MDEV-8931: (server part of) session state tracking

initial commit to test

Author: sanja-byelkin

include/mysql.h.pp

@@ -87,6 +87,15 @@
   MYSQL_OPTION_MULTI_STATEMENTS_ON,
   MYSQL_OPTION_MULTI_STATEMENTS_OFF
 };
+enum enum_session_state_type
+{
+  SESSION_TRACK_SYSTEM_VARIABLES,
+  SESSION_TRACK_SCHEMA,
+  SESSION_TRACK_STATE_CHANGE,
+  SESSION_TRACK_GTIDS,
+  SESSION_TRACK_TRANSACTION_CHARACTERISTICS,
+  SESSION_TRACK_TRANSACTION_STATE
+};
 my_bool my_net_init(NET *net, Vio* vio, void *thd, unsigned int my_flags);
 void my_net_local_init(NET *net);
 void net_end(NET *net);

include/mysql_com.h

@@ -72,6 +72,14 @@
 #define INDEX_COMMENT_MAXLEN 1024
 #define TABLE_PARTITION_COMMENT_MAXLEN 1024
 
+/*
+  Maximum length of protocol packet.
+  OK packet length limit also restricted to this value as any length greater
+  than this value will have first byte of OK packet to be 254 thus does not
+  provide a means to identify if this is OK or EOF packet.
+*/
+#define MAX_PACKET_LENGTH (256L*256L*256L-1)
+
 /*
   USER_HOST_BUFF_SIZE -- length of string buffer, that is enough to contain
   username and hostname parts of the user identifier with trailing zero in
@@ -221,6 +229,14 @@ enum enum_server_command
 /* Don't close the connection for a connection with expired password. */
 #define CLIENT_CAN_HANDLE_EXPIRED_PASSWORDS (1UL << 22)
 
+/**
+  Capable of handling server state change information. Its a hint to the
+  server to include the state change information in Ok packet.
+*/
+#define CLIENT_SESSION_TRACK (1UL << 23)
+/* Client no longer needs EOF packet */
+#define CLIENT_DEPRECATE_EOF (1UL << 24)
+
 #define CLIENT_PROGRESS_OBSOLETE  (1UL << 29)
 #define CLIENT_SSL_VERIFY_SERVER_CERT (1UL << 30)
 /*
@@ -272,10 +288,12 @@ enum enum_server_command
                            CLIENT_MULTI_RESULTS | \
                            CLIENT_PS_MULTI_RESULTS | \
                            CLIENT_SSL_VERIFY_SERVER_CERT | \
-                           CLIENT_REMEMBER_OPTIONS | \
+                            CLIENT_REMEMBER_OPTIONS | \
                            MARIADB_CLIENT_PROGRESS | \
                            CLIENT_PLUGIN_AUTH | \
                            CLIENT_PLUGIN_AUTH_LENENC_CLIENT_DATA | \
+                           CLIENT_SESSION_TRACK |\
+                           CLIENT_DEPRECATE_EOF |\
                            CLIENT_CONNECT_ATTRS |\
                            MARIADB_CLIENT_COM_MULTI)
 
@@ -340,6 +358,11 @@ enum enum_server_command
 */
 #define SERVER_STATUS_IN_TRANS_READONLY 8192
 
+/**
+  This status flag, when on, implies that one of the state information has
+  changed on the server because of the execution of the last statement.
+*/
+#define SERVER_SESSION_STATE_CHANGED (1UL << 14)
 
 /**
   Server status flags that must be cleared when starting
@@ -356,7 +379,8 @@ enum enum_server_command
                                  SERVER_QUERY_WAS_SLOW |\
                                  SERVER_STATUS_DB_DROPPED |\
                                  SERVER_STATUS_CURSOR_EXISTS|\
-                                 SERVER_STATUS_LAST_ROW_SENT)
+                                 SERVER_STATUS_LAST_ROW_SENT|\
+                                 SERVER_SESSION_STATE_CHANGED)
 
 #define MYSQL_ERRMSG_SIZE	512
 #define NET_READ_TIMEOUT	30		/* Timeout on read */
@@ -523,6 +547,30 @@ enum enum_mysql_set_option
   MYSQL_OPTION_MULTI_STATEMENTS_OFF
 };
 
