[Tarantool-patches] [PATCH v2 2/5] box: introdice _vsession_settings sysview

[imeevma@tarantool.org]

Thank you for review! My answers, one question and new patch
below.

On 10/19/19 1:08 AM, Vladislav Shpilevoy wrote:
> Thanks for the patch!
>
> See 14 comments below.
>
> On 17/10/2019 16:40, imeevma@tarantool.org wrote:
>> This patch creates the _vsql_settings sysview. This system view
>> has custom methods get() and create_iterator(). This allows us
>> to get SQL settings by creating a tuple on the fly without having
>> to save it anywhere.
>>
>> Part of #4511
>>
>> @TarantoolBot document
>
> 1. I think, it is worth to create one doc request for the
> whole feature - both SET command and _vsql_settings space.
> They are useless without each other.
>
Fixed. However, do I need to write a doc-bot request now when the
sysview purpose has changed?

>> Title: The _vsql_settings sysview
>> Sysview _vsql_settings allows the user to get the current SQL
>> parameters.
>>
>> Currently available SQL settings:
>> 'defer_foreign_keys'
>> 'full_column_names'
>> 'recursive_triggers'
>> 'reverse_unordered_selects'
>> 'sql_compound_select_limit'
>> 'sql_default_engine'
>>
>> In addition, SQL debugging settings can also be obtained from this
>> system view in the debug build:
>> 'parser_trace'
>> 'select_trace'
>> 'sql_trace'
>> 'vdbe_addoptrace'
>> 'vdbe_debug'
>> 'vdbe_eqp'
>> 'vdbe_listing'
>> 'vdbe_trace'
>> 'where_trace'
>>
>> Example of usage:
>> box.space._vsql_settings:get{'full_column_names'}
>> box.space._vsql_settings:select{'defer_foreign_keys'}
>> box.space._vsql_settings:select{'full_column_names', {iterator = 'LE'}}
>
> 2. There is a problem with having generic iterators. Because if
> you allow to iterate over multiple settings, then you have
> to do it like normal indexes do, with a strict order. Currently
> you return settings without an order.
>
> There is 2 options what to do:
>
> - Ban all iterator types except =, and ban an empty key;
>
> - Keep the settings sorted and return them like a tree
>   index does. That might be useful in case we will agree
>   to create a generic space _vsession_storage. Then by a
>   prefix a user could select all settings of a specific
>   subsystem. Like 'sql_', 'vinyl_', etc.
>
> I am ok with both. Or maybe you will be able to find a third
> solution.
>
Fixed. I changed the order, now it works as the second option
suggested.

> Another problem is that: pairs() and select() somewhy return
> different results.
>
> tarantool> t = {}
> ---
> ...
>
> tarantool> for k, v in box.space._vsql_settings:pairs() do table.insert(t, {k, v}) end
> ---
> ...
>
> tarantool> t
> ---
> - - - <iterator state>
>     - ['defer_foreign_keys', false]
> ...
>
> tarantool> box.space._vsql_settings:select()
> ---
> - - ['defer_foreign_keys', false]
>   - ['full_column_names', false]
>   - ['recursive_triggers', true]
>   - ['reverse_unordered_selects', false]
>   - ['sql_compound_select_limit', 30]
>   - ['sql_default_engine', 'memtx']
>   - ['parser_trace', false]
>   - ['select_trace', false]
>   - ['sql_trace', false]
>   - ['vdbe_addoptrace', false]
>   - ['vdbe_debug', false]
>   - ['vdbe_eqp', false]
>   - ['vdbe_listing', false]
>   - ['vdbe_trace', false]
>   - ['where_trace', false]
> ...
>
> As you see, pairs() stops after a first tuple. For other spaces
> empty pairs and select work the same.
>
I fixed this, still not sure why it was like this - after I
rewritten the patch, it worked as it should.

>> ---
>>  src/box/bootstrap.snap             | Bin 5934 -> 5973 bytes
>>  src/box/lua/space.cc               |   2 +
>>  src/box/lua/upgrade.lua            |  23 +++++
>>  src/box/schema_def.h               |   2 +
>>  src/box/sql.c                      | 203 +++++++++++++++++++++++++++++++++++++
>>  src/box/sql.h                      |  66 ++++++++++++
>>  src/box/sql/sqlInt.h               |  14 +--
>>  src/box/sysview.c                  |  19 +++-
>>  test/app-tap/tarantoolctl.test.lua |   4 +-
>>  test/box-py/bootstrap.result       |   5 +-
>>  test/box/access_misc.result        | 136 +++++++++++++------------
>>  test/box/access_sysview.result     |   6 +-
>>  test/box/alter.result              |   5 +-
>>  test/box/sql.result                | 111 ++++++++++++++++++++
>>  test/box/sql.test.lua              |  38 +++++++
>>  test/wal_off/alter.result          |   2 +-
>>  16 files changed, 542 insertions(+), 94 deletions(-)
>>
>> diff --git a/src/box/lua/upgrade.lua b/src/box/lua/upgrade.lua
>> index 2abd75d..f105db8 100644
>> --- a/src/box/lua/upgrade.lua
>> +++ b/src/box/lua/upgrade.lua
>> @@ -930,6 +930,28 @@ local function upgrade_to_2_3_0()
>>  end
>>  
>>  --------------------------------------------------------------------------------
>> +-- Tarantool 2.3.1
>> +--------------------------------------------------------------------------------
>> +
>> +local function create_vsql_settings_sysview()
>> +    local _space = box.space[box.schema.SPACE_ID]
>> +    local _index = box.space[box.schema.INDEX_ID]
>> +    local format = {}
>> +    format[1] = {name='name', type='string'}
>> +    format[2] = {name='value', type='any'}
>> +    log.info("create space _vsql_settings")
>> +    _space:insert{box.schema.VSQL_SETTINGS_ID, ADMIN, '_vsql_settings',
>> +                  'sysview', 0, setmap({}), format}
>> +    log.info("create index _sql_settings:primary")
>
> 3. _vsql, not _sql
>
Fixed.

>> +    _index:insert{box.schema.VSQL_SETTINGS_ID, 0, 'primary', 'tree',
>
> 4. See? You said it is 'tree' and the key is string, but select() returns
> tuples in a mixed order:
>
>   - ['sql_default_engine', 'memtx']
>   - ['parser_trace', false]
>   - ['select_trace', false]
>
> 's', 'p', 's' - clearly not an alphabetical order.
>
Fixed.

>> +                  {unique = true}, {{0, 'string'}}}
>> +end
>> +
>> diff --git a/src/box/schema_def.h b/src/box/schema_def.h
>> index 85f652d..04e1e33 100644
>> --- a/src/box/schema_def.h
>> +++ b/src/box/schema_def.h
>> @@ -114,6 +114,8 @@ enum {
>>  	BOX_CK_CONSTRAINT_ID = 364,
>>  	/** Space id of _func_index. */
>>  	BOX_FUNC_INDEX_ID = 372,
>> +	/** Space id of _vsql_settings. */
>> +	BOX_VSQL_SETTINGS_ID = 380,
>
> 5. Usually system views are the original space ID + 1.
> So here it would be 381. Sorry for the nit.
>
Fixed.

>>  	/** End of the reserved range of system spaces. */
>>  	BOX_SYSTEM_ID_MAX = 511,
>>  	BOX_ID_NIL = 2147483647
>> diff --git a/src/box/sql.c b/src/box/sql.c
>> index f1df555..0c73caf 100644
>> --- a/src/box/sql.c
>> +++ b/src/box/sql.c
>> @@ -1265,3 +1265,206 @@ vdbe_field_ref_prepare_tuple(struct vdbe_field_ref *field_ref,
>>  	vdbe_field_ref_create(field_ref, tuple, tuple_data(tuple),
>>  			      tuple->bsize);
>>  }
>> +
>> +struct sql_option_metadata sql_options[] = {
>> +	/* SQL_OPTION_DEFER_FOREIGN_KEYS */
>> +	{"defer_foreign_keys", FIELD_TYPE_BOOLEAN, SQL_DeferFKs},
>> +	/* SQL_OPTION_DEFER_FOREIGN_KEYS */
>
> 6. Double SQL_OPTION_DEFER_FOREIGN_KEYS.
>
Fixed.

>> +	{"full_column_names", FIELD_TYPE_BOOLEAN, SQL_FullColNames},
>> +	/* SQL_OPTION_RECURSIVE_TRIGGERS */
>> +	{"recursive_triggers", FIELD_TYPE_BOOLEAN, SQL_RecTriggers},
>> +	/* SQL_OPTION_REVERSE_UNORDERED_SELECTS */
>> +	{"reverse_unordered_selects", FIELD_TYPE_BOOLEAN, SQL_ReverseOrder},
>> +	/* SQL_OPTION_COMPOUND_SELECT_LIMIT */
>> +	{"sql_compound_select_limit", FIELD_TYPE_INTEGER, 0},
>> +	/* SQL_OPTION_DEFAULT_ENGINE */
>> +	{"sql_default_engine", FIELD_TYPE_STRING, 0},
>> +	/* SQL_OPTION_PARSER_TRACE */
>> +	{"parser_trace", FIELD_TYPE_BOOLEAN, PARSER_TRACE_FLAG},
>> +	/* SQL_OPTION_SELECT_TRACE */
>> +	{"select_trace", FIELD_TYPE_BOOLEAN, SQL_SelectTrace},
>> +	/* SQL_OPTION_TRACE */
>> +	{"sql_trace", FIELD_TYPE_BOOLEAN, SQL_SqlTrace},
>> +	/* SQL_OPTION_VDBE_ADDOPTRACE */
>> +	{"vdbe_addoptrace", FIELD_TYPE_BOOLEAN, SQL_VdbeAddopTrace},
>> +	/* SQL_OPTION_VDBE_DEBUG */
>> +	{"vdbe_debug", FIELD_TYPE_BOOLEAN,
>> +	 SQL_SqlTrace | SQL_VdbeListing | SQL_VdbeTrace},
>> +	/* SQL_OPTION_VDBE_EQP */
>> +	{"vdbe_eqp", FIELD_TYPE_BOOLEAN, SQL_VdbeEQP},
>> +	/* SQL_OPTION_VDBE_LISTING */
>> +	{"vdbe_listing", FIELD_TYPE_BOOLEAN, SQL_VdbeListing},
>> +	/* SQL_OPTION_VDBE_TRACE */
>> +	{"vdbe_trace", FIELD_TYPE_BOOLEAN, SQL_VdbeTrace},
>> +	/* SQL_OPTION_WHERE_TRACE */
>> +	{"where_trace", FIELD_TYPE_BOOLEAN, SQL_WhereTrace},
>> +};
>> +
>> +static inline int
>> +sql_option_id_by_key(const char *key)
>
> 7. From the API it looks like the key is a normal string,
> but in fact it is a MessagePack encoded string. Please,
> say it somewhere in the function name/comment/parameter name.
>
Fixed. Now it takes name as string.

