storagemanager, mod_storage_sql, mod_storage_sql2: Rename mod_storage_sql2 -> mod_storage_sql, mod_storage_sql -> mod_storage_sql1 (temporarily), and emit warning for configs using sql2

4 files changed, 766 insertions, 750 deletions

diff --git a/core/storagemanager.lua b/core/storagemanager.lua
index 21f5fd1d..c312cf05 100644
--- a/core/storagemanager.lua
+++ b/core/storagemanager.lua
@@ -58,7 +58,23 @@ local function load_driver(host, driver_name)
 end
 
 local function get_storage_config(host)
-	return config.get(host, "storage");
+	-- COMPAT w/ unreleased Prosody 0.10 and the once-experimental mod_storage_sql2 in peoples' config files
+	local storage_config = config.get(host, "storage");
+	local found_sql2;
+	if storage_config == "sql2" then
+		storage_config, found_sql2 = "sql", true;
+	elseif type(storage_config) == "table" then
+		for store_name, driver_name in pairs(storage_config) do
+			if driver_name == "sql2" then
+				storage_config[store_name] = "sql";
+				found_sql2 = true;
+			end
+		end
+	end
+	if found_sql2 then
+		log("error", "The temporary 'sql2' storage module has now been renamed to 'sql', please update your config file: https://prosody.im/doc/modules/mod_storage_sql2");
+	end
+	return storage_config;
 end
 
 local function get_driver(host, store)
diff --git a/plugins/mod_storage_sql.lua b/plugins/mod_storage_sql.lua
index a5bb5bfa..7695e15d 100644
--- a/plugins/mod_storage_sql.lua
+++ b/plugins/mod_storage_sql.lua
@@ -1,184 +1,36 @@
 
---[[
-
-DB Tables:
-	Prosody - key-value, map
-		| host | user | store | key | type | value |
-	ProsodyArchive - list
-		| host | user | store | key | time | stanzatype | jsonvalue |
-
-Mapping:
-	Roster - Prosody
-		| host | user | "roster" | "contactjid" | type | value |
-		| host | user | "roster" | NULL | "json" | roster[false] data |
-	Account - Prosody
-		| host | user | "accounts" | "username" | type | value |
-
-	Offline - ProsodyArchive
-		| host | user | "offline" | "contactjid" | time | "message" | json|XML |
-
-]]
-
-local type = type;
-local tostring = tostring;
-local tonumber = tonumber;
-local pairs = pairs;
-local next = next;
-local setmetatable = setmetatable;
-local xpcall = xpcall;
 local json = require "util.json";
-local build_url = require"socket.url".build;
-
-local DBI;
-local connection;
-local host,user,store = module.host;
-local params = module:get_option("sql");
-
-local dburi;
-local connections = module:shared "/*/sql/connection-cache";
-
-local function db2uri(params)
-	return build_url{
-		scheme = params.driver,
-		user = params.username,
-		password = params.password,
-		host = params.host,
-		port = params.port,
-		path = params.database,
-	};
-end
-
-
+local sql = require "util.sql";
+local xml_parse = require "util.xml".parse;
+local uuid = require "util.uuid";
 local resolve_relative_path = require "util.paths".resolve_relative_path;
 
-local function test_connection()
-	if not connection then return nil; end
-	if connection:ping() then
-		return true;
-	else
-		module:log("debug", "Database connection closed");
-		connection = nil;
-		connections[dburi] = nil;
-	end
-end
-local function connect()
-	if not test_connection() then
-		prosody.unlock_globals();
-		local dbh, err = DBI.Connect(
-			params.driver, params.database,
-			params.username, params.password,
-			params.host, params.port
-		);
-		prosody.lock_globals();
-		if not dbh then
-			module:log("debug", "Database connection failed: %s", tostring(err));
-			return nil, err;
+local stanza_mt = require"util.stanza".stanza_mt;
+local getmetatable = getmetatable;
+local t_concat = table.concat;
+local function is_stanza(x) return getmetatable(x) == stanza_mt; end
+
+local noop = function() end
+local unpack = unpack
+local function iterator(result)
+	return function(result_)
+		local row = result_();
+		if row ~= nil then
+			return unpack(row);
 		end
-		module:log("debug", "Successfully connected to database");
-		dbh:autocommit(false); -- don't commit automatically
-		connection = dbh;
-
-		connections[dburi] = dbh;
-	end
-	return connection;
+	end, result, nil;
 end
 