+/*
+  Type of state change information that the server can include in the Ok
+  packet.
+  Note : 1) session_state_type shouldn't go past 255 (i.e. 1-byte boundary).
+         2) Modify the definition of SESSION_TRACK_END when a new member is
+	    added.
+*/
+enum enum_session_state_type
+{
+  SESSION_TRACK_SYSTEM_VARIABLES,                       /* Session system variables */
+  SESSION_TRACK_SCHEMA,                          /* Current schema */
+  SESSION_TRACK_STATE_CHANGE,                  /* track session state changes */
+  SESSION_TRACK_GTIDS,
+  SESSION_TRACK_TRANSACTION_CHARACTERISTICS,  /* Transaction chistics */
+  SESSION_TRACK_TRANSACTION_STATE             /* Transaction state */
+};
+
+#define SESSION_TRACK_BEGIN SESSION_TRACK_SYSTEM_VARIABLES
+
+#define SESSION_TRACK_END SESSION_TRACK_TRANSACTION_STATE
+
+#define IS_SESSION_STATE_TYPE(T) \
+  (((int)(T) >= SESSION_TRACK_BEGIN) && ((T) <= SESSION_TRACK_END))
+
 #define net_new_transaction(net) ((net)->pkt_nr=0)
 
 #ifdef __cplusplus
@@ -641,6 +689,7 @@ my_ulonglong net_field_length_ll(uchar **packet);
 my_ulonglong safe_net_field_length_ll(uchar **packet, size_t packet_len);
 uchar *net_store_length(uchar *pkg, ulonglong length);
 uchar *safe_net_store_length(uchar *pkg, size_t pkg_len, ulonglong length);
+unsigned int net_length_size(ulonglong num);
 #endif
 
 #ifdef __cplusplus

libmysqld/CMakeLists.txt

@@ -112,6 +112,7 @@ SET(SQL_EMBEDDED_SOURCES emb_qcache.cc libmysqld.c lib_sql.cc
            ../sql/item_windowfunc.cc ../sql/sql_window.cc
            ../sql/sql_cte.cc
            ../sql/temporary_tables.cc
+           ../sql/session_tracker.cc
            ${GEN_SOURCES}
            ${MYSYS_LIBWRAP_SOURCE}
 )

libmysqld/lib_sql.cc

@@ -1172,7 +1172,8 @@ bool
 net_send_ok(THD *thd,
             uint server_status, uint statement_warn_count,
             ulonglong affected_rows, ulonglong id, const char *message,
-            bool unused __attribute__((unused)))
+            bool unused1 __attribute__((unused)),
+            bool unused2 __attribute__((unused)))
 {
   DBUG_ENTER("emb_net_send_ok");
   MYSQL_DATA *data;

mysql-test/r/mysqld--help.result

@@ -903,6 +903,11 @@ The following options may be given as the first argument:
  files within specified directory
  --server-id=#       Uniquely identifies the server instance in the community
  of replication partners
+ --session-track-schema 
+ Track changes to the 'default schema'.
+ (Defaults to on; use --skip-session-track-schema to disable.)
+ --session-track-state-change 
+ Track changes to the 'session state'.
  --show-slave-auth-info 
  Show user and password in SHOW SLAVE HOSTS on this
  master.
@@ -1385,6 +1390,8 @@ safe-user-create FALSE
 secure-auth TRUE
 secure-file-priv (No default value)
 server-id 1
+session-track-schema TRUE
+session-track-state-change FALSE
 show-slave-auth-info FALSE
 silent-startup FALSE
 skip-grant-tables TRUE

mysql-test/suite/sys_vars/r/sysvars_server_embedded.result

@@ -3327,6 +3327,34 @@ NUMERIC_BLOCK_SIZE	1
 ENUM_VALUE_LIST	NULL
 READ_ONLY	NO
 COMMAND_LINE_ARGUMENT	REQUIRED
+VARIABLE_NAME	SESSION_TRACK_SCHEMA
+SESSION_VALUE	ON
+GLOBAL_VALUE	ON
+GLOBAL_VALUE_ORIGIN	COMPILE-TIME
+DEFAULT_VALUE	ON
+VARIABLE_SCOPE	SESSION
+VARIABLE_TYPE	BOOLEAN
+VARIABLE_COMMENT	Track changes to the 'default schema'.
+NUMERIC_MIN_VALUE	NULL
+NUMERIC_MAX_VALUE	NULL
+NUMERIC_BLOCK_SIZE	NULL
+ENUM_VALUE_LIST	OFF,ON
+READ_ONLY	NO
+COMMAND_LINE_ARGUMENT	OPTIONAL
+VARIABLE_NAME	SESSION_TRACK_STATE_CHANGE
+SESSION_VALUE	OFF
+GLOBAL_VALUE	OFF
+GLOBAL_VALUE_ORIGIN	COMPILE-TIME
+DEFAULT_VALUE	OFF
+VARIABLE_SCOPE	SESSION
+VARIABLE_TYPE	BOOLEAN
+VARIABLE_COMMENT	Track changes to the 'session state'.
+NUMERIC_MIN_VALUE	NULL
+NUMERIC_MAX_VALUE	NULL
+NUMERIC_BLOCK_SIZE	NULL
+ENUM_VALUE_LIST	OFF,ON
+READ_ONLY	NO
+COMMAND_LINE_ARGUMENT	OPTIONAL
 VARIABLE_NAME	SKIP_EXTERNAL_LOCKING
 SESSION_VALUE	NULL
 GLOBAL_VALUE	ON