>> +{
>> +	uint32_t len;
>> +	struct region *region = &fiber()->gc;
>> +	size_t svp = region_used(region);
>> +	const char *tmp = mp_decode_str(&key, &len);
>> +	char *str = region_alloc(region, len + 1);
>
> 8. Please, use tt_cstr. It is much faster and simpler.
>
Thanks, fixed.

>> +	strncpy(str, tmp, len);
>> +	str[len] = '\0';
>> +	int id;
>> +	for (id = 0; id < SQL_OPTION_max; ++id) {
>> +		if (strcmp(str, sql_options[id].name) == 0)
>> +			break;
>> +	}
>> +	region_truncate(region, svp);
>> +	return id;
>> +}
>> +
>> +/**
>> + * Create tuple that contains name and value of the option.
>> + *
>> + * @param format format for new tuple.
>> + * @param option_id id of option to return.
>> + * @param result[out] new tuple.
>
> 9. Please, use capital letters in the sentences beginning.
>
Fixed.

> 10. [out] modifier stands right after param:
>
>         @param[out]
>
Fixed.

>> + */
>> +static int
>> +sql_option_tuple(struct tuple_format *format, int option_id,
>> +		 struct tuple **result)
>> +{
>> +	if (option_id < 0 || option_id >= SQL_OPTION_max) {
>> +		*result = NULL;
>> +		return 0;
>> +	}
>> +	int limit = 0;
>> +	const char *engine = NULL;
>> +	struct region *region = &fiber()->gc;
>> +	struct session *session = current_session();
>> +	uint32_t flags = session->sql_flags;
>> +	uint32_t option_flag = sql_options[option_id].flag;
>> +	/* Change to format->*_field_count */
>
> 11. Sorry, I didn't understand the comment. Change what? Why
> not to change now?
>
Sorry, I wrote this comment for myself but forgot about it.

>> +	uint32_t column_count = 2;
>> +	size_t size = mp_sizeof_array(column_count) +
>> +		      mp_sizeof_str(strlen(sql_options[option_id].name));
>> +	if (sql_options[option_id].field_type == FIELD_TYPE_BOOLEAN) {
>> +		size += mp_sizeof_bool(true);
>> +	} else if (option_id == SQL_OPTION_DEFAULT_ENGINE) {
>> +		engine = sql_storage_engine_strs[session->sql_default_engine];
>> +		size += mp_sizeof_str(strlen(engine));
>> +	} else {
>> +		assert(option_id == SQL_OPTION_COMPOUND_SELECT_LIMIT);
>> +		limit = sql_get()->aLimit[SQL_LIMIT_COMPOUND_SELECT];
>> +		size += mp_sizeof_uint(limit);
>> +	}
>> +
>> +	size_t svp = region_used(region);
>> +	char *pos_ret = region_alloc(region, size);
>> +	if (pos_ret == NULL) {
>> +		diag_set(OutOfMemory, size, "region_alloc", "pos_ret");
>> +		return -1;
>> +	}
>> +	char *pos = mp_encode_array(pos_ret, column_count);
>> +	pos = mp_encode_str(pos, sql_options[option_id].name,
>> +			    strlen(sql_options[option_id].name));
>> +	if (sql_options[option_id].field_type == FIELD_TYPE_BOOLEAN)
>> +		pos = mp_encode_bool(pos, (flags & option_flag) == option_flag);
>> +	else if (option_id == SQL_OPTION_DEFAULT_ENGINE)
>> +		pos = mp_encode_str(pos, engine, strlen(engine));
>> +	else
>> +		pos = mp_encode_uint(pos, limit);
>> +	struct tuple *tuple = tuple_new(format, pos_ret, pos_ret + size);
>> +	region_truncate(region, svp);
>> +	if (tuple == NULL)
>> +		return -1;
>> +	*result = tuple;
>> +	return 0;
>> +}
>> +
>> +int> +sql_options_get(struct index *index, const char *key, uint32_t part_count,
>> +		struct tuple **result)
>> +{
>> +	assert(part_count == 1);
>> +	(void)part_count;
>> +	struct space *space = space_cache_find(index->def->space_id);
>> +	uint32_t option_id = sql_option_id_by_key(key);
>> +	if (option_id == SQL_OPTION_max) {
>> +		*result = NULL;
>> +		return 0;
>> +	}
>> +	return sql_option_tuple(space->format, option_id, result);
>> +}
>> +
>> +struct sql_options_iterator {
>> +	struct iterator base;
>> +	struct tuple_format *format;
>> +	int option_id;
>> +	bool is_eq_type;
>> +	size_t svp;
>> +};
>> +
>> +static int
>> +sql_options_iterator_next(struct iterator *itr, struct tuple **ret)
>> +{
>> +	struct sql_options_iterator *it = (struct sql_options_iterator *)itr;
>> +	int rc = sql_option_tuple(it->format, it->option_id++, ret);
>> +	if (it->is_eq_type)
>> +		it->option_id = SQL_OPTION_max;
>> +	return rc;
>> +}
>> +
>> +static int
>> +sql_options_iterator_prev(struct iterator *itr, struct tuple **ret)
>> +{
>> +	struct sql_options_iterator *it = (struct sql_options_iterator *)itr;
>> +	int rc = sql_option_tuple(it->format, it->option_id--, ret);
>> +	if (it->is_eq_type)
>> +		it->option_id = -1;
>> +	return rc;
>> +}
>> +
>> +static void
>> +sql_options_iterator_free(struct iterator *itr)
>> +{
>> +	struct sql_options_iterator *it = (struct sql_options_iterator *)itr;
>> +	region_truncate(&fiber()->gc, it->svp);
>> +}
>> +
>> +struct iterator *
>> +sql_options_create_iterator(struct index *index, enum iterator_type type,
>> +			    const char *key, uint32_t part_count)
>> +{
>> +	bool is_eq_type = false;
>> +	uint32_t option_id;
>> +	if (part_count > 0) {
>> +		assert(part_count == 1);
>> +		option_id = sql_option_id_by_key(key);
>> +		if (type == ITER_EQ || type == ITER_REQ)
>> +			is_eq_type = true;
>> +		else if (type == ITER_LT)
>> +			--option_id;
>> +		else if (type == ITER_GT)
>> +			++option_id;
>> +		if (option_id == SQL_OPTION_max && type == ITER_LE)
>> +			--option_id;
>> +	} else {
>> +		option_id = iterator_type_is_reverse(type) ?
>> +			    SQL_OPTION_max - 1 : 0;
>> +	}
>> +	struct space *space = space_cache_find(index->def->space_id);
>> +	struct region *region = &fiber()->gc;
>> +	size_t svp = region_used(region);
>> +	struct sql_options_iterator *it = region_alloc(region, sizeof(*it));
>
> 12. Unfortunately, you can't allocate iterators on a
> region - iterators should survive fiber garbage
> collection.
>
Fixed, replaced by malloc.

>> +	if (it == NULL) {
>> +		diag_set(OutOfMemory, sizeof(*it), "region_alloc", "it");
>> +		return NULL;
>> +	}
>> +	iterator_create(&it->base, index);
>> +	it->base.next = iterator_type_is_reverse(type) ?
>> +			sql_options_iterator_prev :
>> +			sql_options_iterator_next;
>> +	it->base.free = sql_options_iterator_free;
>> +	it->option_id = option_id;
>> +	it->is_eq_type = is_eq_type;
>> +	it->format = space->format;
>> +	it->svp = svp;
>> +	return (struct iterator *)it;
>> +}
>> diff --git a/src/box/sql.h b/src/box/sql.h
>> index 0fa52fc..5c23748 100644
>> --- a/src/box/sql.h
>> +++ b/src/box/sql.h
>> @@ -33,11 +33,68 @@
>>  
>>  #include <stdbool.h>
>>  #include <stdint.h>
>> +#include "iterator_type.h"
>>  
>>  #if defined(__cplusplus)
>>  extern "C" {
>>  #endif
>>  
>> +/** SQL options flags. */
>> +/** True to trace VDBE execution */
>> +#define SQL_VdbeTrace		0x00000001
>> +/** Debug print info about SQL query as it parsed */
>> +#define PARSER_TRACE_FLAG	0x00000002
>> +/** Show full column names on SELECT */
>> +#define SQL_FullColNames	0x00000004
>> +/** Debug print SQL as it executes */
>> +#define SQL_SqlTrace		0x00000200
>> +/** Debug info about select statement */
>> +#define SQL_SelectTrace		0x00000800
>> +/** Debug info about optimizer's work */
>> +#define SQL_WhereTrace		0x00008000
>> +/** Debug listings of VDBE programs */
>> +#define SQL_VdbeListing		0x00000400
>> +/** Trace sqlVdbeAddOp() calls */
>> +#define SQL_VdbeAddopTrace	0x00001000
>> +/** Reverse unordered SELECTs */
>> +#define SQL_ReverseOrder	0x00020000
>> +/** Enable recursive triggers */
>> +#define SQL_RecTriggers		0x00040000
>> +/** Defer all FK constraints */
>> +#define SQL_DeferFKs		0x02000000
>> +/** Debug EXPLAIN QUERY PLAN */
>> +#define SQL_VdbeEQP		0x08000000
>
> 13. Why have you moved these macros from their old
> place?
>
Fixed.

