Re: [Tarantool-patches] [PATCH] sql: support column addition

[Roman Khabibov <roman.habibov@tarantool.org>]

Vlad, can you take it, please?

> On Jan 31, 2020, at 18:05, Roman Khabibov <roman.habibov@tarantool.org> wrote:
> 
> Enable to add column to existing space with
> <ALTER TABLE ADD [COLUMN]> statement. Column definition can be
> supplemented with <DEFAULT>, <COLLATE> clauses and <[NOT] NULL>
> column constraint.
> 
> Closes #3075
> 
> @TarantoolBot document
> Title: Add columns to existing tables in SQL
> Now, it is possible to add columns to existing empty spaces using
> <ALTER TABLE table_name ADD [COLUMN] column_name column_type ...>
> statement. The column definition is the same as in <CREATE TABLE>
> statement, except that table constraints (PRIMARY KEY, UNIQUE,
> REFERENCES, CHECK) cannot be specified yet.
> 
> For example:
> 
> tarantool> box.execute([[CREATE TABLE test (
>                            a INTEGER PRIMARY KEY
>                       );]])
> ---
> - row_count: 1
> ...
> 
> tarantool> box.execute([[ALTER TABLE test ADD COLUMN
>                            b TEXT
>                            NOT NULL
>                            DEFAULT ('a')
>                            COLLATE "unicode_ci"
>                        ;]])
> ---
> - row_count: 0
> ...
> ---
> Branch: https://github.com/tarantool/tarantool/tree/romanhabibov/gh-3075-add-column
> Issue: https://github.com/tarantool/tarantool/issues/3075
> 
> P.S.: I didn't implement column constraints in ADD COLUMN statement,
> because of the sql_create_index(), sql_create_foreign_key() and
> sql_create_check_contraint() functions. These functions have
> branching inside:
> 
> 1) CREATE TABLE (parse->create_table_def.new_space != NULL)
> We work with the ephemeral space. Use its def, indexes array,
> ck and fk rlists for checks, opcode emitting, etc and modify it on
> parsing level.
> 
> 2) ALTER TABLE (parse->create_table_def.new_space == NULL)
> We work with existing space = space_by_name(), but don't modify it.
> This space will be modified after parsing by alter.cc triggers.
> 
> In the case of
> ALTER TABLE test ADD a INT PRIMARY KEY CONSTRAINT c UNIQUE CONSTRAINT d UNIQUE ...
> we need to modifiy the existing space, for example UNIQUE constraint
> creation/opcode emitting requires new space def with new modified
> fields array and new index_id_max. The same is for REFERENCES
> constraint. With CHECK it seems easier, but I didn't implement it,
> because I want to do patch in the futue: "Enable constraints in ADD COLUMN",
> if it will be needed.
> 
> There is obvious way to implement constraints parsing during
> ADD COLUMN. To do partial copy of space = space_by_name() on region,
> to keep it in parse->create_column_>def and to work with it. Then
> we will have to change the current code a bit, but it is necessary
> to write API to create an ephemeral space based on the existing.
> 
> I would like to hear your opinion. Maybe I'm generally wrong in
> thinking about all this, and it could be made easier.
> 
> P.P.S.: Could you, please, help me with COLUMN keyword support.
> I couldn't add it as I wanted, i.e., the line in parse.y near the
> line 1754:
> column_name(N) ::= COLUMN nm(A). { N = A; }
> because I had:
> /Users/r.khabibov/tarantool/src/box/sql/parse.h:171:9: error: 'TK_COLUMN' macro redefined
> #define TK_COLUMN
> 
> I don't understand why it is so? For example, the definition of
> CONSTRAINT keyword in mkkeywordhash.c is the same, but there is no
> error about this #define during compilation.
> 
>  { "COLUMN",                 "TK_COLUMN",      true  },
>  { "CONSTRAINT",             "TK_CONSTRAINT",  true  },
> 
> extra/mkkeywordhash.c       |   6 +-
> src/box/errcode.h           |   1 +
> src/box/sql.c               |  28 +++++---
> src/box/sql/alter.c         | 125 ++++++++++++++++++++++++++++++++++++
> src/box/sql/build.c         | 106 ++++++++++++++++++------------
> src/box/sql/parse.y         |  59 +++++++++++++++--
> src/box/sql/parse_def.h     |  23 +++++++
> src/box/sql/sqlInt.h        |  40 ++++++++++++
> src/box/sql/tarantoolInt.h  |   6 +-
> test/box/misc.result        |   1 +
> test/sql-tap/alter.test.lua |  76 +++++++++++++++++++++-
> 11 files changed, 405 insertions(+), 66 deletions(-)
> 
> diff --git a/extra/mkkeywordhash.c b/extra/mkkeywordhash.c
> index 006285622..51c8cbb18 100644
> --- a/extra/mkkeywordhash.c
> +++ b/extra/mkkeywordhash.c
> @@ -75,11 +75,7 @@ static Keyword aKeywordTable[] = {
>   { "CAST",                   "TK_CAST",        false },
>   { "CHECK",                  "TK_CHECK",       true  },
>   { "COLLATE",                "TK_COLLATE",     true  },
> -  /* gh-3075: Reserved until ALTER ADD COLUMN is implemeneted.
