[PATCH v2 11/14] vinyl: do not fill secondary tuples with nulls when decoded
Vladimir Davydov
vdavydov.dev at gmail.com
Wed Mar 13 15:45:04 MSK 2019
On Wed, Mar 13, 2019 at 03:25:59PM +0300, Konstantin Osipov wrote:
> * Vladimir Davydov <vdavydov.dev at gmail.com> [19/03/13 11:58]:
> > +struct key_def *
> > +key_def_extract(const struct key_def *cmp_def, const struct key_def *pk_def,
> > + struct region *region)
>
> The name is not very telling :(
>
> It also looks like a standalone function, not a key_def method. So
> we could name it build_pk_def_for_cmp_def or
> find_primary_key_parts() or something like it.
Well, key_def_merge is also not a key_def method in this regard.
I think of key_def_ more like as of a namespace.
>
> > if (lsm == NULL) {
> > free(index);
> > return NULL;
> > @@ -1301,13 +1300,34 @@ vy_get_by_secondary_tuple(struct vy_lsm *lsm, struct vy_tx *tx,
> > const struct vy_read_view **rv,
> > struct tuple *tuple, struct tuple **result)
> > {
> > + int rc = 0;
> > assert(lsm->index_id > 0);
> >
> > - if (vy_point_lookup(lsm->pk, tx, rv, tuple, result) != 0)
> > - return -1;
> > + /*
> > + * Lookup the full tuple by a secondary statement.
> > + * There are two cases: the secondary statement may be
> > + * a key, in which case we need to extract the primary
> Please explain:
>
> may be a key, if we got this tuple from disk ... or may be a full
> tuple if we got this tuple from the tuple cache or level 0,
Okay.
>
> > + * key parts from it; or it may be a full tuple, which
> > + * we may pass it immediately to the iterator.
> > + */
> > + struct tuple *key;
> > + /*
> > + * To save disk space, we do not store full tuples
> > + * in secondary index runs. Instead we only store
> > + * extended keys (i.e. keys consisting of secondary
> > + * and primary index parts). This is enough to look
> > + * up a full tuple in the primary index.
> > + */
> > + lsm->disk_format = lsm_env->key_format;
>
> Nice.
>
> > +
> > + lsm->pk_in_cmp_def = key_def_extract(lsm->cmp_def, pk->key_def,
>
> Oh. Shall we call the function find_pk_in_cmp_def()?
The name's fine. Well, at least one can figure out what the function
does, but I don't quite like that there's no key_def_ prefix.
> > + if (is_primary)
> > + stmt = vy_stmt_new_surrogate_from_key(request.key,
>
> Shouldn't this be renamed?
The next patch removes this function altogether.
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