regress_injection.c File Reference

#include "postgres.h"
#include "access/table.h"
#include "fmgr.h"
#include "miscadmin.h"
#include "postmaster/autovacuum.h"
#include "storage/procarray.h"
#include "utils/rel.h"
#include "utils/xid8.h"

Include dependency graph for regress_injection.c:

Go to the source code of this file.

Functions
	PG_FUNCTION_INFO_V1 (removable_cutoff)
Datum	removable_cutoff (PG_FUNCTION_ARGS)

Function Documentation

PG_FUNCTION_INFO_V1()

PG_FUNCTION_INFO_V1

(

removable_cutoff

)

removable_cutoff()

Datum removable_cutoff

(

PG_FUNCTION_ARGS

)

Definition at line 42 of file regress_injection.c.

{
    Relation    rel = NULL;
    TransactionId xid;
    FullTransactionId next_fxid_before,
                next_fxid;
 
    /* could take other relkinds callee takes, but we've not yet needed it */
    if (!PG_ARGISNULL(0))
        rel = table_open(PG_GETARG_OID(0), AccessShareLock);
 
    if (!rel->rd_rel->relisshared && autovacuum_start_daemon)
        elog(WARNING,
             "removable_cutoff(non-shared-rel) can move backward under autovacuum=on");
 
    /*
     * No lock or snapshot necessarily prevents oldestXid from advancing past
     * "xid" while this function runs.  That concerns us only in that we must
     * not ascribe "xid" to the wrong epoch.  (That may never arise in
     * isolation testing, but let's set a good example.)  As a crude solution,
     * retry until nextXid doesn't change.
     */
    next_fxid = ReadNextFullTransactionId();
    do
    {
        CHECK_FOR_INTERRUPTS();
        next_fxid_before = next_fxid;
        xid = GetOldestNonRemovableTransactionId(rel);
        next_fxid = ReadNextFullTransactionId();
    } while (!FullTransactionIdEquals(next_fxid, next_fxid_before));
 
    if (rel)
        table_close(rel, AccessShareLock);
 
    PG_RETURN_FULLTRANSACTIONID(FullTransactionIdFromAllowableAt(next_fxid,
                                                                 xid));
}

References AccessShareLock, autovacuum_start_daemon, CHECK_FOR_INTERRUPTS, elog, FullTransactionIdEquals, FullTransactionIdFromAllowableAt(), GetOldestNonRemovableTransactionId(), PG_ARGISNULL, PG_GETARG_OID, PG_RETURN_FULLTRANSACTIONID, RelationData::rd_rel, ReadNextFullTransactionId(), table_close(), table_open(), and WARNING.