> -   * Move it back to ALTER when done.
> -   */
> -  /* { "COLUMN",              "TK_COLUMNKW",    true  }, */
> -  { "COLUMN",                 "TK_STANDARD",    true  },
> +  { "COLUMN",                 "TK_COLUMN",      true  },
>   { "COMMIT",                 "TK_COMMIT",      true  },
>   { "CONFLICT",               "TK_CONFLICT",    false },
>   { "CONSTRAINT",             "TK_CONSTRAINT",  true  },
> diff --git a/src/box/errcode.h b/src/box/errcode.h
> index 3065b1948..e076edf02 100644
> --- a/src/box/errcode.h
> +++ b/src/box/errcode.h
> @@ -264,6 +264,7 @@ struct errcode_record {
> 	/*209 */_(ER_SESSION_SETTING_INVALID_VALUE,	"Session setting %s expected a value of type %s") \
> 	/*210 */_(ER_SQL_PREPARE,		"Failed to prepare SQL statement: %s") \
> 	/*211 */_(ER_WRONG_QUERY_ID,		"Prepared statement with id %u does not exist") \
> +	/*212 */_(ER_SQL_CANT_ADD_COLUMN_TO_VIEW,	"Can't add column '%s' to the view '%s'") \
> 
> /*
>  * !IMPORTANT! Please follow instructions at start of the file
> diff --git a/src/box/sql.c b/src/box/sql.c
> index 1256df856..7157cabe6 100644
> --- a/src/box/sql.c
> +++ b/src/box/sql.c
> @@ -923,7 +923,8 @@ cursor_advance(BtCursor *pCur, int *pRes)
>  */
> 
> char *
> -sql_encode_table(struct region *region, struct space_def *def, uint32_t *size)
> +sql_encode_table_format(struct region *region, struct field_def *fields,
> +			uint32_t field_count, uint32_t *size)
> {
> 	size_t used = region_used(region);
> 	struct mpstream stream;
> @@ -931,12 +932,11 @@ sql_encode_table(struct region *region, struct space_def *def, uint32_t *size)
> 	mpstream_init(&stream, region, region_reserve_cb, region_alloc_cb,
> 		      set_encode_error, &is_error);
> 
> -	assert(def != NULL);
> -	uint32_t field_count = def->field_count;
> +	assert(fields != NULL);
> 	mpstream_encode_array(&stream, field_count);
> 	for (uint32_t i = 0; i < field_count && !is_error; i++) {
> -		uint32_t cid = def->fields[i].coll_id;
> -		struct field_def *field = &def->fields[i];
> +		struct field_def *field = &fields[i];
> +		uint32_t cid = field->coll_id;
> 		const char *default_str = field->default_value;
> 		int base_len = 4;
> 		if (cid != COLL_NONE)
> @@ -947,16 +947,16 @@ sql_encode_table(struct region *region, struct space_def *def, uint32_t *size)
> 		mpstream_encode_str(&stream, "name");
> 		mpstream_encode_str(&stream, field->name);
> 		mpstream_encode_str(&stream, "type");
> -		assert(def->fields[i].is_nullable ==
> -		       action_is_nullable(def->fields[i].nullable_action));
> +		assert(field->is_nullable ==
> +		       action_is_nullable(field->nullable_action));
> 		mpstream_encode_str(&stream, field_type_strs[field->type]);
> 		mpstream_encode_str(&stream, "is_nullable");
> -		mpstream_encode_bool(&stream, def->fields[i].is_nullable);
> +		mpstream_encode_bool(&stream, field->is_nullable);
> 		mpstream_encode_str(&stream, "nullable_action");
> 
> -		assert(def->fields[i].nullable_action < on_conflict_action_MAX);
> +		assert(field->nullable_action < on_conflict_action_MAX);
> 		const char *action =
> -			on_conflict_action_strs[def->fields[i].nullable_action];
> +			on_conflict_action_strs[field->nullable_action];
> 		mpstream_encode_str(&stream, action);
> 		if (cid != COLL_NONE) {
> 			mpstream_encode_str(&stream, "collation");
> @@ -980,6 +980,14 @@ sql_encode_table(struct region *region, struct space_def *def, uint32_t *size)
> 	return raw;
> }
> 
> +char *
> +sql_encode_table(struct region *region, struct space_def *def, uint32_t *size)
> +{
> +	assert(def != NULL);
