[Tarantool-patches] [PATCH v2 1/1] sql: do not change order of inserted values
Vladislav Shpilevoy
v.shpilevoy at tarantool.org
Tue Apr 7 00:42:39 MSK 2020
Hi! Thanks for the patch!
See 2 questions below.
> diff --git a/src/box/sql.c b/src/box/sql.c
> index 27089bd..7c1eba2 100644
> --- a/src/box/sql.c
> +++ b/src/box/sql.c
> @@ -324,10 +324,17 @@ struct space *
> sql_ephemeral_space_create(uint32_t field_count, struct sql_key_info *key_info)
> {
> struct key_def *def = NULL;
> + uint32_t part_count = field_count;
> if (key_info != NULL) {
> def = sql_key_info_to_key_def(key_info);
> if (def == NULL)
> return NULL;
> + /*
> + * In case is_pk_rowid is true we can use rowid
> + * as the only part of the key.
> + */
> + if (key_info->is_pk_rowid)
> + part_count = 1;
1. On one hand this can really speed up ephemeral space comparators,
because we have special templates for single indexed unsigned field
if it is in 1, 2, or 3 column.
On the other hand this won't help, because rowid is the last column
somewhy. And these fast comparators won't help.
Can we make rowid first column?
> }
>
> struct region *region = &fiber()->gc;
> @@ -364,17 +371,20 @@ sql_ephemeral_space_create(uint32_t field_count, struct sql_key_info *key_info)
> }
> }
>
> - for (uint32_t i = 0; i < field_count; ++i) {
> + for (uint32_t i = 0; i < part_count; ++i) {
> struct key_part_def *part = &parts[i];
> - part->fieldno = i;
> + uint32_t j = i;
> + if (key_info != NULL && key_info->is_pk_rowid)
> + j = field_count - 1;
2. Does it make sense to use part count > 1, if we have rowid?
It is unique anyway.
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