[tarantool-patches] Re: [PATCH] sql: remove useless pragmas

[n.pettik]

> On 6 Feb 2019, at 15:18, Stanislav Zudin <szudin at tarantool.org> wrote:
> 
> The pragmas "query_only" and "read_uncommitted" didn't affect anything and were removed.

Nit: please, fit commit message into 72 symbols.

What about “busy_timeout”? As I see from code it is also useless.
It may require to delete some code more code.

Moreover, last two arguments of index_list are still unused:

   386	void
   387	sql_pragma_index_list(struct Parse *parse, const char *tbl_name)
   388	{
...
   398			sqlite3VdbeMultiLoad(v, 1, "isisi", i, idx->def->name,
   399					     idx->def->opts.is_unique);

Function expects 5 args (int-string-int-string-int), but only three are passed.
Let’s remove them as well.

Finally, consider comment from P. Gulutzan and my answer attached to ticket.
In a nutshell, at least two points (except for notes above) should be fixed:
a) Raise an error if index_list accepts name of unexisting index;
b) Make sql_default_engine accept only string, not id.

You may expand current patch into patch-set.

> Closes #3733
> ---
> Branch: https://github.com/tarantool/tarantool/tree/stanztt/gh-3733-obsolete-pragmas
> Issue: https://github.com/tarantool/tarantool/issues/3733
> 
> src/box/sql/pragma.h    | 10 ----------
> src/box/sql/sqliteInt.h |  3 ---
> 2 files changed, 13 deletions(-)
> 
> diff --git a/src/box/sql/pragma.h b/src/box/sql/pragma.h
> index e60801608..6b27f83c2 100644
> --- a/src/box/sql/pragma.h
> +++ b/src/box/sql/pragma.h
> @@ -153,16 +153,6 @@ static const PragmaName aPragmaName[] = {
> 	 /* iArg:      */ 0},
> #endif
> #if !defined(SQLITE_OMIT_FLAG_PRAGMAS)
> -	{ /* zName:     */ "query_only",
> -	 /* ePragTyp:  */ PragTyp_FLAG,
> -	 /* ePragFlg:  */ PragFlg_Result0 | PragFlg_NoColumns1,
> -	 /* ColNames:  */ 0, 0,
> -	 /* iArg:      */ SQLITE_QueryOnly},
> -	{ /* zName:     */ "read_uncommitted",
> -	 /* ePragTyp:  */ PragTyp_FLAG,
> -	 /* ePragFlg:  */ PragFlg_Result0 | PragFlg_NoColumns1,
> -	 /* ColNames:  */ 0, 0,

Personally I would add very simple tests to make sure
that these pragmas can’t be used anymore.