself --
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* True iff heap tuple is valid for "itself."
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* "{it}self" means valid as of everything that's happened
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* in the current transaction, _including_ the current command.
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*
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* Note:
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* Assumes heap tuple is valid.
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*/
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/*
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* The satisfaction of "itself" requires the following:
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*
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* ((Xmin == my-transaction && the row was updated by the current transaction, and
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* (Xmax is null it was not deleted
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* [|| Xmax != my-transaction)]) [or it was deleted by another transaction]
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* ||
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*
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* (Xmin is committed && the row was modified by a committed transaction, and
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* (Xmax is null || the row has not been deleted, or
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* (Xmax != my-transaction && the row was deleted by another transaction
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* Xmax is not committed))) that has not been committed
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*/
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bool
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HeapTupleSatisfiesItself(HeapTuple tuple)
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{
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if (!(tuple->t_infomask & HEAP_XMIN_COMMITTED))
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{
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if (tuple->t_infomask & HEAP_XMIN_INVALID) /* xid invalid or
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* aborted */
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return (false);
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if (TransactionIdIsCurrentTransactionId(tuple->t_xmin))
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{
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if (tuple->t_infomask & HEAP_XMAX_INVALID) /* xid invalid */
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return (true);
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else
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return (false);
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}
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if (!TransactionIdDidCommit(tuple->t_xmin))
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{
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if (TransactionIdDidAbort(tuple->t_xmin))
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tuple->t_infomask |= HEAP_XMIN_INVALID; /* aborted */
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return (false);
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}
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tuple->t_infomask |= HEAP_XMIN_COMMITTED;
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}
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/* the tuple was inserted validly */
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if (tuple->t_infomask & HEAP_XMAX_INVALID) /* xid invalid or aborted */
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return (true);
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if (tuple->t_infomask & HEAP_XMAX_COMMITTED)
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return (false);
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if (TransactionIdIsCurrentTransactionId(tuple->t_xmax))
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return (false);
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if (!TransactionIdDidCommit(tuple->t_xmax))
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{
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if (TransactionIdDidAbort(tuple->t_xmax))
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tuple->t_infomask |= HEAP_XMAX_INVALID; /* aborted */
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return (true);
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}
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/* by here, deleting transaction has committed */
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tuple->t_infomask |= HEAP_XMAX_COMMITTED;
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return (false);
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}
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/*
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* HeapTupleSatisfiesNow --
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* True iff heap tuple is valid "now."
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* "now" means valid including everything that's happened
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* in the current transaction _up to, but not including,_
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* the current command.
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*
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* Note:
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* Assumes heap tuple is valid.
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*/
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/*
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* The satisfaction of "now" requires the following:
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*
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* ((Xmin == my-transaction && changed by the current transaction
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* Cmin != my-command && but not by this command, and
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* (Xmax is null || the row has not been deleted, or
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* (Xmax == my-transaction && it was deleted by the current transaction
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* Cmax != my-command))) but not by this command,
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* || or
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*
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* (Xmin is committed && the row was modified by a committed transaction, and
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* (Xmax is null || the row has not been deleted, or
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* (Xmax == my-transaction && the row is being deleted by this command, or
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* Cmax == my-command) ||
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* (Xmax is not committed && the row was deleted by another transaction
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* Xmax != my-transaction)))) that has not been committed
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*
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* XXX
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* CommandId stuff didn't work properly if one used SQL-functions in
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* UPDATE/INSERT(fromSELECT)/DELETE scans: SQL-funcs call
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* CommandCounterIncrement and made tuples changed/inserted by
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* current command visible to command itself (so we had multiple
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* update of updated tuples, etc). - vadim 08/29/97
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*
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* mao says 17 march 1993: the tests in this routine are correct;
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* if you think they're not, you're wrong, and you should think
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* about it again. i know, it happened to me. we don't need to
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* check commit time against the start time of this transaction
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* because 2ph locking protects us from doing the wrong thing.
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* if you mess around here, you'll break serializability. the only
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* problem with this code is that it does the wrong thing for system
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* catalog updates, because the catalogs aren't subject to 2ph, so
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* the serializability guarantees we provide don't extend to xacts
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* that do catalog accesses. this is unfortunate, but not critical.
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*/
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bool
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HeapTupleSatisfiesNow(HeapTuple tuple)
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{
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if (AMI_OVERRIDE)
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return true;
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/*
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* If the transaction system isn't yet initialized, then we assume
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* that transactions committed. We only look at system catalogs
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* during startup, so this is less awful than it seems, but it's still
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* pretty awful.
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*/
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if (!PostgresIsInitialized)
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return ((bool) (TransactionIdIsValid(tuple->t_xmin) &&
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!TransactionIdIsValid(tuple->t_xmax)));
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if (!(tuple->t_infomask & HEAP_XMIN_COMMITTED))
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{
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if (tuple->t_infomask & HEAP_XMIN_INVALID) /* xid invalid or
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* aborted */
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return (false);
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if (TransactionIdIsCurrentTransactionId(tuple->t_xmin))
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{
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if (CommandIdGEScanCommandId(tuple->t_cmin))
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return (false); /* inserted after scan started */
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if (tuple->t_infomask & HEAP_XMAX_INVALID) /* xid invalid */
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return (true);
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Assert(TransactionIdIsCurrentTransactionId(tuple->t_xmax));
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if (CommandIdGEScanCommandId(tuple->t_cmax))
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return (true); /* deleted after scan started */
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else
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return (false); /* deleted before scan started */
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}
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/*
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* this call is VERY expensive - requires a log table lookup.
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*/
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if (!TransactionIdDidCommit(tuple->t_xmin))
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{
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if (TransactionIdDidAbort(tuple->t_xmin))
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tuple->t_infomask |= HEAP_XMIN_INVALID; /* aborted */
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return (false);
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}
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tuple->t_infomask |= HEAP_XMIN_COMMITTED;
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}
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/* by here, the inserting transaction has committed */
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if (tuple->t_infomask & HEAP_XMAX_INVALID) /* xid invalid or aborted */
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return (true);
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if (tuple->t_infomask & HEAP_XMAX_COMMITTED)
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return (false);
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if (TransactionIdIsCurrentTransactionId(tuple->t_xmax))
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{
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if (CommandIdGEScanCommandId(tuple->t_cmax))
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return (true); /* deleted after scan started */
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else
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return (false); /* deleted before scan started */
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}
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if (!TransactionIdDidCommit(tuple->t_xmax))
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{
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if (TransactionIdDidAbort(tuple->t_xmax))
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tuple->t_infomask |= HEAP_XMAX_INVALID; /* aborted */
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return (true);
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}
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/* xmax transaction committed */
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tuple->t_infomask |= HEAP_XMAX_COMMITTED;
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return (false);
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}
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