>> +
>> +enum {
>> +	SQL_OPTION_DEFER_FOREIGN_KEYS = 0,
>> +	SQL_OPTION_FULL_COLUMN_NAMES,
>> +	SQL_OPTION_RECURSIVE_TRIGGERS,
>> +	SQL_OPTION_REVERSE_UNORDERED_SELECTS,
>> +	SQL_OPTION_COMPOUND_SELECT_LIMIT,
>> +	SQL_OPTION_DEFAULT_ENGINE,
>> +#ifndef NDEBUG> diff --git a/test/box/access_misc.result b/test/box/access_misc.result
>> index a1b6435..66469e1 100644
>> --- a/test/box/access_misc.result
>> +++ b/test/box/access_misc.result
>> @@ -835,144 +835,146 @@ box.space._space:select()
>>        {'name': 'language', 'type': 'str'}, {'name': 'code', 'type': 'str'}]]
>>    - [372, 1, '_func_index', 'memtx', 0, {}, [{'name': 'space_id', 'type': 'unsigned'},
>>        {'name': 'index_id', 'type': 'unsigned'}, {'name': 'func_id', 'type': 'unsigned'}]]
>> +  - [380, 1, '_vsql_settings', 'sysview', 0, {}, [{'name': 'name', 'type': 'string'},
>> +      {'name': 'value', 'type': 'any'}]]
>>  ...
>>  box.space._func:select()
>>  ---
>>  - - [1, 1, 'box.schema.user.info', 1, 'LUA', '', 'function', [], 'any', 'none', 'none',
>> -    false, false, true, ['LUA'], {}, '', '2019-08-14 14:09:37', '2019-08-14 14:09:37']
>> +    false, false, true, ['LUA'], {}, '', '2019-10-16 15:38:07', '2019-10-16 15:38:07']
>>    - [2, 1, 'TRIM', 1, 'SQL_BUILTIN', '', 'function', [], 'any', 'none', 'none', false,
>> -    false, true, [], {}, '', '2019-08-14 14:09:37', '2019-08-14 14:09:37']
>> +    false, true, [], {}, '', '2019-10-16 15:38:07', '2019-10-16 15:38:07']
>>    - [3, 1, 'TYPEOF', 1, 'SQL_BUILTIN', '', 'function', [], 'any', 'none', 'none',
>> -    false, false, true, [], {}, '', '2019-08-14 14:09:37', '2019-08-14 14:09:37']
>> +    false, false, true, [], {}, '', '2019-10-16 15:38:07', '2019-10-16 15:38:07']
>>    - [4, 1, 'PRINTF', 1, 'SQL_BUILTIN', '', 'function', [], 'any', 'none', 'none',
>> -    false, false, true, [], {}, '', '2019-08-14 14:09:37', '2019-08-14 14:09:37']
>> +    false, false, true, [], {}, '', '2019-10-16 15:38:07', '2019-10-16 15:38:07']
>>    - [5, 1, 'UNICODE', 1, 'SQL_BUILTIN', '', 'function', [], 'any', 'none', 'none',
>> -    false, false, true, [], {}, '', '2019-08-14 14:09:37', '2019-08-14 14:09:37']
>> +    false, false, true, [], {}, '', '2019-10-16 15:38:07', '2019-10-16 15:38:07']
>>    - [6, 1, 'CHAR', 1, 'SQL_BUILTIN', '', 'function', [], 'any', 'none', 'none', false,
>> -    false, true, [], {}, '', '2019-08-14 14:09:37', '2019-08-14 14:09:37']
>> +    false, true, [], {}, '', '2019-10-16 15:38:07', '2019-10-16 15:38:07']
>>    - [7, 1, 'HEX', 1, 'SQL_BUILTIN', '', 'function', [], 'any', 'none', 'none', false,
>> -    false, true, [], {}, '', '2019-08-14 14:09:37', '2019-08-14 14:09:37']
>> +    false, true, [], {}, '', '2019-10-16 15:38:07', '2019-10-16 15:38:07']
>>    - [8, 1, 'VERSION', 1, 'SQL_BUILTIN', '', 'function', [], 'any', 'none', 'none',
>> -    false, false, true, [], {}, '', '2019-08-14 14:09:37', '2019-08-14 14:09:37']
>> +    false, false, true, [], {}, '', '2019-10-16 15:38:07', '2019-10-16 15:38:07']
>>    - [9, 1, 'QUOTE', 1, 'SQL_BUILTIN', '', 'function', [], 'any', 'none', 'none', false,
>> -    false, true, [], {}, '', '2019-08-14 14:09:37', '2019-08-14 14:09:37']
>> +    false, true, [], {}, '', '2019-10-16 15:38:07', '2019-10-16 15:38:07']
>>    - [10, 1, 'REPLACE', 1, 'SQL_BUILTIN', '', 'function', [], 'any', 'none', 'none',
>> -    false, false, true, [], {}, '', '2019-08-14 14:09:37', '2019-08-14 14:09:37']
>> +    false, false, true, [], {}, '', '2019-10-16 15:38:07', '2019-10-16 15:38:07']
>>    - [11, 1, 'SUBSTR', 1, 'SQL_BUILTIN', '', 'function', [], 'any', 'none', 'none',
>> -    false, false, true, [], {}, '', '2019-08-14 14:09:37', '2019-08-14 14:09:37']
>> +    false, false, true, [], {}, '', '2019-10-16 15:38:07', '2019-10-16 15:38:07']
>>    - [12, 1, 'GROUP_CONCAT', 1, 'SQL_BUILTIN', '', 'function', [], 'any', 'none', 'none',
>> -    false, false, true, [], {}, '', '2019-08-14 14:09:37', '2019-08-14 14:09:37']
>> +    false, false, true, [], {}, '', '2019-10-16 15:38:07', '2019-10-16 15:38:07']
>>    - [13, 1, 'JULIANDAY', 1, 'SQL_BUILTIN', '', 'function', [], 'any', 'none', 'none',
>> -    false, false, true, [], {}, '', '2019-08-14 14:09:37', '2019-08-14 14:09:37']
>> +    false, false, true, [], {}, '', '2019-10-16 15:38:07', '2019-10-16 15:38:07']
>>    - [14, 1, 'DATE', 1, 'SQL_BUILTIN', '', 'function', [], 'any', 'none', 'none', false,
>> -    false, true, [], {}, '', '2019-08-14 14:09:37', '2019-08-14 14:09:37']
>> +    false, true, [], {}, '', '2019-10-16 15:38:07', '2019-10-16 15:38:07']
>>    - [15, 1, 'TIME', 1, 'SQL_BUILTIN', '', 'function', [], 'any', 'none', 'none', false,
>> -    false, true, [], {}, '', '2019-08-14 14:09:37', '2019-08-14 14:09:37']
>> +    false, true, [], {}, '', '2019-10-16 15:38:07', '2019-10-16 15:38:07']
>>    - [16, 1, 'DATETIME', 1, 'SQL_BUILTIN', '', 'function', [], 'any', 'none', 'none',
>> -    false, false, true, [], {}, '', '2019-08-14 14:09:37', '2019-08-14 14:09:37']
>> +    false, false, true, [], {}, '', '2019-10-16 15:38:07', '2019-10-16 15:38:07']
>>    - [17, 1, 'STRFTIME', 1, 'SQL_BUILTIN', '', 'function', [], 'any', 'none', 'none',
>> -    false, false, true, [], {}, '', '2019-08-14 14:09:37', '2019-08-14 14:09:37']
>> +    false, false, true, [], {}, '', '2019-10-16 15:38:07', '2019-10-16 15:38:07']
>>    - [18, 1, 'CURRENT_TIME', 1, 'SQL_BUILTIN', '', 'function', [], 'any', 'none', 'none',
>> -    false, false, true, [], {}, '', '2019-08-14 14:09:37', '2019-08-14 14:09:37']
>> +    false, false, true, [], {}, '', '2019-10-16 15:38:07', '2019-10-16 15:38:07']
>>    - [19, 1, 'CURRENT_TIMESTAMP', 1, 'SQL_BUILTIN', '', 'function', [], 'any', 'none',
>> -    'none', false, false, true, [], {}, '', '2019-08-14 14:09:37', '2019-08-14 14:09:37']
>> +    'none', false, false, true, [], {}, '', '2019-10-16 15:38:07', '2019-10-16 15:38:07']
>>    - [20, 1, 'CURRENT_DATE', 1, 'SQL_BUILTIN', '', 'function', [], 'any', 'none', 'none',
>> -    false, false, true, [], {}, '', '2019-08-14 14:09:37', '2019-08-14 14:09:37']
>> +    false, false, true, [], {}, '', '2019-10-16 15:38:07', '2019-10-16 15:38:07']
>>    - [21, 1, 'LENGTH', 1, 'SQL_BUILTIN', '', 'function', [], 'any', 'none', 'none',
>> -    false, false, true, [], {}, '', '2019-08-14 14:09:37', '2019-08-14 14:09:37']
>> +    false, false, true, [], {}, '', '2019-10-16 15:38:07', '2019-10-16 15:38:07']
>>    - [22, 1, 'POSITION', 1, 'SQL_BUILTIN', '', 'function', [], 'any', 'none', 'none',
>> -    false, false, true, [], {}, '', '2019-08-14 14:09:37', '2019-08-14 14:09:37']
>> +    false, false, true, [], {}, '', '2019-10-16 15:38:07', '2019-10-16 15:38:07']
>>    - [23, 1, 'ROUND', 1, 'SQL_BUILTIN', '', 'function', [], 'any', 'none', 'none',
>> -    false, false, true, [], {}, '', '2019-08-14 14:09:37', '2019-08-14 14:09:37']
>> +    false, false, true, [], {}, '', '2019-10-16 15:38:07', '2019-10-16 15:38:07']
>>    - [24, 1, 'UPPER', 1, 'SQL_BUILTIN', '', 'function', [], 'any', 'none', 'none',
>> -    false, false, true, [], {}, '', '2019-08-14 14:09:37', '2019-08-14 14:09:37']
>> +    false, false, true, [], {}, '', '2019-10-16 15:38:07', '2019-10-16 15:38:07']
>>    - [25, 1, 'LOWER', 1, 'SQL_BUILTIN', '', 'function', [], 'any', 'none', 'none',
>> -    false, false, true, [], {}, '', '2019-08-14 14:09:37', '2019-08-14 14:09:37']
>> +    false, false, true, [], {}, '', '2019-10-16 15:38:07', '2019-10-16 15:38:07']
>>    - [26, 1, 'IFNULL', 1, 'SQL_BUILTIN', '', 'function', [], 'any', 'none', 'none',
>> -    false, false, true, [], {}, '', '2019-08-14 14:09:37', '2019-08-14 14:09:37']
>> +    false, false, true, [], {}, '', '2019-10-16 15:38:07', '2019-10-16 15:38:07']
>>    - [27, 1, 'RANDOM', 1, 'SQL_BUILTIN', '', 'function', [], 'any', 'none', 'none',
>> -    false, false, true, [], {}, '', '2019-08-14 14:09:37', '2019-08-14 14:09:37']
>> +    false, false, true, [], {}, '', '2019-10-16 15:38:07', '2019-10-16 15:38:07']
>>    - [28, 1, 'CEIL', 1, 'SQL_BUILTIN', '', 'function', [], 'any', 'none', 'none', false,
>> -    false, true, [], {}, '', '2019-08-14 14:09:37', '2019-08-14 14:09:37']
>> +    false, true, [], {}, '', '2019-10-16 15:38:07', '2019-10-16 15:38:07']
>>    - [29, 1, 'CEILING', 1, 'SQL_BUILTIN', '', 'function', [], 'any', 'none', 'none',
>> -    false, false, true, [], {}, '', '2019-08-14 14:09:37', '2019-08-14 14:09:37']
>> +    false, false, true, [], {}, '', '2019-10-16 15:38:07', '2019-10-16 15:38:07']
>>    - [30, 1, 'CHARACTER_LENGTH', 1, 'SQL_BUILTIN', '', 'function', [], 'any', 'none',
>> -    'none', false, false, true, [], {}, '', '2019-08-14 14:09:37', '2019-08-14 14:09:37']
>> +    'none', false, false, true, [], {}, '', '2019-10-16 15:38:07', '2019-10-16 15:38:07']
>>    - [31, 1, 'CHAR_LENGTH', 1, 'SQL_BUILTIN', '', 'function', [], 'any', 'none', 'none',
>> -    false, false, true, [], {}, '', '2019-08-14 14:09:37', '2019-08-14 14:09:37']
>> +    false, false, true, [], {}, '', '2019-10-16 15:38:07', '2019-10-16 15:38:07']
>>    - [32, 1, 'FLOOR', 1, 'SQL_BUILTIN', '', 'function', [], 'any', 'none', 'none',
>> -    false, false, true, [], {}, '', '2019-08-14 14:09:37', '2019-08-14 14:09:37']
>> +    false, false, true, [], {}, '', '2019-10-16 15:38:07', '2019-10-16 15:38:07']
