/*
* Perform the actual page changes needed by heap_page_prune.
* It is expected that the caller has suitable pin and lock on the
* buffer, and is inside a critical section.
*
* This is split out because it is also used by heap_xlog_clean()
* to replay the WAL record when needed after a crash. Note that the
* arguments are identical to those of log_heap_clean().
*/
void
heap_page_prune_execute(Buffer buffer,
OffsetNumber *redirected, int nredirected,
OffsetNumber *nowdead, int ndead,
OffsetNumber *nowunused, int nunused)
{
Page page = (Page) BufferGetPage(buffer);
OffsetNumber *offnum;
int i;
/* Update all redirected line pointers */
offnum = redirected;
for (i = 0; i < nredirected; i++)
{
OffsetNumber fromoff = *offnum++;
OffsetNumber tooff = *offnum++;
ItemId fromlp = PageGetItemId(page, fromoff);
ItemIdSetRedirect(fromlp, tooff);
}
/* Update all now-dead line pointers */
offnum = nowdead;
for (i = 0; i < ndead; i++)
{
OffsetNumber off = *offnum++;
ItemId lp = PageGetItemId(page, off);
ItemIdSetDead(lp);
}
/* Update all now-unused line pointers */
offnum = nowunused;
for (i = 0; i < nunused; i++)
{
OffsetNumber off = *offnum++;
ItemId lp = PageGetItemId(page, off);
ItemIdSetUnused(lp);
}
/*
* Finally, repair any fragmentation, and update the page's hint bit about
* whether it has free pointers.
*/
PageRepairFragmentation(page);
}
/*
* Perform the actual page changes needed by heap_page_prune.
* It is expected that the caller has suitable pin and lock on the
* buffer, and is inside a critical section.
*
* This is split out because it is also used by heap_xlog_clean()
* to replay the WAL record when needed after a crash. Note that the
* arguments are identical to those of log_heap_clean().
*/
void
heap_page_prune_execute(Buffer buffer,
OffsetNumber *redirected, int nredirected,
OffsetNumber *nowdead, int ndead,
OffsetNumber *nowunused, int nunused,
bool redirect_move)
{
Page page = (Page) BufferGetPage(buffer);
OffsetNumber *offnum;
int i;
/* Update all redirected or moved line pointers */
offnum = redirected;
for (i = 0; i < nredirected; i++)
{
OffsetNumber fromoff = *offnum++;
OffsetNumber tooff = *offnum++;
ItemId fromlp = PageGetItemId(page, fromoff);
if (redirect_move)
{
/* Physically move the "to" item to the "from" slot */
ItemId tolp = PageGetItemId(page, tooff);
HeapTupleHeader htup;
*fromlp = *tolp;
ItemIdSetUnused(tolp);
/*
* Change heap-only status of the tuple because after the line
* pointer manipulation, it's no longer a heap-only tuple, but is
* directly pointed to by index entries.
*/
Assert(ItemIdIsNormal(fromlp));
htup = (HeapTupleHeader) PageGetItem(page, fromlp);
Assert(HeapTupleHeaderIsHeapOnly(htup));
HeapTupleHeaderClearHeapOnly(htup);
}
else
{
/* Just insert a REDIRECT link at fromoff */
ItemIdSetRedirect(fromlp, tooff);
}
}
/* Update all now-dead line pointers */
offnum = nowdead;
for (i = 0; i < ndead; i++)
{
OffsetNumber off = *offnum++;
ItemId lp = PageGetItemId(page, off);
ItemIdSetDead(lp);
}
/* Update all now-unused line pointers */
offnum = nowunused;
for (i = 0; i < nunused; i++)
{
OffsetNumber off = *offnum++;
ItemId lp = PageGetItemId(page, off);
ItemIdSetUnused(lp);
}
/*
* Finally, repair any fragmentation, and update the page's hint bit about
* whether it has free pointers.
*/
PageRepairFragmentation(page);
}