Add DB_METADATA to INFORMATION_SCHEMA.SCHEMATA

Summary: Add DB_METADATA to INFORMATION_SCHEMA.SCHEMATA for each database for easy query by OLM

Test Plan:
1. Test manually by inspecting SCHEMATA

Result:
https://phabricator.intern.facebook.com/P60466869

2. Update test case (TODO)

Reviewers: herman, lcai

Reviewed By: herman

Subscribers: butterflybot, webscalesql-eng@fb.com

Differential Revision: https://phabricator.intern.facebook.com/D13510326

Tasks: T37428915

Tags: bootcamp

Signature: 13510326:1546451545:62ec37297de59dde87229dfa922570fa510c45e3

mysql-test/r/information_schema-big.result

@@ -66,6 +66,7 @@ USER_STATISTICS	USER_NAME
 VIEWS	TABLE_SCHEMA
 AUTHINFO	ID
 SLAVE_DB_LOAD	DB
+SCHEMATA_EXT	SCHEMA_NAME
 SELECT t.table_name, c1.column_name
 FROM information_schema.tables t
 INNER JOIN
@@ -129,3 +130,4 @@ USER_STATISTICS	USER_NAME
 VIEWS	TABLE_SCHEMA
 AUTHINFO	ID
 SLAVE_DB_LOAD	DB
+SCHEMATA_EXT	SCHEMA_NAME

mysql-test/r/information_schema.result

@@ -98,6 +98,7 @@ USER_STATISTICS
 VIEWS
 AUTHINFO
 SLAVE_DB_LOAD
+SCHEMATA_EXT
 columns_priv
 db
 event
@@ -939,7 +940,7 @@ table_schema IN ('mysql', 'INFORMATION_SCHEMA', 'test', 'mysqltest')
 AND table_name not like 'ndb%' AND table_name not like 'innodb_%'  AND table_name not like 'rocksdb_%'
 GROUP BY TABLE_SCHEMA;
 table_schema	count(*)
-information_schema	45
+information_schema	46
 mysql	27
 create table t1 (i int, j int);
 create trigger trg1 before insert on t1 for each row
@@ -1407,6 +1408,7 @@ QUERY_PERF_COUNTER	information_schema.QUERY_PERF_COUNTER	1
 REFERENTIAL_CONSTRAINTS	information_schema.REFERENTIAL_CONSTRAINTS	1
 ROUTINES	information_schema.ROUTINES	1
 SCHEMATA	information_schema.SCHEMATA	1
+SCHEMATA_EXT	information_schema.SCHEMATA_EXT	1
 SCHEMA_PRIVILEGES	information_schema.SCHEMA_PRIVILEGES	1
 SESSION_STATUS	information_schema.SESSION_STATUS	1
 SESSION_VARIABLES	information_schema.SESSION_VARIABLES	1

mysql-test/r/information_schema_db.result

@@ -50,6 +50,7 @@ USER_STATISTICS
 VIEWS
 AUTHINFO
 SLAVE_DB_LOAD
+SCHEMATA_EXT
 show tables from INFORMATION_SCHEMA like 'T%';
 Tables_in_information_schema (T%)
 TRANSACTION_LIST

mysql-test/r/mysqlshow.result

@@ -146,6 +146,7 @@ DROP TABLE t1, t2;
 | ROCKSDB_TRX                           |
 | ROUTINES                              |
 | SCHEMATA                              |
+| SCHEMATA_EXT                          |
 | SCHEMA_PRIVILEGES                     |
 | SESSION_STATUS                        |
 | SESSION_VARIABLES                     |
@@ -234,6 +235,7 @@ DROP TABLE t1, t2;
 | ROCKSDB_TRX                           |
 | ROUTINES                              |
 | SCHEMATA                              |
+| SCHEMATA_EXT                          |
 | SCHEMA_PRIVILEGES                     |
 | SESSION_STATUS                        |
 | SESSION_VARIABLES                     |