>>    - [33, 1, 'MOD', 1, 'SQL_BUILTIN', '', 'function', [], 'any', 'none', 'none', false,
>> -    false, true, [], {}, '', '2019-08-14 14:09:37', '2019-08-14 14:09:37']
>> +    false, true, [], {}, '', '2019-10-16 15:38:07', '2019-10-16 15:38:07']
>>    - [34, 1, 'OCTET_LENGTH', 1, 'SQL_BUILTIN', '', 'function', [], 'any', 'none', 'none',
>> -    false, false, true, [], {}, '', '2019-08-14 14:09:37', '2019-08-14 14:09:37']
>> +    false, false, true, [], {}, '', '2019-10-16 15:38:07', '2019-10-16 15:38:07']
>>    - [35, 1, 'ROW_COUNT', 1, 'SQL_BUILTIN', '', 'function', [], 'any', 'none', 'none',
>> -    false, false, true, [], {}, '', '2019-08-14 14:09:37', '2019-08-14 14:09:37']
>> +    false, false, true, [], {}, '', '2019-10-16 15:38:07', '2019-10-16 15:38:07']
>>    - [36, 1, 'COUNT', 1, 'SQL_BUILTIN', '', 'function', [], 'any', 'none', 'none',
>> -    false, false, true, [], {}, '', '2019-08-14 14:09:37', '2019-08-14 14:09:37']
>> +    false, false, true, [], {}, '', '2019-10-16 15:38:07', '2019-10-16 15:38:07']
>>    - [37, 1, 'LIKE', 1, 'SQL_BUILTIN', '', 'function', [], 'any', 'none', 'none', false,
>> -    false, true, [], {}, '', '2019-08-14 14:09:37', '2019-08-14 14:09:37']
>> +    false, true, [], {}, '', '2019-10-16 15:38:07', '2019-10-16 15:38:07']
>>    - [38, 1, 'ABS', 1, 'SQL_BUILTIN', '', 'function', [], 'any', 'none', 'none', false,
>> -    false, true, [], {}, '', '2019-08-14 14:09:37', '2019-08-14 14:09:37']
>> +    false, true, [], {}, '', '2019-10-16 15:38:07', '2019-10-16 15:38:07']
>>    - [39, 1, 'EXP', 1, 'SQL_BUILTIN', '', 'function', [], 'any', 'none', 'none', false,
>> -    false, true, [], {}, '', '2019-08-14 14:09:37', '2019-08-14 14:09:37']
>> +    false, true, [], {}, '', '2019-10-16 15:38:07', '2019-10-16 15:38:07']
>>    - [40, 1, 'LN', 1, 'SQL_BUILTIN', '', 'function', [], 'any', 'none', 'none', false,
>> -    false, true, [], {}, '', '2019-08-14 14:09:37', '2019-08-14 14:09:37']
>> +    false, true, [], {}, '', '2019-10-16 15:38:07', '2019-10-16 15:38:07']
>>    - [41, 1, 'POWER', 1, 'SQL_BUILTIN', '', 'function', [], 'any', 'none', 'none',
>> -    false, false, true, [], {}, '', '2019-08-14 14:09:37', '2019-08-14 14:09:37']
>> +    false, false, true, [], {}, '', '2019-10-16 15:38:07', '2019-10-16 15:38:07']
>>    - [42, 1, 'SQRT', 1, 'SQL_BUILTIN', '', 'function', [], 'any', 'none', 'none', false,
>> -    false, true, [], {}, '', '2019-08-14 14:09:37', '2019-08-14 14:09:37']
>> +    false, true, [], {}, '', '2019-10-16 15:38:07', '2019-10-16 15:38:07']
>>    - [43, 1, 'SUM', 1, 'SQL_BUILTIN', '', 'function', [], 'any', 'none', 'none', false,
>> -    false, true, [], {}, '', '2019-08-14 14:09:37', '2019-08-14 14:09:37']
>> +    false, true, [], {}, '', '2019-10-16 15:38:07', '2019-10-16 15:38:07']
>>    - [44, 1, 'TOTAL', 1, 'SQL_BUILTIN', '', 'function', [], 'any', 'none', 'none',
>> -    false, false, true, [], {}, '', '2019-08-14 14:09:37', '2019-08-14 14:09:37']
>> +    false, false, true, [], {}, '', '2019-10-16 15:38:07', '2019-10-16 15:38:07']
>>    - [45, 1, 'AVG', 1, 'SQL_BUILTIN', '', 'function', [], 'any', 'none', 'none', false,
>> -    false, true, [], {}, '', '2019-08-14 14:09:37', '2019-08-14 14:09:37']
>> +    false, true, [], {}, '', '2019-10-16 15:38:07', '2019-10-16 15:38:07']
>>    - [46, 1, 'RANDOMBLOB', 1, 'SQL_BUILTIN', '', 'function', [], 'any', 'none', 'none',
>> -    false, false, true, [], {}, '', '2019-08-14 14:09:37', '2019-08-14 14:09:37']
>> +    false, false, true, [], {}, '', '2019-10-16 15:38:07', '2019-10-16 15:38:07']
>>    - [47, 1, 'NULLIF', 1, 'SQL_BUILTIN', '', 'function', [], 'any', 'none', 'none',
>> -    false, false, true, [], {}, '', '2019-08-14 14:09:37', '2019-08-14 14:09:37']
>> +    false, false, true, [], {}, '', '2019-10-16 15:38:07', '2019-10-16 15:38:07']
>>    - [48, 1, 'ZEROBLOB', 1, 'SQL_BUILTIN', '', 'function', [], 'any', 'none', 'none',
>> -    false, false, true, [], {}, '', '2019-08-14 14:09:37', '2019-08-14 14:09:37']
>> +    false, false, true, [], {}, '', '2019-10-16 15:38:07', '2019-10-16 15:38:07']
>>    - [49, 1, 'MIN', 1, 'SQL_BUILTIN', '', 'function', [], 'any', 'none', 'none', false,
>> -    false, true, [], {}, '', '2019-08-14 14:09:37', '2019-08-14 14:09:37']
>> +    false, true, [], {}, '', '2019-10-16 15:38:07', '2019-10-16 15:38:07']
>>    - [50, 1, 'MAX', 1, 'SQL_BUILTIN', '', 'function', [], 'any', 'none', 'none', false,
>> -    false, true, [], {}, '', '2019-08-14 14:09:37', '2019-08-14 14:09:37']
>> +    false, true, [], {}, '', '2019-10-16 15:38:07', '2019-10-16 15:38:07']
>>    - [51, 1, 'COALESCE', 1, 'SQL_BUILTIN', '', 'function', [], 'any', 'none', 'none',
>> -    false, false, true, [], {}, '', '2019-08-14 14:09:37', '2019-08-14 14:09:37']
>> +    false, false, true, [], {}, '', '2019-10-16 15:38:07', '2019-10-16 15:38:07']
>>    - [52, 1, 'EVERY', 1, 'SQL_BUILTIN', '', 'function', [], 'any', 'none', 'none',
>> -    false, false, true, [], {}, '', '2019-08-14 14:09:37', '2019-08-14 14:09:37']
>> +    false, false, true, [], {}, '', '2019-10-16 15:38:07', '2019-10-16 15:38:07']
>>    - [53, 1, 'EXISTS', 1, 'SQL_BUILTIN', '', 'function', [], 'any', 'none', 'none',
>> -    false, false, true, [], {}, '', '2019-08-14 14:09:37', '2019-08-14 14:09:37']
>> +    false, false, true, [], {}, '', '2019-10-16 15:38:07', '2019-10-16 15:38:07']
>>    - [54, 1, 'EXTRACT', 1, 'SQL_BUILTIN', '', 'function', [], 'any', 'none', 'none',
>> -    false, false, true, [], {}, '', '2019-08-14 14:09:37', '2019-08-14 14:09:37']
>> +    false, false, true, [], {}, '', '2019-10-16 15:38:07', '2019-10-16 15:38:07']
>>    - [55, 1, 'SOME', 1, 'SQL_BUILTIN', '', 'function', [], 'any', 'none', 'none', false,
>> -    false, true, [], {}, '', '2019-08-14 14:09:37', '2019-08-14 14:09:37']
>> +    false, true, [], {}, '', '2019-10-16 15:38:07', '2019-10-16 15:38:07']
>>    - [56, 1, 'GREATER', 1, 'SQL_BUILTIN', '', 'function', [], 'any', 'none', 'none',
>> -    false, false, true, [], {}, '', '2019-08-14 14:09:37', '2019-08-14 14:09:37']
>> +    false, false, true, [], {}, '', '2019-10-16 15:38:07', '2019-10-16 15:38:07']
>>    - [57, 1, 'LESSER', 1, 'SQL_BUILTIN', '', 'function', [], 'any', 'none', 'none',
>> -    false, false, true, [], {}, '', '2019-08-14 14:09:37', '2019-08-14 14:09:37']
>> +    false, false, true, [], {}, '', '2019-10-16 15:38:07', '2019-10-16 15:38:07']
>>    - [58, 1, 'SOUNDEX', 1, 'SQL_BUILTIN', '', 'function', [], 'any', 'none', 'none',
>> -    false, false, true, [], {}, '', '2019-08-14 14:09:37', '2019-08-14 14:09:37']
>> +    false, false, true, [], {}, '', '2019-10-16 15:38:07', '2019-10-16 15:38:07']
>>    - [59, 1, 'LIKELIHOOD', 1, 'SQL_BUILTIN', '', 'function', [], 'any', 'none', 'none',
>> -    false, false, true, [], {}, '', '2019-08-14 14:09:37', '2019-08-14 14:09:37']
>> +    false, false, true, [], {}, '', '2019-10-16 15:38:07', '2019-10-16 15:38:07']
>>    - [60, 1, 'LIKELY', 1, 'SQL_BUILTIN', '', 'function', [], 'any', 'none', 'none',
>> -    false, false, true, [], {}, '', '2019-08-14 14:09:37', '2019-08-14 14:09:37']
>> +    false, false, true, [], {}, '', '2019-10-16 15:38:07', '2019-10-16 15:38:07']
>>    - [61, 1, 'UNLIKELY', 1, 'SQL_BUILTIN', '', 'function', [], 'any', 'none', 'none',
>> -    false, false, true, [], {}, '', '2019-08-14 14:09:37', '2019-08-14 14:09:37']
>> +    false, false, true, [], {}, '', '2019-10-16 15:38:07', '2019-10-16 15:38:07']
>>    - [62, 1, '_sql_stat_get', 1, 'SQL_BUILTIN', '', 'function', [], 'any', 'none',
>> -    'none', false, false, true, [], {}, '', '2019-08-14 14:09:37', '2019-08-14 14:09:37']
>> +    'none', false, false, true, [], {}, '', '2019-10-16 15:38:07', '2019-10-16 15:38:07']
>>    - [63, 1, '_sql_stat_push', 1, 'SQL_BUILTIN', '', 'function', [], 'any', 'none',
>> -    'none', false, false, true, [], {}, '', '2019-08-14 14:09:37', '2019-08-14 14:09:37']
>> +    'none', false, false, true, [], {}, '', '2019-10-16 15:38:07', '2019-10-16 15:38:07']
>>    - [64, 1, '_sql_stat_init', 1, 'SQL_BUILTIN', '', 'function', [], 'any', 'none',
>> -    'none', false, false, true, [], {}, '', '2019-08-14 14:09:37', '2019-08-14 14:09:37']
>> +    'none', false, false, true, [], {}, '', '2019-10-16 15:38:07', '2019-10-16 15:38:07']
>>    - [65, 1, 'LUA', 1, 'LUA', 'function(code) return assert(loadstring(code))() end',
>>      'function', ['string'], 'any', 'none', 'none', false, false, true, ['LUA', 'SQL'],
>> -    {}, '', '2019-08-14 14:09:37', '2019-08-14 14:09:37']
>> +    {}, '', '2019-10-16 15:38:07', '2019-10-16 15:38:07']
>>    - [66, 1, 'GREATEST', 1, 'SQL_BUILTIN', '', 'function', [], 'any', 'none', 'none',
>> -    false, false, true, [], {}, '', '2019-08-14 14:09:37', '2019-08-14 14:09:37']
>> +    false, false, true, [], {}, '', '2019-10-16 15:38:07', '2019-10-16 15:38:07']
>>    - [67, 1, 'LEAST', 1, 'SQL_BUILTIN', '', 'function', [], 'any', 'none', 'none',
>> -    false, false, true, [], {}, '', '2019-08-14 14:09:37', '2019-08-14 14:09:37']
>> +    false, false, true, [], {}, '', '2019-10-16 15:38:07', '2019-10-16 15:38:07']
>>  ...
>
> 14. Could we somehow refactor that test so as it would not change
> so much on each change of the schema? In a separate commit/branch.
>
Send a patch.


