| From: | Teodor Sigaev <teodor(at)sigaev(dot)ru> |
|---|---|
| To: | Peter Geoghegan <pg(at)bowt(dot)ie> |
| Cc: | Michael Paquier <michael(at)paquier(dot)xyz>, Postgres hackers <pgsql-hackers(at)postgresql(dot)org>, Anastasia Lubennikova <a(dot)lubennikova(at)postgrespro(dot)ru> |
| Subject: | Re: Corrupted btree index on HEAD because of covering indexes |
| Date: | 2018-04-19 16:42:59 |
| Message-ID: | 97545a73-3a3b-713d-31e2-8e652faa9152@sigaev.ru |
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| Lists: | pgsql-hackers |
> I'll take a look tomorrow.
Interesting, contrib/amcheck doesn't find any error in index. Seems, it's
subject for further improvement.
Nevertheless, seems, I found. In _bt_mark_page_halfdead() we use truncated high
key IndexTuple as a storage of blocknumber of top parent to remove. And sets
BTreeTupleSetNAtts(&trunctuple, 0) - it's stored in ip_posid.
But some later, in _bt_unlink_halfdead_page() we check ItemPointer high key with
ItemPointerIsValid macro - and it returns false, because offset is actually
InvalidOffsetNumber - i.e. 0 which was set by BTreeTupleSetNAtts. And some wrong
decisions are follows, I didn't look at that.
Trivial and naive fix is attached, but for me it looks a bit annoing that we
store pointer (leafhikey) somewhere inside unlocked page.
--
Teodor Sigaev E-mail: teodor(at)sigaev(dot)ru
WWW: http://www.sigaev.ru/
| Attachment | Content-Type | Size |
|---|---|---|
| vacuum_nbtree.patch | text/x-patch | 618 bytes |
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