-local function create_table()
-	if not module:get_option("sql_manage_tables", true) then
-		return;
-	end
-	local create_sql = "CREATE TABLE `prosody` (`host` TEXT, `user` TEXT, `store` TEXT, `key` TEXT, `type` TEXT, `value` TEXT);";
-	if params.driver == "PostgreSQL" then
-		create_sql = create_sql:gsub("`", "\"");
-	elseif params.driver == "MySQL" then
-		create_sql = create_sql:gsub("`value` TEXT", "`value` MEDIUMTEXT");
-	end
-
-	local stmt, err = connection:prepare(create_sql);
-	if stmt then
-		local ok = stmt:execute();
-		local commit_ok = connection:commit();
-		if ok and commit_ok then
-			module:log("info", "Initialized new %s database with prosody table", params.driver);
-			local index_sql = "CREATE INDEX `prosody_index` ON `prosody` (`host`, `user`, `store`, `key`)";
-			if params.driver == "PostgreSQL" then
-				index_sql = index_sql:gsub("`", "\"");
-			elseif params.driver == "MySQL" then
-				index_sql = index_sql:gsub("`([,)])", "`(20)%1");
-			end
-			local stmt, err = connection:prepare(index_sql);
-			local ok, commit_ok, commit_err;
-			if stmt then
-				ok, err = stmt:execute();
-				commit_ok, commit_err = connection:commit();
-			end
-			if not(ok and commit_ok) then
-				module:log("warn", "Failed to create index (%s), lookups may not be optimised", err or commit_err);
-			end
-		elseif params.driver == "MySQL" then  -- COMPAT: Upgrade tables from 0.8.0
-			-- Failed to create, but check existing MySQL table here
-			local stmt = connection:prepare("SHOW COLUMNS FROM prosody WHERE Field='value' and Type='text'");
-			local ok = stmt:execute();
-			local commit_ok = connection:commit();
-			if ok and commit_ok then
-				if stmt:rowcount() > 0 then
-					module:log("info", "Upgrading database schema...");
-					local stmt = connection:prepare("ALTER TABLE prosody MODIFY COLUMN `value` MEDIUMTEXT");
-					local ok, err = stmt:execute();
-					local commit_ok = connection:commit();
-					if ok and commit_ok then
-						module:log("info", "Database table automatically upgraded");
-					else
-						module:log("error", "Failed to upgrade database schema (%s), please see "
-							.."http://prosody.im/doc/mysql for help",
-							err or "unknown error");
-					end
-				end
-				repeat until not stmt:fetch();
-			end
-		end
-	elseif params.driver ~= "SQLite3" then -- SQLite normally fails to prepare for existing table
-		module:log("warn", "Prosody was not able to automatically check/create the database table (%s), "
-			.."see http://prosody.im/doc/modules/mod_storage_sql#table_management for help.",
-			err or "unknown error");
-	end
-end
-
-do -- process options to get a db connection
-	local ok;
-	prosody.unlock_globals();
-	ok, DBI = pcall(require, "DBI");
-	if not ok then
-		package.loaded["DBI"] = {};
-		module:log("error", "Failed to load the LuaDBI library for accessing SQL databases: %s", DBI);
-		module:log("error", "More information on installing LuaDBI can be found at http://prosody.im/doc/depends#luadbi");
-	end
-	prosody.lock_globals();
-	if not ok or not DBI.Connect then
-		return; -- Halt loading of this module
-	end
-
-	params = params or { driver = "SQLite3" };
-
-	if params.driver == "SQLite3" then
-		params.database = resolve_relative_path(prosody.paths.data or ".", params.database or "prosody.sqlite");
-	end
-
-	assert(params.driver and params.database, "Both the SQL driver and the database need to be specified");
-
-	dburi = db2uri(params);
-	connection = connections[dburi];
+local default_params = { driver = "SQLite3" };
 