> +	return sql_encode_table_format(region, def->fields, def->field_count,
> +				       size);
> +}
> +
> char *
> sql_encode_table_opts(struct region *region, struct space_def *def,
> 		      uint32_t *size)
> diff --git a/src/box/sql/alter.c b/src/box/sql/alter.c
> index 973b420cf..c12d9373a 100644
> --- a/src/box/sql/alter.c
> +++ b/src/box/sql/alter.c
> @@ -36,6 +36,7 @@
> #include "sqlInt.h"
> #include "box/box.h"
> #include "box/schema.h"
> +#include "tarantoolInt.h"
> 
> void
> sql_alter_table_rename(struct Parse *parse)
> @@ -209,3 +210,127 @@ rename_trigger(sql *db, char const *sql_stmt, char const *table_name,
> 				      table_name, tname.z + tname.n);
> 	return new_sql_stmt;
> }
> +
> +void
> +sql_alter_add_column_start(struct Parse *parse)
> +{
> +	struct create_column_def *create_column_def = &parse->create_column_def;
> +	struct alter_entity_def *alter_entity_def =
> +		&create_column_def->base.base;
> +	assert(alter_entity_def->entity_type == ENTITY_TYPE_COLUMN);
> +	assert(alter_entity_def->alter_action == ALTER_ACTION_CREATE);
> +
> +	const char *space_name =
> +		alter_entity_def->entity_name->a[0].zName;
> +	struct space *space = space_by_name(space_name);
> +	struct sql *db = parse->db;
> +	if (space == NULL) {
> +		diag_set(ClientError, ER_NO_SUCH_SPACE, space_name);
> +		goto tnt_error;
> +	}
> +
> +	struct space_def *def = space->def;
> +	create_column_def->space_def = def;
> +	if (sql_space_def_check_format(def) != 0)
> +		goto tnt_error;
> +	uint32_t new_field_count = def->field_count + 1;
> +	create_column_def->new_field_count = new_field_count;
> +
> +#if SQL_MAX_COLUMN
> +	if ((int)new_field_count > db->aLimit[SQL_LIMIT_COLUMN]) {
> +		diag_set(ClientError, ER_SQL_COLUMN_COUNT_MAX, def->name,
> +			 new_field_count, db->aLimit[SQL_LIMIT_COLUMN]);
> +		goto tnt_error;
> +	}
> +#endif
> +	/*
> +	 * Create new fields array and add the new column's
> +	 * field_def to its end. During copying don't make
> +	 * duplicates of the non-scalar fields (name,
> +	 * default_value, default_value_expr), because they will
> +	 * be just copied and encoded to the msgpack array on sql
> +	 * allocator in sql_alter_add_column_end().
> +	 */
> +	uint32_t size = sizeof(struct field_def) * new_field_count;
> +	struct region *region = &parse->region;
> +	struct field_def *new_fields = region_alloc(region, size);
> +	if (new_fields == NULL) {
> +		diag_set(OutOfMemory, size, "region_alloc", "new_fields");
> +		goto tnt_error;
> +	}
> +	memcpy(new_fields, def->fields,
> +	       sizeof(struct field_def) * def->field_count);
> +	create_column_def->new_fields = new_fields;
> +	struct field_def *new_column_def = &new_fields[def->field_count];
> +
> +	memcpy(new_column_def, &field_def_default, sizeof(struct field_def));
> +	struct Token *name = &create_column_def->base.name;
> +	new_column_def->name =
> +		sql_normalized_name_region_new(region, name->z, name->n);
> +	if (new_column_def->name == NULL)
> +		goto tnt_error;
> +	if (def->opts.is_view) {
> +		diag_set(ClientError, ER_SQL_CANT_ADD_COLUMN_TO_VIEW,
> +			 new_column_def->name, def->name);
> +		goto tnt_error;
> +	}
> +
> +	new_column_def->type = create_column_def->type_def->type;
> +
> +exit_alter_add_column_start:
> +	sqlSrcListDelete(db, alter_entity_def->entity_name);
> +	return;
> +tnt_error:
> +	parse->is_aborted = true;
> +	goto exit_alter_add_column_start;
> +}
> +
> +void
> +sql_alter_add_column_end(struct Parse *parse)
> +{
> +	struct create_column_def *create_column_def = &parse->create_column_def;
> +	uint32_t new_field_count = create_column_def->new_field_count;