mysql-test/suite/funcs_1/r/is_columns_is.result

@@ -287,6 +287,9 @@ def	information_schema	SCHEMATA	DEFAULT_CHARACTER_SET_NAME	3		NO	varchar	32	96	N
 def	information_schema	SCHEMATA	DEFAULT_COLLATION_NAME	4		NO	varchar	32	96	NULL	NULL	NULL	utf8	utf8_general_ci	varchar(32)			select	
 def	information_schema	SCHEMATA	SCHEMA_NAME	2		NO	varchar	64	192	NULL	NULL	NULL	utf8	utf8_general_ci	varchar(64)			select	
 def	information_schema	SCHEMATA	SQL_PATH	5	NULL	YES	varchar	512	1536	NULL	NULL	NULL	utf8	utf8_general_ci	varchar(512)			select	
+def	information_schema	SCHEMATA_EXT	CATALOG_NAME	1		NO	varchar	512	1536	NULL	NULL	NULL	utf8	utf8_general_ci	varchar(512)			select	
+def	information_schema	SCHEMATA_EXT	DB_METADATA	3		NO	varchar	1024	3072	NULL	NULL	NULL	utf8	utf8_general_ci	varchar(1024)			select	
+def	information_schema	SCHEMATA_EXT	SCHEMA_NAME	2		NO	varchar	64	192	NULL	NULL	NULL	utf8	utf8_general_ci	varchar(64)			select	
 def	information_schema	SCHEMA_PRIVILEGES	GRANTEE	1		NO	varchar	81	243	NULL	NULL	NULL	utf8	utf8_general_ci	varchar(81)			select	
 def	information_schema	SCHEMA_PRIVILEGES	IS_GRANTABLE	5		NO	varchar	3	9	NULL	NULL	NULL	utf8	utf8_general_ci	varchar(3)			select	
 def	information_schema	SCHEMA_PRIVILEGES	PRIVILEGE_TYPE	4		NO	varchar	64	192	NULL	NULL	NULL	utf8	utf8_general_ci	varchar(64)			select	
@@ -918,6 +921,9 @@ NULL	information_schema	ROUTINES	LAST_ALTERED	datetime	NULL	NULL	NULL	NULL	datet
 3.0000	information_schema	SCHEMATA	DEFAULT_CHARACTER_SET_NAME	varchar	32	96	utf8	utf8_general_ci	varchar(32)
 3.0000	information_schema	SCHEMATA	DEFAULT_COLLATION_NAME	varchar	32	96	utf8	utf8_general_ci	varchar(32)
 3.0000	information_schema	SCHEMATA	SQL_PATH	varchar	512	1536	utf8	utf8_general_ci	varchar(512)
+3.0000	information_schema	SCHEMATA_EXT	CATALOG_NAME	varchar	512	1536	utf8	utf8_general_ci	varchar(512)
+3.0000	information_schema	SCHEMATA_EXT	SCHEMA_NAME	varchar	64	192	utf8	utf8_general_ci	varchar(64)
+3.0000	information_schema	SCHEMATA_EXT	DB_METADATA	varchar	1024	3072	utf8	utf8_general_ci	varchar(1024)
 3.0000	information_schema	SCHEMA_PRIVILEGES	GRANTEE	varchar	81	243	utf8	utf8_general_ci	varchar(81)
 3.0000	information_schema	SCHEMA_PRIVILEGES	TABLE_CATALOG	varchar	512	1536	utf8	utf8_general_ci	varchar(512)
 3.0000	information_schema	SCHEMA_PRIVILEGES	TABLE_SCHEMA	varchar	64	192	utf8	utf8_general_ci	varchar(64)

