[RFC PATCH 08/23] vinyl: check key uniqueness before modifying tx write set

[Konstantin Osipov]

* Vladimir Davydov <vdavydov.dev at gmail.com> [18/07/08 22:52]:
> +	if (found != NULL && vy_tuple_compare(stmt, found,
> +					      lsm->pk->key_def) == 0) {
> +		/*
> +		 * If the old and new tuples are the same in
> +		 * terms of the primary key definition, the
> +		 * statement doesn't modify the secondary key
> +		 * and so there's actually no conflict.
> +		 */
> +		tuple_unref(found);
> +		return 0;
> +	}

In memtx, we pass old_tuple in txn_stmt around so that we can
check that found == old_tuple and ignore the duplicate (please
take a look at replace_check_dup). Why not do the same here, it
would save us a compare?

> +
> +	/*
> +	 * For secondary indexes, uniqueness must be checked on both
> +	 * INSERT and REPLACE.
> +	 */
> +	for (uint32_t i = 1; i < space->index_count; i++) {
> +		struct vy_lsm *lsm = vy_lsm(space->index[i]);
> +		if (vy_check_is_unique_secondary(env, tx, rv, space_name(space),
> +						 index_name_by_id(space, i),
> +						 lsm, stmt) != 0)
> +			return -1;
> +	}
> +	return 0;

This code calls vy_get(), which in turns makes an unnecessary
lookup in the primary key.


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Konstantin Osipov, Moscow, Russia, +7 903 626 22 32
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