> +	uint32_t table_stmt_sz = 0;
> +	char *table_stmt =
> +		sql_encode_table_format(&parse->region,
> +					create_column_def->new_fields,
> +					new_field_count, &table_stmt_sz);
> +	if (table_stmt == NULL) {
> +		parse->is_aborted = true;
> +		return;
> +	}
> +	char *raw = sqlDbMallocRaw(parse->db, table_stmt_sz);
> +	if (raw == NULL){
> +		parse->is_aborted = true;
> +		return;
> +	}
> +	memcpy(raw, table_stmt, table_stmt_sz);
> +
> +	struct space *system_space = space_by_id(BOX_SPACE_ID);
> +	assert(system_space != NULL);
> +	int cursor = parse->nTab++;
> +	struct Vdbe *v = sqlGetVdbe(parse);
> +	assert(v != NULL);
> +	vdbe_emit_open_cursor(parse, cursor, 0, system_space);
> +	sqlVdbeChangeP5(v, OPFLAG_SYSTEMSP);
> +
> +	int key_reg = sqlGetTempReg(parse);
> +	sqlVdbeAddOp2(v, OP_Integer, create_column_def->space_def->id, key_reg);
> +	int addr = sqlVdbeAddOp4Int(v, OP_Found, cursor, 0, key_reg, 1);
> +	sqlVdbeAddOp2(v, OP_Halt, -1, ON_CONFLICT_ACTION_ABORT);
> +	sqlVdbeJumpHere(v, addr);
> +
> +	const int system_space_field_count = 7;
> +	int tuple_reg = sqlGetTempRange(parse, system_space_field_count + 1);
> +	for (int i = 0; i < system_space_field_count - 1; ++i)
> +		sqlVdbeAddOp3(v, OP_Column, cursor, i, tuple_reg + i);
> +	sqlVdbeAddOp1(v, OP_Close, cursor);
> +
> +	sqlVdbeAddOp2(v, OP_Integer, new_field_count, tuple_reg + 4);
> +	sqlVdbeAddOp4(v, OP_Blob, table_stmt_sz, tuple_reg + 6,
> +		      SQL_SUBTYPE_MSGPACK, raw, P4_DYNAMIC);
> +	sqlVdbeAddOp3(v, OP_MakeRecord, tuple_reg, system_space_field_count,
> +		      tuple_reg + system_space_field_count);
> +	sqlVdbeAddOp4(v, OP_IdxReplace, tuple_reg + system_space_field_count, 0,
> +		      0, (char *)system_space, P4_SPACEPTR);
> +}
> diff --git a/src/box/sql/build.c b/src/box/sql/build.c
> index bc50ecbfa..2f51b55df 100644
> --- a/src/box/sql/build.c
> +++ b/src/box/sql/build.c
> @@ -368,11 +368,21 @@ void
> sql_column_add_nullable_action(struct Parse *parser,
> 			       enum on_conflict_action nullable_action)
> {
> -	struct space *space = parser->create_table_def.new_space;
> -	if (space == NULL || NEVER(space->def->field_count < 1))
> +	struct space_def *def = NULL;
> +	struct field_def *field = NULL;
> +	if (parser->create_table_def.new_space != NULL) {
> +		def = parser->create_table_def.new_space->def;
> +		if (NEVER(def->field_count < 1))
> +			return;
> +		field = &def->fields[def->field_count - 1];
> +	} else if (parser->create_column_def.space_def != NULL) {
> +		def = parser->create_column_def.space_def;
> +		uint32_t field_count =
> +			parser->create_column_def.new_field_count;
> +		field = &parser->create_column_def.new_fields[field_count - 1];
> +	} else {
> 		return;
> -	struct space_def *def = space->def;
> -	struct field_def *field = &def->fields[def->field_count - 1];
> +	}
> 	if (field->nullable_action != ON_CONFLICT_ACTION_DEFAULT &&
> 	    nullable_action != field->nullable_action) {
> 		/* Prevent defining nullable_action many times. */
> @@ -390,51 +400,53 @@ sql_column_add_nullable_action(struct Parse *parser,
> }
> 
> /*
> - * The expression is the default value for the most recently added column
> - * of the table currently under construction.
> + * The expression is the default value for the most recently added
> + * column.
>  *
>  * Default value expressions must be constant.  Raise an exception if this
>  * is not the case.
>  *
>  * This routine is called by the parser while in the middle of
> - * parsing a CREATE TABLE statement.
> + * parsing a <CREATE TABLE> or <ALTER TABLE ADD COLUMN> statement.