New patch:

From da4508c0b2f0b6af680163e6ae517200e7a9949f Mon Sep 17 00:00:00 2001
From: Mergen Imeev <imeevma@gmail.com>
Date: Thu, 24 Oct 2019 15:18:09 +0300
Subject: [PATCH] box: introdice _vsession_settings sysview

This patch creates the _vsession_settings sysview. This sysview
contains names and values of the session-local options.

This sysview creates tuples on the fly using its own get() and
create_iterator() methods. This allows us to get a tuple without
having to save it anywhere.

Currently, only SQL options can be extracted from this sysview,
since the only session-local options are SQL options.

Part of #4511

diff --git a/src/box/bootstrap.snap b/src/box/bootstrap.snap
index 59f6cc1..6b4b96a 100644
Binary files a/src/box/bootstrap.snap and b/src/box/bootstrap.snap differ
diff --git a/src/box/lua/space.cc b/src/box/lua/space.cc
index 8b84e1f..77f245c 100644
--- a/src/box/lua/space.cc
+++ b/src/box/lua/space.cc
@@ -652,6 +652,8 @@ box_lua_space_init(struct lua_State *L)
 	lua_setfield(L, -2, "SPACE_SEQUENCE_ID");
 	lua_pushnumber(L, BOX_FUNC_INDEX_ID);
 	lua_setfield(L, -2, "FUNC_INDEX_ID");
+	lua_pushnumber(L, BOX_VSESSION_SETTINGS_ID);
+	lua_setfield(L, -2, "VSESSION_SETTINGS_ID");
 	lua_pushnumber(L, BOX_SYSTEM_ID_MIN);
 	lua_setfield(L, -2, "SYSTEM_ID_MIN");
 	lua_pushnumber(L, BOX_SYSTEM_ID_MAX);
diff --git a/src/box/lua/upgrade.lua b/src/box/lua/upgrade.lua
index e71b7fb..94e4118 100644
--- a/src/box/lua/upgrade.lua
+++ b/src/box/lua/upgrade.lua
@@ -943,6 +943,28 @@ local function upgrade_to_2_3_0()
 end
 