-	assert(connect());
-
-	-- Automatically create table, ignore failure (table probably already exists)
-	create_table();
-end
+local engine;
 
 local function serialize(value)
 	local t = type(value);
 	if t == "string" or t == "boolean" or t == "number" then
 		return t, tostring(value);
+	elseif is_stanza(value) then
+		return "xml", tostring(value);
 	elseif t == "table" then
 		local value,err = json.encode(value);
 		if value then return "json", value; end
@@ -194,55 +46,21 @@ local function deserialize(t, value)
 	elseif t == "number" then return tonumber(value);
 	elseif t == "json" then
 		return json.decode(value);
+	elseif t == "xml" then
+		return xml_parse(value);
 	end
 end
 
-local function dosql(sql, ...)
-	if params.driver == "PostgreSQL" then
-		sql = sql:gsub("`", "\"");
-	end
-	-- do prepared statement stuff
-	local stmt, err = connection:prepare(sql);
-	if not stmt and not test_connection() then error("connection failed"); end
-	if not stmt then module:log("error", "QUERY FAILED: %s %s", err, debug.traceback()); return nil, err; end
-	-- run query
-	local ok, err = stmt:execute(...);
-	if not ok and not test_connection() then error("connection failed"); end
-	if not ok then return nil, err; end
-
-	return stmt;
-end
-local function getsql(sql, ...)
-	return dosql(sql, host or "", user or "", store or "", ...);
-end
-local function setsql(sql, ...)
-	local stmt, err = getsql(sql, ...);
-	if not stmt then return stmt, err; end
-	return stmt:affected();
-end
-local function transact(...)
-	-- ...
-end
-local function rollback(...)
-	if connection then connection:rollback(); end -- FIXME check for rollback error?
-	return ...;
-end
-local function commit(...)
-	local success,err = connection:commit();
-	if not success then return nil, "SQL commit failed: "..tostring(err); end
-	return ...;
-end
+local host = module.host;
+local user, store;
 
 local function keyval_store_get()
-	local stmt, err = getsql("SELECT * FROM `prosody` WHERE `host`=? AND `user`=? AND `store`=?");
-	if not stmt then return rollback(nil, err); end
-
 	local haveany;
 	local result = {};
-	for row in stmt:rows(true) do
+	for row in engine:select("SELECT `key`,`type`,`value` FROM `prosody` WHERE `host`=? AND `user`=? AND `store`=?", host, user or "", store) do
 		haveany = true;
-		local k = row.key;
-		local v = deserialize(row.type, row.value);
+		local k = row[1];
+		local v = deserialize(row[2], row[3]);
 		if k and v then
 			if k ~= "" then result[k] = v; elseif type(v) == "table" then
 				for a,b in pairs(v) do
@@ -251,164 +69,374 @@ local function keyval_store_get()
 			end
 		end
 	end
-	return commit(haveany and result or nil);
+	if haveany then
+		return result;
+	end
 end
 local function keyval_store_set(data)
-	local affected, err = setsql("DELETE FROM `prosody` WHERE `host`=? AND `user`=? AND `store`=?");
-	if not affected then return rollback(affected, err); end
+	engine:delete("DELETE FROM `prosody` WHERE `host`=? AND `user`=? AND `store`=?", host, user or "", store);
 
 	if data and next(data) ~= nil then
 		local extradata = {};
 		for key, value in pairs(data) do
 			if type(key) == "string" and key ~= "" then
 				local t, value = serialize(value);
-				if not t then return rollback(t, value); end
-				local ok, err = setsql("INSERT INTO `prosody` (`host`,`user`,`store`,`key`,`type`,`value`) VALUES (?,?,?,?,?,?)", key, t, value);
-				if not ok then return rollback(ok, err); end
+				assert(t, value);
+				engine:insert("INSERT INTO `prosody` (`host`,`user`,`store`,`key`,`type`,`value`) VALUES (?,?,?,?,?,?)", host, user or "", store, key, t, value);
 			else
 				extradata[key] = value;
 			end
 		end
 		if next(extradata) ~= nil then
 			local t, extradata = serialize(extradata);
-			if not t then return rollback(t, extradata); end
-			local ok, err = setsql("INSERT INTO `prosody` (`host`,`user`,`store`,`key`,`type`,`value`) VALUES (?,?,?,?,?,?)", "", t, extradata);
-			if not ok then return rollback(ok, err); end
+			assert(t, extradata);
+			engine:insert("INSERT INTO `prosody` (`host`,`user`,`store`,`key`,`type`,`value`) VALUES (?,?,?,?,?,?)", host, user or "", store, "", t, extradata);
 		end
 	end
-	return commit(true);
+	return true;
 end
 