>  */
> void
> sqlAddDefaultValue(Parse * pParse, ExprSpan * pSpan)
> {
> 	sql *db = pParse->db;
> -	struct space *p = pParse->create_table_def.new_space;
> -	if (p != NULL) {
> -		assert(p->def->opts.is_ephemeral);
> -		struct space_def *def = p->def;
> -		if (!sqlExprIsConstantOrFunction
> -		    (pSpan->pExpr, db->init.busy)) {
> -			const char *column_name =
> -				def->fields[def->field_count - 1].name;
> -			diag_set(ClientError, ER_CREATE_SPACE, def->name,
> -				 tt_sprintf("default value of column '%s' is "\
> -					    "not constant", column_name));
> +	struct space_def *def = NULL;
> +	struct field_def *field = NULL;
> +	if (pParse->create_table_def.new_space != NULL) {
> +		def = pParse->create_table_def.new_space->def;
> +		assert(def->opts.is_ephemeral);
> +		field = &def->fields[def->field_count - 1];
> +	} else if (pParse->create_column_def.space_def != NULL) {
> +		def = pParse->create_column_def.space_def;
> +		uint32_t field_count =
> +			pParse->create_column_def.new_field_count;
> +		field = &pParse->create_column_def.new_fields[field_count - 1];
> +	} else {
> +		goto add_default_value_exit;
> +	}
> +	if (!sqlExprIsConstantOrFunction(pSpan->pExpr, db->init.busy)) {
> +		diag_set(ClientError, ER_CREATE_SPACE, def->name,
> +			 tt_sprintf("default value of column '%s' is not "
> +				    "constant", field->name));
> +		pParse->is_aborted = true;
> +	} else {
> +		assert(def != NULL);
> +		struct region *region = &pParse->region;
> +		uint32_t default_length = (int)(pSpan->zEnd - pSpan->zStart);
> +		field->default_value = region_alloc(region, default_length + 1);
> +		if (field->default_value == NULL) {
> +			diag_set(OutOfMemory, default_length + 1,
> +				 "region_alloc", "field->default_value");
> 			pParse->is_aborted = true;
> -		} else {
> -			assert(def != NULL);
> -			struct field_def *field =
> -				&def->fields[def->field_count - 1];
> -			struct region *region = &pParse->region;
> -			uint32_t default_length = (int)(pSpan->zEnd - pSpan->zStart);
> -			field->default_value = region_alloc(region,
> -							    default_length + 1);
> -			if (field->default_value == NULL) {
> -				diag_set(OutOfMemory, default_length + 1,
> -					 "region_alloc",
> -					 "field->default_value");
> -				pParse->is_aborted = true;
> -				return;
> -			}
> -			strncpy(field->default_value, pSpan->zStart,
> -				default_length);
> -			field->default_value[default_length] = '\0';
> +			return;
> 		}
> +		strncpy(field->default_value, pSpan->zStart, default_length);
> +		field->default_value[default_length] = '\0';
> 	}
> +add_default_value_exit:
> 	sql_expr_delete(db, pSpan->pExpr, false);
> }
> 
> @@ -686,17 +698,27 @@ void
> sqlAddCollateType(Parse * pParse, Token * pToken)
> {
> 	struct space *space = pParse->create_table_def.new_space;
> -	if (space == NULL)
> +	uint32_t *coll_id = NULL;
> +	if (space != NULL) {
> +		uint32_t i = space->def->field_count - 1;
> +		coll_id = &space->def->fields[i].coll_id;
> +	} else if (pParse->create_column_def.space_def != NULL) {
> +		uint32_t field_count =
> +			pParse->create_column_def.new_field_count;
> +		struct field_def *field =
> +			&pParse->create_column_def.new_fields[field_count - 1];
> +		coll_id = &field->coll_id;
> +	} else {
> 		return;
> -	uint32_t i = space->def->field_count - 1;
> +	}
> 	sql *db = pParse->db;
> 	char *coll_name = sql_name_from_token(db, pToken);
> 	if (coll_name == NULL) {
> 		pParse->is_aborted = true;
> 		return;
> 	}
> -	uint32_t *coll_id = &space->def->fields[i].coll_id;
> -	if (sql_get_coll_seq(pParse, coll_name, coll_id) != NULL) {
> +	if (sql_get_coll_seq(pParse, coll_name, coll_id) != NULL &&
> +	    space != NULL) {
> 		/* If the column is declared as "<name> PRIMARY KEY COLLATE <type>",
> 		 * then an index may have been created on this column before the
> 		 * collation type was added. Correct this if it is the case.
> @@ -858,7 +880,9 @@ vdbe_emit_space_create(struct Parse *pParse, int space_id_reg,
> 	if (table_opts_stmt == NULL)
> 		goto error;
> 	uint32_t table_stmt_sz = 0;
> -	char *table_stmt = sql_encode_table(region, space->def, &table_stmt_sz);
> +	char *table_stmt = sql_encode_table_format(region, space->def->fields,
> +						   space->def->field_count,
> +						   &table_stmt_sz);
> 	if (table_stmt == NULL)
> 		goto error;
> 	char *raw = sqlDbMallocRaw(pParse->db,
> diff --git a/src/box/sql/parse.y b/src/box/sql/parse.y
> index cfe1c0012..2eba72ac3 100644
> --- a/src/box/sql/parse.y
> +++ b/src/box/sql/parse.y
> @@ -289,10 +289,14 @@ carglist ::= .
