diff options
Diffstat (limited to 'src/backend/access/gist/gistutil.c')
| -rw-r--r-- | src/backend/access/gist/gistutil.c | 24 |
1 files changed, 21 insertions, 3 deletions
diff --git a/src/backend/access/gist/gistutil.c b/src/backend/access/gist/gistutil.c index 7d1b219bbc8..97260201dcd 100644 --- a/src/backend/access/gist/gistutil.c +++ b/src/backend/access/gist/gistutil.c @@ -882,9 +882,27 @@ gistNewBuffer(Relation r) bool gistPageRecyclable(Page page) { - return PageIsNew(page) || - (GistPageIsDeleted(page) && - TransactionIdPrecedes(GistPageGetDeleteXid(page), RecentGlobalXmin)); + if (PageIsNew(page)) + return true; + if (GistPageIsDeleted(page)) + { + /* + * The page was deleted, but when? If it was just deleted, a scan + * might have seen the downlink to it, and will read the page later. + * As long as that can happen, we must keep the deleted page around as + * a tombstone. + * + * Compare the deletion XID with RecentGlobalXmin. If deleteXid < + * RecentGlobalXmin, then no scan that's still in progress could have + * seen its downlink, and we can recycle it. + */ + FullTransactionId deletexid_full = GistPageGetDeleteXid(page); + FullTransactionId recentxmin_full = GetFullRecentGlobalXmin(); + + if (FullTransactionIdPrecedes(deletexid_full, recentxmin_full)) + return true; + } + return false; } bytea * |