Horton

Re: [COMMITTERS] pgsql: Fix freezing of a dead HOT-updated tuple

Robert Haas <robertmhaas@gmail.com>

View thread View on postgr.es
From: Robert Haas <robertmhaas@gmail.com>
To: Peter Geoghegan <pg@bowt.ie>
Cc: Alvaro Herrera <alvherre@alvh.no-ip.org>, PostgreSQL Hackers <pgsql-hackers@postgresql.org>, "Wood, Dan" <hexpert@amazon.com>
Date: 2017-09-28T22:20:51Z
Lists: pgsql-hackers 
On Thu, Sep 28, 2017 at 5:47 PM, Peter Geoghegan <pg@bowt.ie> wrote:
> In the end, commit 6bfa88a fixed that old recovery bug by making sure
> the recovery routine heap_xlog_lock() did the right thing. In both
> cases (Feb 2014 and today), the index wasn't really corrupt -- it just
> pointed to the root of a HOT chain when it should point to some child
> tuple (or maybe a successor HOT chain).

Unless I'm very confused, it's really not OK to point at a child tuple
rather than the root of the HOT chain.

Pointing to a successor HOT chain would be OK, as long as you point to
the root tuple thereof.

-- 
Robert Haas
EnterpriseDB: http://www.enterprisedb.com
The Enterprise PostgreSQL Company

Commits

  1. Backport addition of rs_old_rel to rewriteheap's state.

  2. Perform a lot more sanity checks when freezing tuples.

  3. Revert bogus fixes of HOT-freezing bug

  4. Fix traversal of half-frozen update chains

  5. Fix freezing of a dead HOT-updated tuple

  6. During index build, check and elog (not just Assert) for broken HOT chain.

  7. Fix WAL replay of locking an updated tuple

  8. Change the way we mark tuples as frozen.