> %type cconsname { struct Token }
> cconsname(N) ::= CONSTRAINT nm(X). { N = X; }
> cconsname(N) ::= . { N = Token_nil; }
> -ccons ::= DEFAULT term(X).            {sqlAddDefaultValue(pParse,&X);}
> -ccons ::= DEFAULT LP expr(X) RP.      {sqlAddDefaultValue(pParse,&X);}
> -ccons ::= DEFAULT PLUS term(X).       {sqlAddDefaultValue(pParse,&X);}
> -ccons ::= DEFAULT MINUS(A) term(X).      {
> +ccons ::= default_clause_1.
> +default_clause_1 ::= DEFAULT term(X).           {sqlAddDefaultValue(pParse,&X);}
> +ccons ::= default_clause_2.
> +default_clause_2 ::= DEFAULT LP expr(X) RP.     {sqlAddDefaultValue(pParse,&X);}
> +ccons ::= default_clause_3.
> +default_clause_3 ::= DEFAULT PLUS term(X).      {sqlAddDefaultValue(pParse,&X);}
> +ccons ::= default_clause_4.
> +default_clause_4 ::= DEFAULT MINUS(A) term(X).      {
>   ExprSpan v;
>   v.pExpr = sqlPExpr(pParse, TK_UMINUS, X.pExpr, 0);
>   v.zStart = A.z;
> @@ -303,13 +307,18 @@ ccons ::= DEFAULT MINUS(A) term(X).      {
> // In addition to the type name, we also care about the primary key and
> // UNIQUE constraints.
> //
> -ccons ::= NULL onconf(R).        {
> +ccons ::= null_cons.
> +null_cons ::= NULL onconf(R).        {
>     sql_column_add_nullable_action(pParse, ON_CONFLICT_ACTION_NONE);
>     /* Trigger nullability mismatch error if required. */
>     if (R != ON_CONFLICT_ACTION_ABORT)
>         sql_column_add_nullable_action(pParse, R);
> }
> -ccons ::= NOT NULL onconf(R).    {sql_column_add_nullable_action(pParse, R);}
> +ccons ::= not_null_cons.
> +not_null_cons ::= NOT NULL onconf(R). {
> +  sql_column_add_nullable_action(pParse, R);
> +}
> +
> ccons ::= cconsname(N) PRIMARY KEY sortorder(Z). {
>   create_index_def_init(&pParse->create_index_def, NULL, &N, NULL,
>                         SQL_INDEX_TYPE_CONSTRAINT_PK, Z, false);
> @@ -335,7 +344,8 @@ ccons ::= cconsname(N) REFERENCES nm(T) eidlist_opt(TA) matcharg(M) refargs(R).
>   sql_create_foreign_key(pParse);
> }
> ccons ::= defer_subclause(D).    {fk_constraint_change_defer_mode(pParse, D);}
> -ccons ::= COLLATE id(C).        {sqlAddCollateType(pParse, &C);}
> +ccons ::= collate_clause.
> +collate_clause ::= COLLATE id(C).        {sqlAddCollateType(pParse, &C);}
> 
> // The optional AUTOINCREMENT keyword
> %type autoinc {int}
> @@ -1729,11 +1739,46 @@ alter_table_start(A) ::= ALTER TABLE fullname(T) . { A = T; }
> 
> %type alter_add_constraint {struct alter_args}
> alter_add_constraint(A) ::= alter_table_start(T) ADD CONSTRAINT nm(N). {
> +   A.table_name = T;
> +   A.name = N;
> +   pParse->initiateTTrans = true;
> + }
> +
> +%type alter_add_column {struct alter_args}
> +alter_add_column(A) ::= alter_table_start(T) ADD column_name(N). {
>   A.table_name = T;
>   A.name = N;
>   pParse->initiateTTrans = true;
> }
> 
> +column_name(N) ::= nm(A). { N = A; }
> +
> +cmd ::= alter_column_def alter_carglist add_column_end.
> +
> +alter_column_def ::= alter_add_column(N) typedef(Y). {
> +  create_column_def_init(&pParse->create_column_def, N.table_name, &N.name, &Y);
> +  sql_alter_add_column_start(pParse);
> +}
> +
> +/*
> + * "alter_carglist" is a list of additional constraints and
> + * clauses that come after the column name and column type in a
> + * ALTER TABLE ADD [COLUMN] statement.
> + */
> +alter_carglist ::= alter_carglist alter_ccons.
> +alter_carglist ::= .
> +alter_ccons ::= default_clause_1.
> +alter_ccons ::= default_clause_2.
> +alter_ccons ::= default_clause_3.
> +alter_ccons ::= default_clause_4.
> +alter_ccons ::= null_cons.
> +alter_ccons ::= not_null_cons.