 --------------------------------------------------------------------------------
+-- Tarantool 2.3.1
+--------------------------------------------------------------------------------
+
+local function create_vsession_settings_sysview()
+    local _space = box.space[box.schema.SPACE_ID]
+    local _index = box.space[box.schema.INDEX_ID]
+    local format = {}
+    format[1] = {name='name', type='string'}
+    format[2] = {name='value', type='any'}
+    log.info("create space _vsession_settings")
+    _space:insert{box.schema.VSESSION_SETTINGS_ID, ADMIN, '_vsession_settings',
+                  'sysview', 0, setmap({}), format}
+    log.info("create index _vsession_settings:primary")
+    _index:insert{box.schema.VSESSION_SETTINGS_ID, 0, 'primary', 'tree',
+                  {unique = true}, {{0, 'string'}}}
+end
+
+local function upgrade_to_2_3_1()
+    create_vsession_settings_sysview()
+end
+
+--------------------------------------------------------------------------------
 
 local function get_version()
     local version = box.space._schema:get{'version'}
@@ -977,6 +999,7 @@ local function upgrade(options)
         {version = mkversion(2, 1, 3), func = upgrade_to_2_1_3, auto = true},
         {version = mkversion(2, 2, 1), func = upgrade_to_2_2_1, auto = true},
         {version = mkversion(2, 3, 0), func = upgrade_to_2_3_0, auto = true},
+        {version = mkversion(2, 3, 1), func = upgrade_to_2_3_1, auto = true},
     }
 
     for _, handler in ipairs(handlers) do
diff --git a/src/box/schema_def.h b/src/box/schema_def.h
index ba870ff..b9824cb 100644
--- a/src/box/schema_def.h
+++ b/src/box/schema_def.h
@@ -114,6 +114,8 @@ enum {
 	BOX_CK_CONSTRAINT_ID = 364,
 	/** Space id of _func_index. */
 	BOX_FUNC_INDEX_ID = 372,
+	/** Space id of _vsession_settings. */
+	BOX_VSESSION_SETTINGS_ID = 381,
 	/** End of the reserved range of system spaces. */
 	BOX_SYSTEM_ID_MAX = 511,
 	BOX_ID_NIL = 2147483647
diff --git a/src/box/session.cc b/src/box/session.cc
index 59bf226..32dc87a 100644
--- a/src/box/session.cc
+++ b/src/box/session.cc
@@ -36,6 +36,9 @@
 #include "user.h"
 #include "error.h"
 #include "tt_static.h"
+#include "index.h"
+#include "schema.h"
+#include "sql.h"
 
 const char *session_type_strs[] = {
 	"background",
@@ -360,3 +363,116 @@ generic_session_sync(struct session *session)
 	(void) session;
 	return 0;
 }
+
+int
+session_options_get(struct index *index, const char *key, uint32_t part_count,
+		    struct tuple **result)
+{
+	assert(part_count == 1);
+	(void)part_count;
+	struct space *space = space_cache_find(index->def->space_id);
+	uint32_t len;
+	const char *name = mp_decode_str(&key, &len);
+	name = tt_cstr(name, len);
+	/*
+	 * Currently, the only session local options are SQL
+	 * options.
+	 */
+	uint32_t sql_option_id = sql_option_id_by_name(name);
+	return sql_option_tuple(space->format, sql_option_id, result);
+}
+
+/**
+ * An iterator that iterates over current session options.
+ */
+struct session_options_iterator {
+	/** Base iterator. Must be the first member. */
+	struct iterator base;
+	/** Format of the tuples this iterator returns. */
+	struct tuple_format *format;
+	/** Id of SQL option this iterator should return. */
+	uint32_t sql_option_id;
+	/**
+	 * The number of tuples left to show. If we did not get
+	 * the key when creating the iterator, then the value of
+	 * the field is < 0. Otherwise, it should be either 1 or 0
+	 * in the normal case.
+	 */
+	int max_tuples_to_show;
+};
+
+static int
+session_options_iterator_next(struct iterator *itr, struct tuple **ret)
+{
+	struct session_options_iterator *it =
+		(struct session_options_iterator *)itr;
+	if (it->max_tuples_to_show == 0) {
+		*ret = NULL;
+		return 0;
+	}
+	if (it->max_tuples_to_show > 0)
+		it->max_tuples_to_show--;
+	return sql_option_tuple(it->format, it->sql_option_id++, ret);
+}
+
+static int
+session_options_iterator_prev(struct iterator *itr, struct tuple **ret)
+{
+	struct session_options_iterator *it =
+		(struct session_options_iterator *)itr;
+	if (it->max_tuples_to_show == 0) {
+		*ret = NULL;
+		return 0;
+	} else if (it->max_tuples_to_show > 0) {
+		it->max_tuples_to_show--;
+	}
+	return sql_option_tuple(it->format, it->sql_option_id--, ret);
+}
+
+static void
+session_options_iterator_free(struct iterator *itr)
+{
+	free(itr);
+}
+
+struct iterator *
+session_options_create_iterator(struct index *index, enum iterator_type type,
+				const char *key, uint32_t part_count)
+{
+	int max_tuples_to_show = -1;
+	uint32_t sql_option_id;
+	if (part_count > 0) {
+		assert(part_count == 1);
+		uint32_t len;
+		const char *name = mp_decode_str(&key, &len);
+		name = tt_cstr(name, len);
+		sql_option_id = sql_option_id_by_name(name);
+		if (type == ITER_EQ || type == ITER_REQ)
+			max_tuples_to_show = 1;
+		else if (type == ITER_LT)
+			--sql_option_id;
+		else if (type == ITER_GT)
+			++sql_option_id;
+		if (sql_option_id == sql_option_id_max() && type == ITER_LE)
+			--sql_option_id;
+	} else {
+		sql_option_id = iterator_type_is_reverse(type) ?
+				sql_option_id_max() - 1 : 0;
+	}
+	struct space *space = space_cache_find(index->def->space_id);
+	struct session_options_iterator *it =
+		(session_options_iterator *)malloc(sizeof(*it));
+	if (it == NULL) {
+		diag_set(OutOfMemory, sizeof(*it), "malloc", "it");
+		return NULL;
+	}
+	iterator_create(&it->base, index);
+	it->base.next = iterator_type_is_reverse(type) ?
+			session_options_iterator_prev :
+			session_options_iterator_next;
+	it->base.free = session_options_iterator_free;
+	it->sql_option_id = sql_option_id;
+	it->max_tuples_to_show = max_tuples_to_show;
+	it->format = space->format;
+	return (struct iterator *)it;
+}
diff --git a/src/box/session.h b/src/box/session.h
index 85a2d94..96d9ad0 100644
--- a/src/box/session.h
+++ b/src/box/session.h
@@ -36,12 +36,15 @@
 #include "fiber.h"
 #include "user.h"
 #include "authentication.h"
+#include "iterator_type.h"
 
 #if defined(__cplusplus)
 extern "C" {
 #endif /* defined(__cplusplus) */
 
 struct port;
+struct index;
+struct tuple;
 struct session_vtab;
 
 void
@@ -355,6 +358,16 @@ generic_session_fd(struct session *session);
 int64_t
 generic_session_sync(struct session *session);
 
+/** Method get() for _vsession_settings sysview. */
+int
+session_options_get(struct index *index, const char *key, uint32_t part_count,
+		    struct tuple **result);
+
+/** Method create_iterator() for _vsession_settings sysview. */
+struct iterator *
+session_options_create_iterator(struct index *index, enum iterator_type type,
+				const char *key, uint32_t part_count);
+
 #if defined(__cplusplus)
 } /* extern "C" */
 
diff --git a/src/box/sql.h b/src/box/sql.h
index 0fa52fc..fe7cb08 100644
--- a/src/box/sql.h
+++ b/src/box/sql.h
@@ -70,6 +70,7 @@ struct Select;
 struct Table;
 struct sql_trigger;
 struct space_def;
+struct tuple_format;
 
 /**
  * Perform parsing of provided expression. This is done by
@@ -420,6 +421,39 @@ void
 vdbe_field_ref_prepare_tuple(struct vdbe_field_ref *field_ref,
 			     struct tuple *tuple);
 