+--- Key/value store API (default store type)
+
 local keyval_store = {};
 keyval_store.__index = keyval_store;
 function keyval_store:get(username)
-	user,store = username,self.store;
-	if not connection and not connect() then return nil, "Unable to connect to database"; end
-	local success, ret, err = xpcall(keyval_store_get, debug.traceback);
-	if not connection and connect() then
-		success, ret, err = xpcall(keyval_store_get, debug.traceback);
+	user, store = username, self.store;
+	local ok, result = engine:transaction(keyval_store_get);
+	if not ok then
+		module:log("error", "Unable to read from database %s store for %s: %s", store, username or "<host>", result);
+		return nil, result;
 	end
-	if success then return ret, err; else return rollback(nil, ret); end
+	return result;	
 end
 function keyval_store:set(username, data)
 	user,store = username,self.store;
-	if not connection and not connect() then return nil, "Unable to connect to database"; end
-	local success, ret, err = xpcall(function() return keyval_store_set(data); end, debug.traceback);
-	if not connection and connect() then
-		success, ret, err = xpcall(function() return keyval_store_set(data); end, debug.traceback);
-	end
-	if success then return ret, err; else return rollback(nil, ret); end
+	return engine:transaction(function()
+		return keyval_store_set(data);
+	end);
 end
 function keyval_store:users()
-	local stmt, err = dosql("SELECT DISTINCT `user` FROM `prosody` WHERE `host`=? AND `store`=?", host, self.store);
-	if not stmt then
-		return rollback(nil, err);
-	end
-	local next = stmt:rows();
-	return commit(function()
-		local row = next();
-		return row and row[1];
+	local ok, result = engine:transaction(function()
+		return engine:select("SELECT DISTINCT `user` FROM `prosody` WHERE `host`=? AND `store`=?", host, self.store);
 	end);
+	if not ok then return ok, result end
+	return iterator(result);
 end
 
-local function map_store_get(key)
-	local stmt, err = getsql("SELECT * FROM `prosody` WHERE `host`=? AND `user`=? AND `store`=? AND `key`=?", key or "");
-	if not stmt then return rollback(nil, err); end
+--- Archive store API
 
-	local haveany;
-	local result = {};
-	for row in stmt:rows(true) do
-		haveany = true;
-		local k = row.key;
-		local v = deserialize(row.type, row.value);
-		if k and v then
-			if k ~= "" then result[k] = v; elseif type(v) == "table" then
-				for a,b in pairs(v) do
-					result[a] = b;
-				end
-			end
-		end
+local archive_store = {}
+archive_store.caps = {
+	total = true;
+};
+archive_store.__index = archive_store
+function archive_store:append(username, key, value, when, with)
+	if type(when) ~= "number" then
+		when, with, value = value, when, with;
 	end
-	return commit(haveany and result[key] or nil);
+	local user,store = username,self.store;
+	return engine:transaction(function()
+		if key then
+			engine:delete("DELETE FROM `prosodyarchive` WHERE `host`=? AND `user`=? AND `store`=? AND `key`=?", host, user or "", store, key);
+		else
+			key = uuid.generate();
+		end
+		local t, value = serialize(value);
+		engine:insert("INSERT INTO `prosodyarchive` (`host`, `user`, `store`, `when`, `with`, `key`, `type`, `value`) VALUES (?,?,?,?,?,?,?,?)", host, user or "", store, when, with, key, t, value);
+		return key;
+	end);
 end
-local function map_store_set(key, data)
-	local affected, err = setsql("DELETE FROM `prosody` WHERE `host`=? AND `user`=? AND `store`=? AND `key`=?", key or "");
-	if not affected then return rollback(affected, err); end
 
-	if data and next(data) ~= nil then
-		if type(key) == "string" and key ~= "" then
-			local t, value = serialize(data);
-			if not t then return rollback(t, value); end
-			local ok, err = setsql("INSERT INTO `prosody` (`host`,`user`,`store`,`key`,`type`,`value`) VALUES (?,?,?,?,?,?)", key, t, value);
-			if not ok then return rollback(ok, err); end
+-- Helpers for building the WHERE clause
+local function archive_where(query, args, where)
+	-- Time range, inclusive
+	if query.start then
+		args[#args+1] = query.start
+		where[#where+1] = "`when` >= ?"
+	end
+
+	if query["end"] then
+		args[#args+1] = query["end"];
+		if query.start then
+			where[#where] = "`when` BETWEEN ? AND ?" -- is this inclusive?
 		else
-			-- TODO non-string keys
+			where[#where+1] = "`when` <= ?"
 		end
 	end
-	return commit(true);
-end
 