mysql-test/suite/funcs_1/r/is_tables_is.result

@@ -636,6 +636,29 @@ user_comment
 Separator	-----------------------------------------------------
 TABLE_CATALOG	def
 TABLE_SCHEMA	information_schema
+TABLE_NAME	SCHEMATA_EXT
+TABLE_TYPE	SYSTEM VIEW
+ENGINE	MEMORY
+VERSION	10
+ROW_FORMAT	Fixed
+TABLE_ROWS	#TBLR#
+AVG_ROW_LENGTH	#ARL#
+DATA_LENGTH	#DL#
+MAX_DATA_LENGTH	#MDL#
+INDEX_LENGTH	#IL#
+DATA_FREE	#DF#
+AUTO_INCREMENT	NULL
+CREATE_TIME	#CRT#
+UPDATE_TIME	#UT#
+CHECK_TIME	#CT#
+TABLE_COLLATION	utf8_general_ci
+CHECKSUM	NULL
+CREATE_OPTIONS	#CO#
+TABLE_COMMENT	#TC#
+user_comment	
+Separator	-----------------------------------------------------
+TABLE_CATALOG	def
+TABLE_SCHEMA	information_schema
 TABLE_NAME	SCHEMA_PRIVILEGES
 TABLE_TYPE	SYSTEM VIEW
 ENGINE	MEMORY
@@ -1665,6 +1688,29 @@ user_comment
 Separator	-----------------------------------------------------
 TABLE_CATALOG	def
 TABLE_SCHEMA	information_schema
+TABLE_NAME	SCHEMATA_EXT
+TABLE_TYPE	SYSTEM VIEW
+ENGINE	MEMORY
+VERSION	10
+ROW_FORMAT	Fixed
+TABLE_ROWS	#TBLR#
+AVG_ROW_LENGTH	#ARL#
+DATA_LENGTH	#DL#
+MAX_DATA_LENGTH	#MDL#
+INDEX_LENGTH	#IL#
+DATA_FREE	#DF#
+AUTO_INCREMENT	NULL
+CREATE_TIME	#CRT#
+UPDATE_TIME	#UT#
+CHECK_TIME	#CT#
+TABLE_COLLATION	utf8_general_ci
+CHECKSUM	NULL
+CREATE_OPTIONS	#CO#
+TABLE_COMMENT	#TC#
+user_comment	
+Separator	-----------------------------------------------------
+TABLE_CATALOG	def
+TABLE_SCHEMA	information_schema
 TABLE_NAME	SCHEMA_PRIVILEGES
 TABLE_TYPE	SYSTEM VIEW
 ENGINE	MEMORY

mysql-test/t/db_metadata.test

@@ -42,41 +42,49 @@ show create database test4;
 create database test5 db_metadata = "{\"shard\":\"test5_shard\"}";
 show create database test5;
 --exec cat $MYSQLD_DATADIR/test5/db.opt
+select catalog_name, schema_name, db_metadata from information_schema.schemata_ext;
 
 # verify show create is valid
 --let $db_create=query_get_value(show create database test5, 'Create Database', 1)
 drop database test5;
 eval $db_create;
 show create database test5;
 --exec cat $MYSQLD_DATADIR/test5/db.opt
+select catalog_name, schema_name, db_metadata from information_schema.schemata_ext;
 
 # create database with character set and db metadata
 create database test6 character set utf8 db_metadata = "{\"shard\":\"test6_shard\"}";
 show create database test6;
 --exec cat $MYSQLD_DATADIR/test6/db.opt
+select catalog_name, schema_name, db_metadata from information_schema.schemata_ext;
 
 # create database with read only and db metadata
 create database test7 read_only = true db_metadata = "{\"shard\":\"test7_shard\"}";
 show create database test7;
 --exec cat $MYSQLD_DATADIR/test7/db.opt
+select catalog_name, schema_name, db_metadata from information_schema.schemata_ext;
 
 # create database with character set and read only
 create database test8 character set utf8 read_only = true;
 show create database test8;
 --exec cat $MYSQLD_DATADIR/test8/db.opt
+select catalog_name, schema_name, db_metadata from information_schema.schemata_ext;
 
 # create database with character set, read only and db metadata
 create database test9 character set utf8 read_only = true db_metadata = "{\"shard\":\"test9_shard\"}";
 show create database test9;
 --exec cat $MYSQLD_DATADIR/test9/db.opt
+select catalog_name, schema_name, db_metadata from information_schema.schemata_ext;
 
 # create database with invalid JSON string for db_metadata
 --error ER_DB_METADATA_INVALID_JSON
 create database test10 db_metadata = "invalid_json";
+select catalog_name, schema_name, db_metadata from information_schema.schemata_ext;
 
 # create database with single quotation
 --error ER_DB_METADATA_INVALID_JSON
 create database test11 db_metadata = "{\'shard\':\'test11_shard\'}";
+select catalog_name, schema_name, db_metadata from information_schema.schemata_ext;
 
