"V. M." <[EMAIL PROTECTED]> writes: > sometimes i'm getting: > NOTICE: Child itemid in update-chain marked as unused - can't > continue repair_frag > during a simple "vacuum", db is online. > pg version 7.1, on debian linux kernel 2.4. > what's the problem? The source code says: /* * This means that in the middle of chain there * was tuple updated by older (than XmaxRecent) * xaction and this tuple is already deleted by * me. Actually, upper part of chain should be * removed and seems that this should be handled * in scan_heap(), but it's not implemented at the * moment and so we just stop shrinking here. */ In short, an unimplemented special case in VACUUM's logic that tries to compact out free space by moving tuples around. Most people never see this message though. There must be something unusual about the pattern of updates being done on this particular table, that you see it often. regards, tom lane ---------------------------(end of broadcast)--------------------------- TIP 3: if posting/reading through Usenet, please send an appropriate subscribe-nomail command to [EMAIL PROTECTED] so that your message can get through to the mailing list cleanly