-local map_store = {};
-map_store.__index = map_store;
-function map_store:get(username, key)
-	user,store = username,self.store;
-	local success, ret, err = xpcall(function() return map_store_get(key); end, debug.traceback);
-	if success then return ret, err; else return rollback(nil, ret); end
+	-- Related name
+	if query.with then
+		where[#where+1] = "`with` = ?";
+		args[#args+1] = query.with
+	end
+
+	-- Unique id
+	if query.key then
+		where[#where+1] = "`key` = ?";
+		args[#args+1] = query.key
+	end
 end
-function map_store:set(username, key, data)
-	user,store = username,self.store;
-	local success, ret, err = xpcall(function() return map_store_set(key, data); end, debug.traceback);
-	if success then return ret, err; else return rollback(nil, ret); end
+local function archive_where_id_range(query, args, where)
+	local args_len = #args
+	-- Before or after specific item, exclusive
+	if query.after then  -- keys better be unique!
+		where[#where+1] = "`sort_id` > (SELECT `sort_id` FROM `prosodyarchive` WHERE `key` = ? AND `host` = ? AND `user` = ? AND `store` = ? LIMIT 1)"
+		args[args_len+1], args[args_len+2], args[args_len+3], args[args_len+4] = query.after, args[1], args[2], args[3];
+		args_len = args_len + 4
+	end
+	if query.before then
+		where[#where+1] = "`sort_id` < (SELECT `sort_id` FROM `prosodyarchive` WHERE `key` = ? AND `host` = ? AND `user` = ? AND `store` = ? LIMIT 1)"
+		args[args_len+1], args[args_len+2], args[args_len+3], args[args_len+4] = query.before, args[1], args[2], args[3];
+	end
 end
 
-local list_store = {};
-list_store.__index = list_store;
-function list_store:scan(username, from, to, jid, typ)
-	user,store = username,self.store;
+function archive_store:find(username, query)
+	query = query or {};
+	local user,store = username,self.store;
+	local total;
+	local ok, result = engine:transaction(function()
+		local sql_query = "SELECT `key`, `type`, `value`, `when`, `with` FROM `prosodyarchive` WHERE %s ORDER BY `sort_id` %s%s;";
+		local args = { host, user or "", store, };
+		local where = { "`host` = ?", "`user` = ?", "`store` = ?", };
+
+		archive_where(query, args, where);
+
+		-- Total matching
+		if query.total then
+			local stats = engine:select("SELECT COUNT(*) FROM `prosodyarchive` WHERE " .. t_concat(where, " AND "), unpack(args));
+			if stats then
+				local _total = stats()
+				total = _total and _total[1];
+			end
+			if query.limit == 0 then -- Skip the real query
+				return noop, total;
+			end
+		end
 
-	local cols = {"from", "to", "jid", "typ"};
-	local vals = { from ,  to ,  jid ,  typ };
-	local stmt, err;
-	local query = "SELECT * FROM `prosodyarchive` WHERE `host`=? AND `user`=? AND `store`=?";
+		archive_where_id_range(query, args, where);
 
-	query = query.." ORDER BY time";
-	--local stmt, err = getsql("SELECT * FROM `prosody` WHERE `host`=? AND `user`=? AND `store`=? AND `key`=?", key or "");
+		if query.limit then
+			args[#args+1] = query.limit;
+		end
 
-	return nil, "not-implemented"
+		sql_query = sql_query:format(t_concat(where, " AND "), query.reverse and "DESC" or "ASC", query.limit and " LIMIT ?" or "");
+		module:log("debug", sql_query);
+		return engine:select(sql_query, unpack(args));
+	end);
+	if not ok then return ok, result end
+	return function()
+		local row = result();
+		if row ~= nil then
+			return row[1], deserialize(row[2], row[3]), row[4], row[5];
+		end
+	end, total;
 end
 
