[tarantool-patches] Re: [PATCH v2 7/8] sql: get rid of FuncDef function hash
n.pettik
korablev at tarantool.org
Tue Aug 20 19:06:03 MSK 2019
>>> + /** A call method for a function. */
>>
>> Add explanation why we don’t use basic (i.e. call
>> method of base class) “call” method. Furthermore,
>> built-ins are called bypassing func_access_check()
>> function. This should be either documented or fixed.
> /**
> * A VDBE-memory-compatible call method for a function.
> * SQL Builting functions doesn't use base class call
Builting -> built-in; doesn’t -> don't
> * method to gain the best possible performance for SQL
> * requests.
Can’t parse this sentence at all.
> As builtin functions are predefined and
> * non of them modifie schema, access checks are
God please, use spell checker.
> * redundant, functions have the same execution
> * privileges as SQL.
> */
> void (*call)(sql_context *ctx, int argc, sql_value **argv);
>
>>> +/**
>>> + * Memory cell pMem contains the context of an aggregate function.
>>
>> Nit: pMem -> mem.
> Fixed.
It’s not.
>>> assert(func != NULL);
>>
>> Instead of asserting func existence let’s raise an error: now
>> user can remove built-in function from hash - there’s no
>> protection to avoid such cases. Note that such opportunity
>> (removing built-ins from cache) has been introduced by moving
>> built-ins to the global func cache. In this case, assertion will fail
>> in debug mode and lead to unpredictable consequences in
>> release mode. Another option is to introduce mentioned protection,
>> i.e. disallow user to delete functions which are declared with
>> FUNC_LANGUAGE_SQL_BUILTIN flag.
> I've introduce remove protection in alter.cc
Well, now we have another problem: user can create
built-in function, but can’t drop it:
tarantool> box.schema.func.create('WAITFOR', {language = 'SQL_BUILTIN', param_list = {'integer'}, returns = 'integer',exports = {'SQL'}})
---
…
tarantool> box.schema.func.drop('WAITFOR')
---
- error: 'Can''t drop function 1: function is SQL builtin'
...
>> Can aggregate function be non-builtin?
> Not for now, but I don't like to rely on it so I make all
> corresponding checks.
Please, don’t cut the context related to comment.
Add assertion than, instead of absolutely redundant if-check.
If someday ability of declaring non-builtins as aggregates
would be introduced, one can easily find and fix this place.
>> user_data is used only for min/max functions. Let’s consider removing it.
> Removed user_data at all.
I’d better move it in a separate commit.
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