 # create database with double quote around metadata with single and double quotes in value
 create database test12 db_metadata = "{\"sha'rd\":\"test12\\\"_shard\"}";
@@ -107,6 +115,7 @@ show create database test3;
 alter database test3 db_metadata = "{\"shard\":\"test3_shard_altered\"}";
 show create database test3;
 --exec cat $MYSQLD_DATADIR/test3/db.opt
+select catalog_name, schema_name, db_metadata from information_schema.schemata_ext;
 
 # alter database read only
 alter database test4 read_only = true;
@@ -117,6 +126,7 @@ show create database test4;
 alter database test4 db_metadata = "{\"shard\":\"test4_shard_altered\"}";
 show create database test4;
 --exec cat $MYSQLD_DATADIR/test4/db.opt
+select catalog_name, schema_name, db_metadata from information_schema.schemata_ext;
 
 # alter database read only
 alter database test4 read_only = false;
@@ -127,6 +137,7 @@ show create database test4;
 alter database test5 db_metadata = "{\"shard\":\"test5_shard_altered\"}";
 show create database test5;
 --exec cat $MYSQLD_DATADIR/test5/db.opt
+select catalog_name, schema_name, db_metadata from information_schema.schemata_ext;
 
 # alter database character set but keep db metadata intact
 alter database test5 character set ascii;
@@ -147,11 +158,13 @@ show create database test5;
 alter database test5 db_metadata "";
 show create database test5;
 --exec cat $MYSQLD_DATADIR/test5/db.opt
+select catalog_name, schema_name, db_metadata from information_schema.schemata_ext;
 
 # alter database set db metadata to max length string
 alter database test5 db_metadata "{\"shard\":\"Really long shard name. Really long shard name. Really long shard name. Really long shard name. Really long shard name. Really long shard name. Really long shard name. Really long shard name. Really long shard name. Really long shard name. Really long shard name. Really long shard name. Really long shard name. Really long shard name. Really long shard name. Really long shard name. Really long shard name. Really long shard name. Really long shard name. Really long shard name. Really long shard name. Really long shard name. Really long shard name. Really long shard name. Really long shard name. Really long shard name. Really long shard name. Really long shard name. Really long shard name. Really long shard name. Really long shard name. Really long shard name. Really long shard name. Really long shard name. Really long shard name. Really long shard name. Really long shard name. Really long shard name. Really long shard name. Really long shard name. Really long shard name. Really long shard name. Fin\"}";
 show create database test5;
 --exec cat $MYSQLD_DATADIR/test5/db.opt
+select catalog_name, schema_name, db_metadata from information_schema.schemata_ext;
 
 # verify show create is valid
 --let $db_create=query_get_value(show create database test5, 'Create Database', 1)
@@ -163,36 +176,43 @@ show create database test5;
 # alter database exceed db metadata max length
 --error ER_DB_METADATA_TOO_LONG
 alter database test5 db_metadata "{\"shard\":\"Really long shard name. Really long shard name. Really long shard name. Really long shard name. Really long shard name. Really long shard name. Really long shard name. Really long shard name. Really long shard name. Really long shard name. Really long shard name. Really long shard name. Really long shard name. Really long shard name. Really long shard name. Really long shard name. Really long shard name. Really long shard name. Really long shard name. Really long shard name. Really long shard name. Really long shard name. Really long shard name. Really long shard name. Really long shard name. Really long shard name. Really long shard name. Really long shard name. Really long shard name. Really long shard name. Really long shard name. Really long shard name. Really long shard name. Really long shard name. Really long shard name. Really long shard name. Really long shard name. Really long shard name. Really long shard name. Really long shard name. Really long shard name. Really long shard name. Really long shard name. Fin\"}";
+select catalog_name, schema_name, db_metadata from information_schema.schemata_ext;
 
 # alter database character set and db metadata
 alter database test6 character set ascii db_metadata = "{\"shard\":\"test6_shard_altered\"}";
 show create database test6;
 --exec cat $MYSQLD_DATADIR/test6/db.opt
+select catalog_name, schema_name, db_metadata from information_schema.schemata_ext;
 