+function archive_store:delete(username, query)
+	query = query or {};
+	local user,store = username,self.store;
+	return engine:transaction(function()
+		local sql_query = "DELETE FROM `prosodyarchive` WHERE %s;";
+		local args = { host, user or "", store, };
+		local where = { "`host` = ?", "`user` = ?", "`store` = ?", };
+		if user == true then
+			table.remove(args, 2);
+			table.remove(where, 2);
+		end
+		archive_where(query, args, where);
+		archive_where_id_range(query, args, where);
+		sql_query = sql_query:format(t_concat(where, " AND "));
+		module:log("debug", sql_query);
+		return engine:delete(sql_query, unpack(args));
+	end);
+end
+
+local stores = {
+	keyval = keyval_store;
+	archive = archive_store;
+};
+
+--- Implement storage driver API
+
+-- FIXME: Some of these operations need to operate on the archive store(s) too
+
 local driver = {};
 
 function driver:open(store, typ)
-	if typ and typ ~= "keyval" then
-		return nil, "unsupported-store";
+	local store_mt = stores[typ or "keyval"];
+	if store_mt then
+		return setmetatable({ store = store }, store_mt);
 	end
-	return setmetatable({ store = store }, keyval_store);
+	return nil, "unsupported-store";
 end
 
 function driver:stores(username)
-	local sql = "SELECT DISTINCT `store` FROM `prosody` WHERE `host`=? AND `user`" ..
+	local query = "SELECT DISTINCT `store` FROM `prosody` WHERE `host`=? AND `user`" ..
 		(username == true and "!=?" or "=?");
 	if username == true or not username then
 		username = "";
 	end
-	local stmt, err = dosql(sql, host, username);
-	if not stmt then
-		return rollback(nil, err);
-	end
-	local next = stmt:rows();
-	return commit(function()
-		local row = next();
-		return row and row[1];
+	local ok, result = engine:transaction(function()
+		return engine:select(query, host, username);
 	end);
+	if not ok then return ok, result end
+	return iterator(result);
 end
 
 function driver:purge(username)
-	local stmt, err = dosql("DELETE FROM `prosody` WHERE `host`=? AND `user`=?", host, username);
-	if not stmt then return rollback(stmt, err); end
-	local changed, err = stmt:affected();
-	if not changed then return rollback(changed, err); end
-	return commit(true, changed);
+	return engine:transaction(function()
+		local stmt,err = engine:delete("DELETE FROM `prosody` WHERE `host`=? AND `user`=?", host, username);
+		return true, err;
+	end);
 end
 
