/* Like PageInit() in the backend */
static void
page_init(Page page)
{
PageHeader p = (PageHeader) page;
/* Make sure all fields of page are zero, as well as unused space */
MemSet(p, 0, BLCKSZ);
/* p->pd_flags = 0; done by above MemSet */
p->pd_lower = SizeOfPageHeaderData;
p->pd_upper = BLCKSZ;
p->pd_special = BLCKSZ; /* no special area on heap pages */
PageSetPageSizeAndVersion(page, BLCKSZ, TARGET_PAGE_VERSION);
/* p->pd_prune_xid = InvalidTransactionId; done by above MemSet */
}
/*
* PageInit
* Initializes the contents of a page.
*/
void
PageInit(Page page, Size pageSize, Size specialSize)
{
PageHeader p = (PageHeader) page;
specialSize = MAXALIGN(specialSize);
Assert(pageSize == BLCKSZ);
Assert(pageSize > specialSize + SizeOfPageHeaderData);
/* Make sure all fields of page are zero, as well as unused space */
MemSet(p, 0, pageSize);
/* p->pd_flags = 0; done by above MemSet */
p->pd_lower = SizeOfPageHeaderData;
p->pd_upper = pageSize - specialSize;
p->pd_special = pageSize - specialSize;
PageSetPageSizeAndVersion(page, pageSize, PG_PAGE_LAYOUT_VERSION);
}
static const char *
convert_gpdb4_heap_page(char *page)
{
VERSION4_PageHeaderData *oldhdr;
PageHeader newhdr;
OffsetNumber off;
OffsetNumber maxoff;
if (PageGetPageSize(page) != BLCKSZ)
return "invalid block size on page";
/* Can only convert from GPDB4 format */
if (PageGetPageLayoutVersion(page) != 4)
return "invalid page version";
oldhdr = (VERSION4_PageHeaderData *) page;
/* Other checks that PageHeaderIsValid() normally performs */
if (!((oldhdr->pd_flags & ~PD_VALID_FLAG_BITS) == 0 &&
oldhdr->pd_lower >= SizeOfPageHeaderData &&
oldhdr->pd_lower <= oldhdr->pd_upper &&
oldhdr->pd_upper <= oldhdr->pd_special &&
oldhdr->pd_special <= BLCKSZ &&
oldhdr->pd_special == MAXALIGN(oldhdr->pd_special)))
return "invalid header";
/*
* Ok, it's a valid heap page, from GPDB4. We know how to convert that!
*/
/* 1. pd_prune_xid was added to page header */
/* 2. Line pointer flags were changed */
/* 3. HEAP_COMPRESSED flag was removed */
/* 4. On-disk representation of numerics was changed */
/*
* Also, money datatype was widened from 32 to 64 bits. (pg_upgrade
* should've refused the upgrade)
*/
/*
* First, check if there is enough space on the page, after we expand the header.
*/
oldhdr = (VERSION4_PageHeaderData *) page;
newhdr = (PageHeader) page;
/*
* If there isn't enough space on this page for the new header field, relocate a tuple
*/
make_room(page);
/*
* There is space. Move the line pointers. We also convert the line pointer flags
* while we're at it. Begin from end to beginning, so that we don't overwrite items
* we haven't processed yet.
*/
maxoff = (oldhdr->pd_lower - VERSION4_SizeOfPageHeaderData) / sizeof(ItemIdData); /* PageGetMaxOffsetNumber */
for (off = maxoff; off >= 1; off--)
{
ItemIdData iid = oldhdr->pd_linp[off - 1]; /* PageGetItemId */
if (iid.lp_flags == VERSION4_LP_UNUSED)
iid.lp_flags = LP_UNUSED;
else if (iid.lp_flags == VERSION4_LP_USED)
iid.lp_flags = LP_NORMAL;
else
{
/* LP_DELETE and LP_USED were never used on heap pages. */
return "unexpected LP_DELETE or LP_DEAD line pointer on old-format heap page";
}
newhdr->pd_linp[off - 1] = iid;
}
newhdr->pd_lower = (char *) &newhdr->pd_linp[maxoff] - (char *) page;
/* Initialize the field that was added after version 4 format */
newhdr->pd_prune_xid = 0;
/*
* Ok, the page header and line pointers are in the new format now. Mangle
* the tuples themselves
*/
for (off = 1; off <= maxoff; off++)
{
ItemId iid = PageGetItemId(page, off); /* we can use PageGetItemId now */
HeapTupleHeader htup;
if (!ItemIdIsNormal(iid))
continue;
htup = (HeapTupleHeader) PageGetItem(page, iid);
convert_heaptuple(htup);
}
/*
* Finally, change the version number.
*/
PageSetPageSizeAndVersion(page, BLCKSZ, TARGET_PAGE_VERSION);
return NULL;
}