 # alter database read only and db metadata
 alter database test7 read_only = true db_metadata = "{\"shard\":\"test7_shard_altered\"}";
 show create database test7;
 --exec cat $MYSQLD_DATADIR/test7/db.opt
+select catalog_name, schema_name, db_metadata from information_schema.schemata_ext;
 
 # alter database character set and read only
 alter database test8 character set ascii read_only = true;
 show create database test8;
 --exec cat $MYSQLD_DATADIR/test8/db.opt
+select catalog_name, schema_name, db_metadata from information_schema.schemata_ext;
 
 # alter database character set, read only and db metadata
 alter database test9 character set ascii read_only = true db_metadata = "{\"shard\":\"test9_shard_altered\"}";
 show create database test9;
 --exec cat $MYSQLD_DATADIR/test9/db.opt
+select catalog_name, schema_name, db_metadata from information_schema.schemata_ext;
 
 # ensure information_schema and mysql tables are intact
 show create database information_schema;
 show create database mysql;
 --error ER_DBACCESS_DENIED_ERROR
 alter database information_schema db_metadata "{\"shard\":\"is_shard\"}";
+select catalog_name, schema_name, db_metadata from information_schema.schemata_ext;
 
 # alter database with invalid JSON string for db_metadata
 --error ER_DB_METADATA_INVALID_JSON
 alter database test9 db_metadata = "invalid_json";
+select catalog_name, schema_name, db_metadata from information_schema.schemata_ext;
 
 # create database without any options
 create database test10;
@@ -208,6 +228,7 @@ show create database test10;
 alter database test10 db_metadata = "{\"shard\":\"test10_shard_altered\"}";
 show create database test10;
 --exec cat $MYSQLD_DATADIR/test10/db.opt
+select catalog_name, schema_name, db_metadata from information_schema.schemata_ext;
 
 # alter database read only
 alter database test10 read_only = false;

sql/handler.h

@@ -1131,15 +1131,14 @@ enum enum_db_read_only { DB_READ_ONLY_NO = 0,
                          DB_READ_ONLY_SUPER = 2,
                          DB_READ_ONLY_NULL = 255 };
 
-typedef struct st_ha_create_information
+struct st_ha_create_information_base
 {
   const CHARSET_INFO *table_charset, *default_table_charset;
   bool alter_default_table_charset; /* This is to differentiate whether the
                                        null value for default_table_charset
                                        means it is explicitly set to default or
                                        it is not specified in alter */
   enum enum_db_read_only db_read_only;
-  String db_metadata;
   bool alter_db_metadata;  /* This is to differentiate whether the null value
                               for db_metadata means it is explicitly set to
                               default or it is not specified in alter */
@@ -1157,7 +1156,6 @@ typedef struct st_ha_create_information
   uint stats_sample_pages;		/* number of pages to sample during
 					stats estimation, if used, otherwise 0. */
   enum_stats_auto_recalc stats_auto_recalc;
-  SQL_I_List<TABLE_LIST> merge_list;
   handlerton *db_type;
   /**
     Row type of the table definition.
@@ -1177,9 +1175,22 @@ typedef struct st_ha_create_information
   enum ha_storage_media storage_media;  /* DEFAULT, DISK or MEMORY */
   bool rbr_column_names; /* If true, column names for this table are logged
                             in Table_map_log_events */
+};
+
+typedef struct st_ha_create_information : public st_ha_create_information_base
+{
+  String db_metadata;
+  SQL_I_List<TABLE_LIST> merge_list;
 
   /* initialize db_read_only parameter */
-  st_ha_create_information() : db_read_only(DB_READ_ONLY_NO) {}
+  st_ha_create_information()
+  {
+    // memset the base struct with POD fields
+    memset(
+      (st_ha_create_information_base *)this,
+      0,
+      sizeof(st_ha_create_information_base));
+  }
 } HA_CREATE_INFO;
 
 /**

sql/sql_db.cc

@@ -667,7 +667,6 @@ bool load_db_opt(THD *thd, const char *path, HA_CREATE_INFO *create,
   bool error=1;
   uint nbytes;
 
-  memset(create, 0, sizeof(*create));
   create->default_table_charset= thd->variables.collation_server;
 
   /* Check if options for this database are already in the hash */