Re: Bugs in TOAST handling, OID assignment and redo recovery

On Wed, Apr 18, 2018 at 12:07:52PM +0530, Pavan Deolasee wrote:
>
>
> On Thu, Apr 12, 2018 at 5:53 AM, Peter Eisentraut <
> peter(dot)eisentraut(at)2ndquadrant(dot)com> wrote:
>
> On 4/10/18 06:29, Pavan Deolasee wrote:
> > One of our 2ndQuadrant support customers recently reported a sudden rush
> > of TOAST errors post a crash recovery, nearly causing an outage. Most
> > errors read like this:
> >
> > ERROR: unexpected chunk number 0 (expected 1) for toast value nnnn
>
> While researching this, I found that the terminology in this code is
> quite inconsistent.  It talks about chunks ids, chunk indexes, chunk
> numbers, etc. seemingly interchangeably.  The above error is actually
> about the chunk_seq, not about the chunk_id, as one might think.
>
> The attached patch is my attempt to clean this up a bit.  Thoughts?
>
>
> While I agree that we should clean it up, I wonder if changing error text would
> be a good idea. These errors are being reported by a very long time and if we
> change the text, we might forget the knowledge about the past reports.
>
> Also, "toast value" is same as "chunk_id". Should we clean up something there
> too? "chunk_seq number" -- should that be just "chunk_seq"?

We can put a comment next to the error message C string if we want to
keep historical knowledge.

--
Bruce Momjian <bruce(at)momjian(dot)us> http://momjian.us
EnterpriseDB http://enterprisedb.com

+ As you are, so once was I. As I am, so you will be. +
+ Ancient Roman grave inscription +