Fix failure when a shared tidbitmap has only one page.

Commit 98e6e89040a0534ca26914c66cae9dd49ef62ad9 made inadequate
provision for the case of a single-page shared tidbitmap.  It
allocate space for a shared PagetableEntry, but failed to
initialize it.

Report by Thomas Munro.  Patch by Dilip Kumar, with some comment
changes by me.

Discussion: http://postgr.es/m/CAEepm=19Cmnfbi-j2Bw-a6yGPeHE1OVhKvvKz9bRBTJGKfGHMA@mail.gmail.com
This commit is contained in:
Robert Haas 2017-04-11 12:03:12 -04:00
parent 28b0478755
commit 4c3b59abf4

View File

@ -866,12 +866,14 @@ tbm_prepare_shared_iterate(TIDBitmap *tbm)
else if (tbm->status == TBM_ONE_PAGE)
{
/*
* In one page mode allocate the space for one pagetable entry and
* directly store its index i.e. 0 in page array
* In one page mode allocate the space for one pagetable entry,
* initialize it, and directly store its index (i.e. 0) in the
* page array.
*/
tbm->dsapagetable = dsa_allocate(tbm->dsa, sizeof(PTEntryArray) +
sizeof(PagetableEntry));
ptbase = dsa_get_address(tbm->dsa, tbm->dsapagetable);
memcpy(ptbase->ptentry, &tbm->entry1, sizeof(PagetableEntry));
ptpages->index[0] = 0;
}