+/**
+ * Return the next number after the last SQL option.
+ *
+ * @retval Next number after the last SQL option.
+ */
+uint32_t
+sql_option_id_max();
+
+/**
+ * Return the SQL option ID with the given name. If there is no
+ * option with this name, a number is returned that is equal to
+ * the one returned by sql_option_id_max().
+ *
+ * @param name The name of the option.
+ * @retval Option ID.
+ */
+int
+sql_option_id_by_name(const char *name);
+
+/**
+ * Create a tuple that contains the name and value of the SQL
+ * option.
+ *
+ * @param format Format of the tuple.
+ * @param option_id ID of SQL option.
+ * @param[out] result New tuple or NULL.
+ * @retval 0 On success.
+ * @retval < 0 On error.
+ */
+int
+sql_option_tuple(struct tuple_format *format, int option_id,
+		 struct tuple **result);
+
 #if defined(__cplusplus)
 } /* extern "C" { */
 #endif
diff --git a/src/box/sql/build.c b/src/box/sql/build.c
index 51cd7ce..cb97106 100644
--- a/src/box/sql/build.c
+++ b/src/box/sql/build.c
@@ -48,6 +48,7 @@
 #include "vdbeInt.h"
 #include "tarantoolInt.h"
 #include "box/box.h"
+#include "box/tuple.h"
 #include "box/ck_constraint.h"
 #include "box/fk_constraint.h"
 #include "box/sequence.h"
@@ -3242,3 +3243,160 @@ sql_fieldno_by_name(struct Parse *parse_context, struct Expr *field_name,
 	*fieldno = i;
 	return 0;
 }
+
+/**
+ * Identifiers of all SQL options that can be viewed. The
+ * identifier of the option is equal to its place in the sorted
+ * list of options, which starts at 0.
+ *
+ * It is IMPORTANT that SQL options are sorted by name. If this is
+ * not the case, the result returned by the _vsession_settings
+ * space iterator will not be sorted properly.
+ */
+enum {
+	SQL_OPTION_COMPOUND_SELECT_LIMIT = 0,
+	SQL_OPTION_DEFAULT_ENGINE,
+	SQL_OPTION_DEFER_FOREIGN_KEYS,
+	SQL_OPTION_FULL_COLUMN_NAMES,
+#ifndef NDEBUG
+	SQL_OPTION_PARSER_TRACE,
+#endif
+	SQL_OPTION_RECURSIVE_TRIGGERS,
+	SQL_OPTION_REVERSE_UNORDERED_SELECTS,
+#ifndef NDEBUG
+	SQL_OPTION_SELECT_TRACE,
+	SQL_OPTION_TRACE,
+	SQL_OPTION_VDBE_ADDOPTRACE,
+	SQL_OPTION_VDBE_DEBUG,
+	SQL_OPTION_VDBE_EQP,
+	SQL_OPTION_VDBE_LISTING,
+	SQL_OPTION_VDBE_TRACE,
+	SQL_OPTION_WHERE_TRACE,
+#endif
+	SQL_OPTION_max,
+};
+
+/**
+ * A local structure that allows to establish a connection between
+ * the name of the parameter, its field type and mask, if it have
+ * one.
+ */
+struct sql_option_metadata
+{
+	const char *name;
+	uint32_t field_type;
+	uint32_t mask;
+};
+
+/**
+ * Variable that contains names of the SQL options, their field
+ * types and mask if they have one or 0 if don't have.
+ *
+ * It is IMPORTANT that these options sorted by name.
+ */
+static struct sql_option_metadata sql_options[] = {
+	/** SQL_OPTION_COMPOUND_SELECT_LIMIT */
+	{"sql_compound_select_limit", FIELD_TYPE_INTEGER, 0},
+	/** SQL_OPTION_DEFAULT_ENGINE */
+	{"sql_default_engine", FIELD_TYPE_STRING, 0},
+	/** SQL_OPTION_DEFER_FOREIGN_KEYS */
+	{"sql_defer_foreign_keys", FIELD_TYPE_BOOLEAN, SQL_DeferFKs},
+	/** SQL_OPTION_FULL_COLUMN_NAMES */
+	{"sql_full_column_names", FIELD_TYPE_BOOLEAN, SQL_FullColNames},
+#ifndef NDEBUG
+	/** SQL_OPTION_PARSER_TRACE */
+	{"sql_parser_trace", FIELD_TYPE_BOOLEAN, PARSER_TRACE_FLAG},
+#endif
+	/** SQL_OPTION_RECURSIVE_TRIGGERS */
+	{"sql_recursive_triggers", FIELD_TYPE_BOOLEAN, SQL_RecTriggers},
+	/** SQL_OPTION_REVERSE_UNORDERED_SELECTS */
+	{"sql_reverse_unordered_selects", FIELD_TYPE_BOOLEAN, SQL_ReverseOrder},
+#ifndef NDEBUG
+	/** SQL_OPTION_SELECT_TRACE */
+	{"sql_select_trace", FIELD_TYPE_BOOLEAN, SQL_SelectTrace},
+	/** SQL_OPTION_TRACE */
+	{"sql_trace", FIELD_TYPE_BOOLEAN, SQL_SqlTrace},
+	/** SQL_OPTION_VDBE_ADDOPTRACE */
+	{"sql_vdbe_addoptrace", FIELD_TYPE_BOOLEAN, SQL_VdbeAddopTrace},
+	/** SQL_OPTION_VDBE_DEBUG */
+	{"sql_vdbe_debug", FIELD_TYPE_BOOLEAN,
+	 SQL_SqlTrace | SQL_VdbeListing | SQL_VdbeTrace},
+	/** SQL_OPTION_VDBE_EQP */
+	{"sql_vdbe_eqp", FIELD_TYPE_BOOLEAN, SQL_VdbeEQP},
+	/** SQL_OPTION_VDBE_LISTING */
+	{"sql_vdbe_listing", FIELD_TYPE_BOOLEAN, SQL_VdbeListing},
+	/** SQL_OPTION_VDBE_TRACE */
+	{"sql_vdbe_trace", FIELD_TYPE_BOOLEAN, SQL_VdbeTrace},
+	/** SQL_OPTION_WHERE_TRACE */
+	{"sql_where_trace", FIELD_TYPE_BOOLEAN, SQL_WhereTrace},
+#endif
+};
+
+uint32_t
+sql_option_id_max()
+{
+	return SQL_OPTION_max;
+}
+
+int
+sql_option_id_by_name(const char *name)
+{
+	for (uint32_t id = 0; id < SQL_OPTION_max; ++id) {
+		if (strcmp(name, sql_options[id].name) == 0)
+			return id;
+	}
+	return SQL_OPTION_max;
+}
+
+int
+sql_option_tuple(struct tuple_format *format, int option_id,
+		 struct tuple **result)
+{
+	if (option_id < 0 || option_id >= SQL_OPTION_max) {
+		*result = NULL;
+		return 0;
+	}
+	int limit = 0;
+	const char *engine = NULL;
+	struct region *region = &fiber()->gc;
+	struct session *session = current_session();
+	uint32_t flags = session->sql_flags;
+	uint32_t mask = sql_options[option_id].mask;
+	/* Tuple format contains two fields - name and value. */
+	uint32_t column_count = format->min_field_count;
+	assert(column_count == 2);
+	size_t size = mp_sizeof_array(column_count) +
+		      mp_sizeof_str(strlen(sql_options[option_id].name));
+	if (sql_options[option_id].field_type == FIELD_TYPE_BOOLEAN) {
+		size += mp_sizeof_bool(true);
+	} else if (option_id == SQL_OPTION_DEFAULT_ENGINE) {
+		engine = sql_storage_engine_strs[session->sql_default_engine];
+		size += mp_sizeof_str(strlen(engine));
+	} else {
+		assert(option_id == SQL_OPTION_COMPOUND_SELECT_LIMIT);
+		limit = sql_get()->aLimit[SQL_LIMIT_COMPOUND_SELECT];
+		size += mp_sizeof_uint(limit);
+	}
+
+	size_t svp = region_used(region);
+	char *pos_ret = region_alloc(region, size);
+	if (pos_ret == NULL) {
+		diag_set(OutOfMemory, size, "region_alloc", "pos_ret");
+		return -1;
+	}
+	char *pos = mp_encode_array(pos_ret, column_count);
+	pos = mp_encode_str(pos, sql_options[option_id].name,
+			    strlen(sql_options[option_id].name));
+	if (sql_options[option_id].field_type == FIELD_TYPE_BOOLEAN)
+		pos = mp_encode_bool(pos, (flags & mask) == mask);
+	else if (option_id == SQL_OPTION_DEFAULT_ENGINE)
+		pos = mp_encode_str(pos, engine, strlen(engine));
+	else
+		pos = mp_encode_uint(pos, limit);
+	struct tuple *tuple = tuple_new(format, pos_ret, pos_ret + size);
+	region_truncate(region, svp);
+	if (tuple == NULL)
+		return -1;
+	*result = tuple;
+	return 0;
+}
diff --git a/src/box/sysview.c b/src/box/sysview.c
index 745cf09..83a8ccc 100644
--- a/src/box/sysview.c
+++ b/src/box/sysview.c
@@ -411,7 +411,7 @@ vsequence_filter(struct space *source, struct tuple *tuple)
 }
 
 static bool
-vcollation_filter(struct space *source, struct tuple *tuple)
+generic_filter(struct space *source, struct tuple *tuple)
 {
 	(void) source;
 	(void) tuple;
@@ -481,10 +481,17 @@ sysview_space_create_index(struct space *space, struct index_def *def)
 	case BOX_VCOLLATION_ID:
 		source_space_id = BOX_COLLATION_ID;
 		source_index_id = def->iid;
-		filter = vcollation_filter;
+		filter = generic_filter;
 		get = index_get;
 		create_iterator = index_create_iterator;
 		break;
+	case BOX_VSESSION_SETTINGS_ID:
+		source_space_id = BOX_VSESSION_SETTINGS_ID;
+		source_index_id = def->iid;
+		filter = generic_filter;
+		get = session_options_get;
+		create_iterator = session_options_create_iterator;
+		break;
 	default:
 		diag_set(ClientError, ER_MODIFY_INDEX,
 			 def->name, space_name(space),
@@ -569,9 +576,10 @@ sysview_engine_create_space(struct engine *engine, struct space_def *def,
 		return NULL;
 	}
 	struct tuple_format *format =
-		tuple_format_new(NULL, NULL, keys, key_count, def->fields,
-				 def->field_count, def->exact_field_count,
-				 def->dict, def->opts.is_temporary,
+		tuple_format_new(&tuple_format_runtime->vtab, NULL, keys,
+				 key_count, def->fields, def->field_count,
+				 def->exact_field_count, def->dict,
+				 def->opts.is_temporary,
 				 def->opts.is_ephemeral);
 	if (format == NULL) {
 		free(space);
diff --git a/test/app-tap/tarantoolctl.test.lua b/test/app-tap/tarantoolctl.test.lua
index f388208..a41fad3 100755
--- a/test/app-tap/tarantoolctl.test.lua
+++ b/test/app-tap/tarantoolctl.test.lua
@@ -410,8 +410,8 @@ do
             check_ctlcat_xlog(test_i, dir, "--from=3 --to=6 --format=json --show-system --replica 1", "\n", 3)
             check_ctlcat_xlog(test_i, dir, "--from=3 --to=6 --format=json --show-system --replica 1 --replica 2", "\n", 3)
             check_ctlcat_xlog(test_i, dir, "--from=3 --to=6 --format=json --show-system --replica 2", "\n", 0)
-            check_ctlcat_snap(test_i, dir, "--space=280", "---\n", 24)
-            check_ctlcat_snap(test_i, dir, "--space=288", "---\n", 52)
+            check_ctlcat_snap(test_i, dir, "--space=280", "---\n", 25)
+            check_ctlcat_snap(test_i, dir, "--space=288", "---\n", 53)
         end)
     end)
 