> +alter_ccons ::= collate_clause.
> +
> +add_column_end ::= . {
> +  sql_alter_add_column_end(pParse);
> +}
> +
> cmd ::= alter_add_constraint(N) FOREIGN KEY LP eidlist(FA) RP REFERENCES
>         nm(T) eidlist_opt(TA) matcharg(M) refargs(R) defer_subclause_opt(D). {
>   create_fk_def_init(&pParse->create_fk_def, N.table_name, &N.name, FA, &T, TA,
> diff --git a/src/box/sql/parse_def.h b/src/box/sql/parse_def.h
> index 2f433e4c0..56887efa7 100644
> --- a/src/box/sql/parse_def.h
> +++ b/src/box/sql/parse_def.h
> @@ -154,6 +154,7 @@ enum sql_index_type {
> 
> enum entity_type {
> 	ENTITY_TYPE_TABLE = 0,
> +	ENTITY_TYPE_COLUMN,
> 	ENTITY_TYPE_VIEW,
> 	ENTITY_TYPE_INDEX,
> 	ENTITY_TYPE_TRIGGER,
> @@ -227,6 +228,18 @@ struct create_table_def {
> 	uint32_t autoinc_fieldno;
> };
> 
> +struct create_column_def {
> +	struct create_entity_def base;
> +	/** Column type. */
> +	struct type_def *type_def;
> +	/** Already existing space def. */
> +	struct space_def *space_def;
> +	/** New format array with the new column. */
> +	struct field_def *new_fields;
> +	/** Old field count + 1. */
> +	uint32_t new_field_count;
> +};
> +
> struct create_view_def {
> 	struct create_entity_def base;
> 	/**
> @@ -486,6 +499,16 @@ create_table_def_init(struct create_table_def *table_def, struct Token *name,
> 	table_def->autoinc_fieldno = 0;
> }
> 
> +static inline void
> +create_column_def_init(struct create_column_def *column_def,
> +		       struct SrcList *table_name, struct Token *name,
> +		       struct type_def *type_def)
> +{
> +	create_entity_def_init(&column_def->base, ENTITY_TYPE_COLUMN,
> +			       table_name, name, false);
> +	column_def->type_def = type_def;
> +}
> +
> static inline void
> create_view_def_init(struct create_view_def *view_def, struct Token *name,
> 		     struct Token *create, struct ExprList *aliases,
> diff --git a/src/box/sql/sqlInt.h b/src/box/sql/sqlInt.h
> index d1fcf4761..46d3d6d2a 100644
> --- a/src/box/sql/sqlInt.h
> +++ b/src/box/sql/sqlInt.h
> @@ -2231,6 +2231,7 @@ struct Parse {
> 	 * from parse.y
> 	 */
> 	union {
> +		struct create_column_def create_column_def;
> 		struct create_ck_def create_ck_def;
> 		struct create_fk_def create_fk_def;
> 		struct create_index_def create_index_def;
> @@ -2842,6 +2843,18 @@ struct space *
> sqlStartTable(Parse *, Token *);
> void sqlAddColumn(Parse *, Token *, struct type_def *);
> 
> +/**
> + * Set the is_nullable flag on the column @a field.
> + *
> + * @param field           Column to set.
> + * @param nullable_action on_conflict_action value.
> + * @param space_name Name of the space to which the column
> + *                   belongs. Needed to set error.
> + *
> + * @retval 0  Success.
> + * @retval -1 nullable_action has been already set.
> + */
> +
> /**
>  * This routine is called by the parser while in the middle of
>  * parsing a CREATE TABLE statement.  A "NOT NULL" constraint has
> @@ -2868,6 +2881,19 @@ sqlAddPrimaryKey(struct Parse *parse);
> void
> sql_create_check_contraint(Parse *parser);
> 
> +/**
> + * Add default value to the column @a field.
> + *
> + * @param parse      Parsing context.
> + * @param field      Column to set.
> + * @param span       Default expression.
> + * @param space_name Name of the space to which the column
> + *                   belongs. Needed to set error.
> + *
> + * @retval 0  Success.
> + * @retval -1 Error.
> + */
> +
> void sqlAddDefaultValue(Parse *, ExprSpan *);
> void sqlAddCollateType(Parse *, Token *);
> 
> @@ -4031,6 +4057,20 @@ sql_alter_table_rename(struct Parse *parse);
> void
> sql_alter_ck_constraint_enable(struct Parse *parse);
> 
> +/**
> + * Process the statement: do the checks of space and column
> + * definition. Create new format array with a new column.
> + */
> +void
> +sql_alter_add_column_start(struct Parse *parse);
> +
> +/**
> + * Encode new format array and emit code to update an entry in
> + * _space.
> + */
> +void
> +sql_alter_add_column_end(struct Parse *parse);
> +
> /**
>  * Return the length (in bytes) of the token that begins at z[0].
