Re: BUG #14529: Missing non pk data for "before image" in logical decoding

Hi,

On 06/02/17 17:12, philippe(dot)beaudoin(at)dalibo(dot)com wrote:
> The following bug has been logged on the website:
>
> Bug reference: 14529
> Logged by: Philippe BEAUDOIN
> Email address: philippe(dot)beaudoin(at)dalibo(dot)com
> PostgreSQL version: 9.6.1
> Operating system: Linux
> Description:
>
> I am currently studying the logical decoding mechanism as an alternative to
> log triggers for the E-Maj extension.
> Using pg_recvlogical and pgbench, I have been able to reproduce an issue
> that I met.
>
> [...snip...]
>
> BEGIN 5454770
> table public.pgbench_accounts: UPDATE: old-key: aid[integer]:24469
> bid[integer]:1 abalance[integer]:0 filler[character]:'
> ' new-tuple:
> aid[integer]:24469 bid[integer]:1 abalance[integer]:-3373
> filler[character]:'
> '
> table public.pgbench_tellers: UPDATE: old-key: tid[integer]:2 bid[integer]:1
> tbalance[integer]:0 new-tuple: tid[integer]:2 bid[integer]:1
> tbalance[integer]:-3373 filler[character]:null
> table public.pgbench_branches: UPDATE: old-key: bid[integer]:1
> bbalance[integer]:0 new-tuple: bid[integer]:1 bbalance[integer]:-3373
> filler[character]:null
> table public.pgbench_history: INSERT: tid[integer]:2 bid[integer]:1
> aid[integer]:24469 delta[integer]:-3373 mtime[timestamp without time
> zone]:'2017-01-21 09:51:29.728733' filler[character]:null
> COMMIT 5454770
> BEGIN 5454771
> table public.pgbench_accounts: UPDATE: old-key: aid[integer]:4016
> bid[integer]:1 abalance[integer]:0 filler[character]:'
> ' new-tuple:
> aid[integer]:4016 bid[integer]:1 abalance[integer]:3308 filler[character]:'
>
> '
> table public.pgbench_tellers: UPDATE: old-key: tid[integer]:2 bid[integer]:1
> tbalance[integer]:-3373 new-tuple: tid[integer]:2 bid[integer]:1
> tbalance[integer]:-65 filler[character]:null
> table public.pgbench_branches: UPDATE: old-key: bid[integer]:1
> bbalance[integer]:-3373 new-tuple: bid[integer]:1 bbalance[integer]:-65
> filler[character]:null
> table public.pgbench_history: INSERT: tid[integer]:2 bid[integer]:1
> aid[integer]:4016 delta[integer]:3308 mtime[timestamp without time
> zone]:'2017-01-21 09:51:29.74555' filler[character]:null
> COMMIT 5454771
> #-------------------------------------------------------------------------------
>
> The incomplete UPDATEs concern pgbench_tellers and pgbench_branches
> tables.
>

Seems to me like what you see here is not bug but just behavior of
test_decoding plugin which skips NULL values from old-key printing - see
the tuple_to_stringinfo() function and calls to it from pg_decode_change().

--
Petr Jelinek http://www.2ndQuadrant.com/
PostgreSQL Development, 24x7 Support, Training & Services