mysql-test/suite/sys_vars/r/sysvars_server_notembedded.result

@@ -3789,6 +3789,34 @@ NUMERIC_BLOCK_SIZE	1
 ENUM_VALUE_LIST	NULL
 READ_ONLY	NO
 COMMAND_LINE_ARGUMENT	REQUIRED
+VARIABLE_NAME	SESSION_TRACK_SCHEMA
+SESSION_VALUE	ON
+GLOBAL_VALUE	ON
+GLOBAL_VALUE_ORIGIN	COMPILE-TIME
+DEFAULT_VALUE	ON
+VARIABLE_SCOPE	SESSION
+VARIABLE_TYPE	BOOLEAN
+VARIABLE_COMMENT	Track changes to the 'default schema'.
+NUMERIC_MIN_VALUE	NULL
+NUMERIC_MAX_VALUE	NULL
+NUMERIC_BLOCK_SIZE	NULL
+ENUM_VALUE_LIST	OFF,ON
+READ_ONLY	NO
+COMMAND_LINE_ARGUMENT	OPTIONAL
+VARIABLE_NAME	SESSION_TRACK_STATE_CHANGE
+SESSION_VALUE	OFF
+GLOBAL_VALUE	OFF
+GLOBAL_VALUE_ORIGIN	COMPILE-TIME
+DEFAULT_VALUE	OFF
+VARIABLE_SCOPE	SESSION
+VARIABLE_TYPE	BOOLEAN
+VARIABLE_COMMENT	Track changes to the 'session state'.
+NUMERIC_MIN_VALUE	NULL
+NUMERIC_MAX_VALUE	NULL
+NUMERIC_BLOCK_SIZE	NULL
+ENUM_VALUE_LIST	OFF,ON
+READ_ONLY	NO
+COMMAND_LINE_ARGUMENT	OPTIONAL
 VARIABLE_NAME	SKIP_EXTERNAL_LOCKING
 SESSION_VALUE	NULL
 GLOBAL_VALUE	ON

sql-common/pack.c

@@ -186,3 +186,25 @@ uchar *safe_net_store_length(uchar *packet, size_t packet_len, ulonglong length)
   return packet+8;
 }
 
+
+/**
+  The length of space required to store the resulting length-encoded integer
+  for the given number. This function can be used at places where one needs to
+  dynamically allocate the buffer for a given number to be stored as length-
+  encoded integer.
+
+  @param num [IN]   the input number
+
+  @return length of buffer needed to store this number [1, 3, 4, 9].
+*/
+
+uint net_length_size(ulonglong num)
+{
+  if (num < (ulonglong) 251LL)
+    return 1;
+  if (num < (ulonglong) 65536LL)
+    return 3;
+  if (num < (ulonglong) 16777216LL)
+    return 4;
+  return 9;
+}

sql/CMakeLists.txt

@@ -95,7 +95,9 @@ SET (SQL_SOURCE
                ../sql-common/client_plugin.c
                opt_range.cc opt_range.h opt_sum.cc 
                ../sql-common/pack.c parse_file.cc password.c procedure.cc 
-               protocol.cc records.cc repl_failsafe.cc rpl_filter.cc set_var.cc 
+               protocol.cc records.cc repl_failsafe.cc rpl_filter.cc
+               session_tracker.cc
+               set_var.cc 
                slave.cc sp.cc sp_cache.cc sp_head.cc sp_pcontext.cc 
                sp_rcontext.cc spatial.cc sql_acl.cc sql_analyse.cc sql_base.cc 
                sql_cache.cc sql_class.cc sql_client.cc sql_crypt.cc sql_crypt.h 

sql/net_serv.cc

@@ -117,7 +117,6 @@ extern my_bool thd_net_is_killed();
 #endif
 
 #define TEST_BLOCKING		8
-#define MAX_PACKET_LENGTH (256L*256L*256L-1)
 
 static my_bool net_write_buff(NET *, const uchar *, ulong);