>  * Store the token type in *type before returning.
> diff --git a/src/box/sql/tarantoolInt.h b/src/box/sql/tarantoolInt.h
> index 1ded6c709..5fd433c60 100644
> --- a/src/box/sql/tarantoolInt.h
> +++ b/src/box/sql/tarantoolInt.h
> @@ -118,14 +118,16 @@ tarantoolsqlIncrementMaxid(uint64_t *space_max_id);
> /**
>  * Encode format as entry to be inserted to _space on @region.
>  * @param region Region to use.
> - * @param def Space definition to encode.
> + * @param fields Space format.
> + * @param field_count Number of fields.
>  * @param[out] size Size of result allocation.
>  *
>  * @retval NULL Error.
>  * @retval not NULL Pointer to msgpack on success.
>  */
> char *
> -sql_encode_table(struct region *region, struct space_def *def, uint32_t *size);
> +sql_encode_table_format(struct region *region, struct field_def *fields,
> +			uint32_t field_count, uint32_t *size);
> 
> /**
>  * Encode "opts" dictionary for _space entry on @region.
> diff --git a/test/box/misc.result b/test/box/misc.result
> index 3ca4e31ac..2aaec6566 100644
> --- a/test/box/misc.result
> +++ b/test/box/misc.result
> @@ -563,6 +563,7 @@ t;
>   209: box.error.SESSION_SETTING_INVALID_VALUE
>   210: box.error.SQL_PREPARE
>   211: box.error.WRONG_QUERY_ID
> +  212: box.error.SQL_CANT_ADD_COLUMN_TO_VIEW
> ...
> test_run:cmd("setopt delimiter ''");
> ---
> diff --git a/test/sql-tap/alter.test.lua b/test/sql-tap/alter.test.lua
> index 615b9d8a6..283dc1759 100755
> --- a/test/sql-tap/alter.test.lua
> +++ b/test/sql-tap/alter.test.lua
> @@ -1,6 +1,6 @@
> #!/usr/bin/env tarantool
> test = require("sqltester")
> -test:plan(50)
> +test:plan(57)
> 
> test:do_execsql_test(
>     "alter-1.1",
> @@ -585,4 +585,78 @@ test:do_catchsql_test(
> --         -- </alter-7.11>
> --     })
> 
> +--
> +-- gh-3075: Check <ALTER TABLE table ADD COLUMN column> statement.
> +--
> +test:do_execsql_test(
> +    "alter-9.1",
> +    [[
> +        CREATE TABLE test (a INTEGER PRIMARY KEY);
> +        ALTER TABLE test ADD b INTEGER;
> +    ]], {
> +        -- <alter-9.1>
> +        -- </alter-9.1>
> +    })
> +
> +test:do_catchsql_test(
> +    "alter-9.2",
> +    [[
> +        CREATE VIEW v AS SELECT * FROM test;
> +        ALTER TABLE v ADD b INTEGER;
> +    ]], {
> +        -- <alter-9.2>
> +        1,"Can't add column 'B' to the view 'V'"
> +        -- </alter-9.2>
> +    })
> +
> +test:do_execsql_test(
> +    "alter-9.3",
> +    [[
> +        ALTER TABLE test ADD c TEXT NOT NULL DEFAULT ('a') COLLATE "unicode_ci";
> +    ]], {
> +        -- <alter-9.3>
> +        -- </alter-9.3>
> +    })
> +
> +test:do_execsql_test(
> +    "alter-9.4",
> +    [[
> +        INSERT INTO test(a, b) VALUES (1, 1);
> +        SELECT * FROM test;
> +    ]], {
> +        -- <alter-9.4>
> +        1,1,"a"
> +        -- </alter-9.4>
> +    })
> +
> +test:do_catchsql_test(
> +    "alter-9.5",
> +    [[
> +        INSERT INTO test VALUES (2, 2, NULL);
> +    ]], {
> +        -- <alter-9.5>
> +        1,"Failed to execute SQL statement: NOT NULL constraint failed: TEST.C"
> +                -- </alter-9.5>
> +    })
> +
> +test:do_execsql_test(
> +    "alter-9.6",
> +    [[
> +        SELECT * FROM test WHERE c LIKE 'A';
> +    ]], {
> +        -- <alter-9.6>
> +        1,1,"a"
> +        -- </alter-9.6>
> +    })
> +
> +test:do_catchsql_test(
> +    "alter-9.7",
> +    [[
> +        ALTER TABLE test ADD d INTEGER;
> +    ]], {
> +        -- <alter-9.7>
> +        1,"Tuple field count 3 does not match space field count 4"
> +        -- </alter-9.7>
> +    })
> +
> test:finish_test()
> -- 
> 2.21.0 (Apple Git-122)
>