diff --git a/test/box-py/bootstrap.result b/test/box-py/bootstrap.result
index 123aa2f..54b43ec 100644
--- a/test/box-py/bootstrap.result
+++ b/test/box-py/bootstrap.result
@@ -4,7 +4,7 @@ box.internal.bootstrap()
 box.space._schema:select{}
 ---
 - - ['max_id', 511]
-  - ['version', 2, 3, 0]
+  - ['version', 2, 3, 1]
 ...
 box.space._cluster:select{}
 ---
@@ -96,6 +96,8 @@ box.space._space:select{}
         'type': 'boolean'}]]
   - [372, 1, '_func_index', 'memtx', 0, {}, [{'name': 'space_id', 'type': 'unsigned'},
       {'name': 'index_id', 'type': 'unsigned'}, {'name': 'func_id', 'type': 'unsigned'}]]
+  - [381, 1, '_vsession_settings', 'sysview', 0, {}, [{'name': 'name', 'type': 'string'},
+      {'name': 'value', 'type': 'any'}]]
 ...
 box.space._index:select{}
 ---
@@ -153,6 +155,7 @@ box.space._index:select{}
   - [364, 0, 'primary', 'tree', {'unique': true}, [[0, 'unsigned'], [1, 'string']]]
   - [372, 0, 'primary', 'tree', {'unique': true}, [[0, 'unsigned'], [1, 'unsigned']]]
   - [372, 1, 'fid', 'tree', {'unique': false}, [[2, 'unsigned']]]
+  - [381, 0, 'primary', 'tree', {'unique': true}, [[0, 'string']]]
 ...
 box.space._user:select{}
 ---
diff --git a/test/box/access_sysview.result b/test/box/access_sysview.result
index 3072b73..5a41526 100644
--- a/test/box/access_sysview.result
+++ b/test/box/access_sysview.result
@@ -246,11 +246,11 @@ box.session.su('guest')
 ...
 #box.space._vspace:select{}
 ---
-- 25
+- 26
 ...
 #box.space._vindex:select{}
 ---
-- 53
+- 54
 ...
 #box.space._vuser:select{}
 ---
@@ -282,7 +282,7 @@ box.session.su('guest')
 ...
 #box.space._vindex:select{}
 ---
-- 53
+- 54
 ...
 #box.space._vuser:select{}
 ---
diff --git a/test/box/alter.result b/test/box/alter.result
index 46ce868..2a0eaca 100644
--- a/test/box/alter.result
+++ b/test/box/alter.result
@@ -92,7 +92,7 @@ space = box.space[t[1]]
 ...
 space.id
 ---
-- 373
+- 382
 ...
 space.field_count
 ---
@@ -137,7 +137,7 @@ space_deleted
 ...
 space:replace{0}
 ---
-- error: Space '373' does not exist
+- error: Space '382' does not exist
 ...
 _index:insert{_space.id, 0, 'primary', 'tree', {unique=true}, {{0, 'unsigned'}}}
 ---
@@ -220,6 +220,7 @@ _index:select{}
   - [364, 0, 'primary', 'tree', {'unique': true}, [[0, 'unsigned'], [1, 'string']]]
   - [372, 0, 'primary', 'tree', {'unique': true}, [[0, 'unsigned'], [1, 'unsigned']]]
   - [372, 1, 'fid', 'tree', {'unique': false}, [[2, 'unsigned']]]
+  - [381, 0, 'primary', 'tree', {'unique': true}, [[0, 'string']]]
 ...
 -- modify indexes of a system space
 _index:delete{_index.id, 0}
diff --git a/test/box/misc.result b/test/box/misc.result
index b293051..b41ffa4 100644
--- a/test/box/misc.result
+++ b/test/box/misc.result
@@ -1330,3 +1330,124 @@ test_run:grep_log('default', 'test log')
 ---
 - test log
 ...
+--
+-- gh-4511: make sure that _vsession_settings sysview works as
+-- intended.
+--
+v = box.space._vsession_settings
+---
+...
+option_count = v:count()
+---
+...
+v:format()
+---
+- [{'name': 'name', 'type': 'string'}, {'name': 'value', 'type': 'any'}]
+...
+(#v:select()) == option_count
+---
+- true
+...
+(#v:select({}, {iterator = 'ALL'})) == option_count
+---
+- true
+...
+(#v:select({}, {iterator = 'REQ'})) == option_count
+---
+- true
+...
+(#v:select({}, {iterator = 'EQ'})) == option_count
+---
+- true
+...
+(#v:select({}, {iterator = 'GE'})) == option_count
+---
+- true
+...
+(#v:select({}, {iterator = 'GT'})) == option_count
+---
+- true
+...
+(#v:select({}, {iterator = 'LE'})) == option_count
+---
+- true
+...
+(#v:select({}, {iterator = 'LT'})) == option_count
+---
+- true
+...
+(#v:select({'abcde'}, {iterator = 'ALL'})) == 0
+---
+- true
+...
+(#v:select({'abcde'}, {iterator = 'REQ'})) == 0
+---
+- true
+...
+(#v:select({'abcde'}, {iterator = 'EQ'})) == 0
+---
+- true
+...
+(#v:select({'abcde'}, {iterator = 'GE'})) == 0
+---
+- true
+...
+(#v:select({'abcde'}, {iterator = 'GT'})) == 0
+---
+- true
+...
+(#v:select({'abcde'}, {iterator = 'LE'})) == option_count
+---
+- true
+...
+(#v:select({'abcde'}, {iterator = 'LT'})) == option_count
+---
+- true
+...
+v:select({'sql_defer_foreign_keys'})
+---
+- - ['sql_defer_foreign_keys', false]
+...
+v:select({'sql_recursive_triggers'})
+---
+- - ['sql_recursive_triggers', true]
+...
+v:select({'sql_reverse_unordered_selects'})
+---
+- - ['sql_reverse_unordered_selects', false]
+...
+v:select({'sql_compound_select_limit'})
+---
+- - ['sql_compound_select_limit', 30]
+...
+v:select({'sql_default_engine'})
+---
+- - ['sql_default_engine', 'memtx']
+...
+new_record = v:frommap({name='abs', value=123})
+---
+...
+v:insert(new_record)
+---
+- error: View '_vsession_settings' is read-only
+...
+t = {}
+---
+...
+for k, v in box.space._vsession_settings:pairs() do table.insert(t, {k, v}) end
+---
+...
+#t == option_count
+---
+- true
+...
+box.execute([[SELECT * from "_vsession_settings" WHERE "name" = 'sql_default_engine']])
+---
+- metadata:
+  - name: name
+    type: string
+  - name: value
+    type: any
+  rows:
+  - ['sql_default_engine', 'memtx']
+...
diff --git a/test/box/misc.test.lua b/test/box/misc.test.lua
index cc223b2..50c89df 100644
--- a/test/box/misc.test.lua
+++ b/test/box/misc.test.lua
@@ -383,3 +383,45 @@ tuple_format = box.internal.new_tuple_format(format)
 box.cfg{}
 local ffi = require'ffi' ffi.C._say(ffi.C.S_WARN, nil, 0, nil, "%s", "test log")
 test_run:grep_log('default', 'test log')
+
+--
+-- gh-4511: make sure that _vsession_settings sysview works as
+-- intended.
+--
+
+v = box.space._vsession_settings
+option_count = v:count()
+
+v:format()
+
+(#v:select()) == option_count
+(#v:select({}, {iterator = 'ALL'})) == option_count
+(#v:select({}, {iterator = 'REQ'})) == option_count
+(#v:select({}, {iterator = 'EQ'})) == option_count
+(#v:select({}, {iterator = 'GE'})) == option_count
+(#v:select({}, {iterator = 'GT'})) == option_count
+(#v:select({}, {iterator = 'LE'})) == option_count
+(#v:select({}, {iterator = 'LT'})) == option_count
+
+(#v:select({'abcde'}, {iterator = 'ALL'})) == 0
+(#v:select({'abcde'}, {iterator = 'REQ'})) == 0
+(#v:select({'abcde'}, {iterator = 'EQ'})) == 0
+(#v:select({'abcde'}, {iterator = 'GE'})) == 0
+(#v:select({'abcde'}, {iterator = 'GT'})) == 0
+(#v:select({'abcde'}, {iterator = 'LE'})) == option_count
+(#v:select({'abcde'}, {iterator = 'LT'})) == option_count
+
+v:select({'sql_defer_foreign_keys'})
+v:select({'sql_recursive_triggers'})
+v:select({'sql_reverse_unordered_selects'})
+v:select({'sql_compound_select_limit'})
+v:select({'sql_default_engine'})
+
+new_record = v:frommap({name='abs', value=123})
+v:insert(new_record)
+
+t = {}
+for k, v in box.space._vsession_settings:pairs() do table.insert(t, {k, v}) end
+#t == option_count
+
+box.execute([[SELECT * from "_vsession_settings" WHERE "name" = 'sql_default_engine']])
diff --git a/test/wal_off/alter.result b/test/wal_off/alter.result
index 62cb11d..97f7e6f 100644
--- a/test/wal_off/alter.result
+++ b/test/wal_off/alter.result
@@ -28,7 +28,7 @@ end;
 ...
 #spaces;
 ---
-- 65502
+- 65501
 ...
 -- cleanup
 for k, v in pairs(spaces) do
-- 
2.7.4