-module:provides("storage", driver);
+--- Initialization
+
+
+local function create_table(name)
+	local Table, Column, Index = sql.Table, sql.Column, sql.Index;
+
+	local ProsodyTable = Table {
+		name= name or "prosody";
+		Column { name="host", type="TEXT", nullable=false };
+		Column { name="user", type="TEXT", nullable=false };
+		Column { name="store", type="TEXT", nullable=false };
+		Column { name="key", type="TEXT", nullable=false };
+		Column { name="type", type="TEXT", nullable=false };
+		Column { name="value", type="MEDIUMTEXT", nullable=false };
+		Index { name="prosody_index", "host", "user", "store", "key" };
+	};
+	engine:transaction(function()
+		ProsodyTable:create(engine);
+	end);
+
+	local ProsodyArchiveTable = Table {
+		name="prosodyarchive";
+		Column { name="sort_id", type="INTEGER", primary_key=true, auto_increment=true };
+		Column { name="host", type="TEXT", nullable=false };
+		Column { name="user", type="TEXT", nullable=false };
+		Column { name="store", type="TEXT", nullable=false };
+		Column { name="key", type="TEXT", nullable=false }; -- item id
+		Column { name="when", type="INTEGER", nullable=false }; -- timestamp
+		Column { name="with", type="TEXT", nullable=false }; -- related id
+		Column { name="type", type="TEXT", nullable=false };
+		Column { name="value", type="MEDIUMTEXT", nullable=false };
+		Index { name="prosodyarchive_index", unique = true, "host", "user", "store", "key" };
+	};
+	engine:transaction(function()
+		ProsodyArchiveTable:create(engine);
+	end);
+end
+
+local function upgrade_table(params, apply_changes)
+	local changes = false;
+	if params.driver == "MySQL" then
+		local success,err = engine:transaction(function()
+			local result = engine:execute("SHOW COLUMNS FROM prosody WHERE Field='value' and Type='text'");
+			if result:rowcount() > 0 then
+				changes = true;
+				if apply_changes then
+					module:log("info", "Upgrading database schema...");
+					engine:execute("ALTER TABLE prosody MODIFY COLUMN `value` MEDIUMTEXT");
+					module:log("info", "Database table automatically upgraded");
+				end
+			end
+			return true;
+		end);
+		if not success then
+			module:log("error", "Failed to check/upgrade database schema (%s), please see "
+				.."http://prosody.im/doc/mysql for help",
+				err or "unknown error");
+			return false;
+		end
+
+		-- COMPAT w/pre-0.10: Upgrade table to UTF-8 if not already
+		local check_encoding_query = "SELECT `COLUMN_NAME`,`COLUMN_TYPE`,`TABLE_NAME` FROM `information_schema`.`columns` WHERE `TABLE_NAME` LIKE 'prosody%%' AND ( `CHARACTER_SET_NAME`!='%s' OR `COLLATION_NAME`!='%s_bin' );";
+		check_encoding_query = check_encoding_query:format(engine.charset, engine.charset);
+		success,err = engine:transaction(function()
+			local result = engine:execute(check_encoding_query);
+			local n_bad_columns = result:rowcount();
+			if n_bad_columns > 0 then
+				changes = true;
+				if apply_changes then
+					module:log("warn", "Found %d columns in prosody table requiring encoding change, updating now...", n_bad_columns);
+					local fix_column_query1 = "ALTER TABLE `%s` CHANGE `%s` `%s` BLOB;";
+					local fix_column_query2 = "ALTER TABLE `%s` CHANGE `%s` `%s` %s CHARACTER SET '%s' COLLATE '%s_bin';";
+					for row in result:rows() do
+						local column_name, column_type, table_name  = unpack(row);
+						module:log("debug", "Fixing column %s in table %s", column_name, table_name);
+						engine:execute(fix_column_query1:format(table_name, column_name, column_name));
+						engine:execute(fix_column_query2:format(table_name, column_name, column_name, column_type, engine.charset, engine.charset));
+					end
+					module:log("info", "Database encoding upgrade complete!");
+				end
+			end
+		end);
+		success,err = engine:transaction(function() return engine:execute(check_encoding_query); end);
+		if not success then
+			module:log("error", "Failed to check/upgrade database encoding: %s", err or "unknown error");
+			return false;
+		end
+	end
+	return changes;
+end
+
+local function normalize_params(params)
+	if params.driver == "SQLite3" then
+		params.database = resolve_relative_path(prosody.paths.data or ".", params.database or "prosody.sqlite");
+	end
+	assert(params.driver and params.database, "Configuration error: Both the SQL driver and the database need to be specified");
+	return params;
+end
+
+function module.load()
+	if prosody.prosodyctl then return; end
+	local params = normalize_params(module:get_option("sql", default_params));
+	engine = sql:create_engine(params, function (engine)
+		if module:get_option("sql_manage_tables", true) then
+			-- Automatically create table, ignore failure (table probably already exists)
+			-- FIXME: we should check in information_schema, etc.
+			create_table();
+			-- Check whether the table needs upgrading
+			if upgrade_table(params, false) then
+				module:log("error", "Old database format detected. Please run: prosodyctl mod_%s upgrade", module.name);
