Re: [HACKERS] WIP Patch: Precalculate stable functions,infrastructure v1

> On 31 December 2017 at 06:55, Marina Polyakova <m.polyakova@postgrespro.ru> wrote:

>

> Secondly, here there's a sixth version of the patch for the precalculation of

> stable or immutable functions, stable or immutable operators and other

> nonvolatile expressions.

Thanks for your patch, looks quite interesting!

> To not send big patch I have split it (that's why version starts with the

> first again) and here I send infrastructure patch which includes:

Yeah, but it's still 18k lines :) After the first quick glance I have a few

small questions.

If I call a stable function from a query and subquery, looks like it's cached:

```

=# select stable_with_int(1) from (select stable_with_int(1) from x) q;

NOTICE:  00000: stable with int

LOCATION:  exec_stmt_raise, pl_exec.c:3353

 stable_with_int

-----------------

               1

               1

               1

               1

(4 rows)

```

But the same from CTE works different, is it supposed to be like that?

```

=# with data as (select stable_with_int(1) from x) select stable_with_int(1) from data;

NOTICE:  00000: stable with int

LOCATION:  exec_stmt_raise, pl_exec.c:3353

NOTICE:  00000: stable with int

LOCATION:  exec_stmt_raise, pl_exec.c:3353

 stable_with_int

-----------------

               1

               1

               1

               1

(4 rows)

```

Also I see this pattern quite some time, maybe it makes sense to move it to a function?

```

+ /* create and return CachedExpr */

+ CachedExpr *new_node = makeNode(CachedExpr);

+ new_node->subexpr = (CacheableExpr *) current_node;

+

+ context->root->hasCachedExpr = true;

+

+ return (Node *) new_node;

```