Re: [Tarantool-patches] [PATCH] vinyl: account statement statistics during .index rebuild

[Nikita Pettik <korablev@tarantool.org>]

On 26 Nov 21:45, Vladislav Shpilevoy wrote:
> Hi! Thanks for the patch!
> 
> On 24.11.2020 22:03, Nikita Pettik wrote:
> > It may turn out to be necessary to re-create .index file corresponding
> > to .run file. During rebuild it was forgotten to account statement
> > statistics, i.e. count of INSERTs, DELETEs etc. Let's fix it and patch
> > vy_run_rebuild_index().
> > ---
> > Branch:
> > https://github.com/tarantool/tarantool/tree/np/vy-account-stmt-stat-on-index-rebuild
> > N.B. problem is obvious and trivial to fix. However, test for it is likely
> > to be way more sophisticated, so I haven't included it (but checked manually
> > that everything works fine).
> 
> How can I validate it manually?

Drop .index, run tarantool with force-recovery, cat the content of .index
file with tarantoolctl/xlog module.
 
> >  src/box/vy_run.c | 2 ++
> >  1 file changed, 2 insertions(+)
> > 
> > diff --git a/src/box/vy_run.c b/src/box/vy_run.c
> > index b9822dc3e..820a6ce3f 100644
> > --- a/src/box/vy_run.c
> > +++ b/src/box/vy_run.c
> > @@ -2452,6 +2452,8 @@ vy_run_rebuild_index(struct vy_run *run, const char *dir,
> >  					goto close_err;
> >  				}
> >  			}
> > +			vy_stmt_stat_acct(&run->info.stmt_stat,
> > +					  vy_stmt_type(tuple));
> 
> Why is it needed? The run is not created from the scratch. Only
> its index is rebuilt, which is not related to the statistics,
> AFAIU. The statements in the run are not changed here. It means
> it was filled some time ago, and everything should have already
> been accounted via vy_run_writer_write_to_page().

Possibly it doesn't affect anything, but just noted that in case
of re-creating .index files during force-recovery, they contained
zeroed statistics (in contrast to ordinary .index files). It may
turn out to be helpful e.g. during digging into vinyl problems.