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 Fri,  3 Apr 2020 18:19:37 +0300 (MSK)
Date: Fri, 3 Apr 2020 15:19:36 +0000
From: Nikita Pettik <korablev@tarantool.org>
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References: <cover.1585559306.git.k.sosnin@tarantool.org>
 <68bbb40b963e1c4ef4a1950a01e67453fc252347.1585559306.git.k.sosnin@tarantool.org>
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In-Reply-To: <68bbb40b963e1c4ef4a1950a01e67453fc252347.1585559306.git.k.sosnin@tarantool.org>
Subject: Re: [Tarantool-patches] [PATCH 4/4] sql: provide a user friendly
 frontend for accessing session settings
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To: Chris Sosnin <k.sosnin@tarantool.org>
Cc: tarantool-patches@dev.tarantool.org, v.shpilevoy@tarantool.org

On 30 Mar 12:13, Chris Sosnin wrote:
> diff --git a/src/box/sql/build.c b/src/box/sql/build.c
> index a00da31f9..cdcf8b6d8 100644
> --- a/src/box/sql/build.c
> +++ b/src/box/sql/build.c
> @@ -3481,3 +3481,28 @@ sql_session_settings_init()
>  		setting->set = sql_session_setting_set;
>  	}
>  }
> +
> +void
> +sql_setting_set(struct Parse *parse_context, struct Token *name,
> +		struct Expr *expr)
> +{
> +	struct Vdbe *vdbe = sqlGetVdbe(parse_context);
> +	if (vdbe == NULL)
> +		goto abort;
> +	sqlVdbeCountChanges(vdbe);
> +	char *key = sql_name_from_token(parse_context->db, name);
> +	if (key == NULL)
> +		goto abort;
> +	int index = session_setting_find(key);
> +	if (index >= 0) {
> +		int target = ++parse_context->nMem;
> +		sqlExprCode(parse_context, expr, target);
> +		sqlVdbeAddOp2(vdbe, OP_SetSetting, index, target);
> +		return;
> +	}
> +	diag_set(ClientError, ER_SQL_PARSER_GENERIC,
> +		 tt_sprintf("Session setting %s doesn't exist", key));

Mb it is worth moving this check to runtime? I.e. pass to OP_SetSetting
name of setting to be set. The less appeals to system spaces and
cache look ups are made, the better parsing process is organized.

The rest is ok.