+				return false, "database upgrade needed";
+			end
+		end
+	end);
+
+	module:provides("storage", driver);
+end
+
+function module.command(arg)
+	local config = require "core.configmanager";
+	local prosodyctl = require "util.prosodyctl";
+	local command = table.remove(arg, 1);
+	if command == "upgrade" then
+		-- We need to find every unique dburi in the config
+		local uris = {};
+		for host in pairs(prosody.hosts) do
+			local params = config.get(host, "sql") or default_params;
+			uris[sql.db2uri(params)] = params;
+		end
+		print("We will check and upgrade the following databases:\n");
+		for _, params in pairs(uris) do
+			print("", "["..params.driver.."] "..params.database..(params.host and " on "..params.host or ""));
+		end
+		print("");
+		print("Ensure you have working backups of the above databases before continuing! ");
+		if not prosodyctl.show_yesno("Continue with the database upgrade? [yN]") then
+			print("Ok, no upgrade. But you do have backups, don't you? ...don't you?? :-)");
+			return;
+		end
+		-- Upgrade each one
+		for _, params in pairs(uris) do
+			print("Checking "..params.database.."...");
+			engine = sql:create_engine(params);
+			upgrade_table(params, true);
+		end
+		print("All done!");
+	else
+		print("Unknown command: "..command);
+	end
+end
diff --git a/plugins/mod_storage_sql1.lua b/plugins/mod_storage_sql1.lua
new file mode 100644
index 00000000..a5bb5bfa
--- /dev/null
+++ b/plugins/mod_storage_sql1.lua
@@ -0,0 +1,414 @@
+
+--[[
+
+DB Tables:
+	Prosody - key-value, map
+		| host | user | store | key | type | value |
+	ProsodyArchive - list
+		| host | user | store | key | time | stanzatype | jsonvalue |
+
+Mapping:
+	Roster - Prosody
+		| host | user | "roster" | "contactjid" | type | value |
+		| host | user | "roster" | NULL | "json" | roster[false] data |
+	Account - Prosody
+		| host | user | "accounts" | "username" | type | value |
+
+	Offline - ProsodyArchive
+		| host | user | "offline" | "contactjid" | time | "message" | json|XML |
+
+]]
+
+local type = type;
+local tostring = tostring;
+local tonumber = tonumber;
+local pairs = pairs;
+local next = next;
+local setmetatable = setmetatable;
+local xpcall = xpcall;
+local json = require "util.json";
+local build_url = require"socket.url".build;
+
+local DBI;
+local connection;
+local host,user,store = module.host;
+local params = module:get_option("sql");
+
+local dburi;
+local connections = module:shared "/*/sql/connection-cache";
+
+local function db2uri(params)
+	return build_url{
+		scheme = params.driver,
+		user = params.username,
+		password = params.password,
+		host = params.host,
+		port = params.port,
+		path = params.database,
+	};
+end
+
+
+local resolve_relative_path = require "util.paths".resolve_relative_path;
+
+local function test_connection()
+	if not connection then return nil; end
+	if connection:ping() then
+		return true;
+	else
+		module:log("debug", "Database connection closed");
+		connection = nil;
+		connections[dburi] = nil;
+	end
+end
+local function connect()
+	if not test_connection() then
+		prosody.unlock_globals();
+		local dbh, err = DBI.Connect(
+			params.driver, params.database,
+			params.username, params.password,
+			params.host, params.port
+		);
+		prosody.lock_globals();
+		if not dbh then
+			module:log("debug", "Database connection failed: %s", tostring(err));
+			return nil, err;
+		end
+		module:log("debug", "Successfully connected to database");
+		dbh:autocommit(false); -- don't commit automatically
+		connection = dbh;
+
+		connections[dburi] = dbh;
+	end
+	return connection;
+end
+
+local function create_table()
+	if not module:get_option("sql_manage_tables", true) then
+		return;
+	end
+	local create_sql = "CREATE TABLE `prosody` (`host` TEXT, `user` TEXT, `store` TEXT, `key` TEXT, `type` TEXT, `value` TEXT);";
+	if params.driver == "PostgreSQL" then
+		create_sql = create_sql:gsub("`", "\"");
+	elseif params.driver == "MySQL" then
+		create_sql = create_sql:gsub("`value` TEXT", "`value` MEDIUMTEXT");
+	end
+
+	local stmt, err = connection:prepare(create_sql);
+	if stmt then
+		local ok = stmt:execute();
+		local commit_ok = connection:commit();
+		if ok and commit_ok then
+			module:log("info", "Initialized new %s database with prosody table", params.driver);
+			local index_sql = "CREATE INDEX `prosody_index` ON `prosody` (`host`, `user`, `store`, `key`)";
+			if params.driver == "PostgreSQL" then
+				index_sql = index_sql:gsub("`", "\"");
+			elseif params.driver == "MySQL" then
+				index_sql = index_sql:gsub("`([,)])", "`(20)%1");
+			end
+			local stmt, err = connection:prepare(index_sql);
+			local ok, commit_ok, commit_err;
+			if stmt then
+				ok, err = stmt:execute();
+				commit_ok, commit_err = connection:commit();
+			end
+			if not(ok and commit_ok) then
+				module:log("warn", "Failed to create index (%s), lookups may not be optimised", err or commit_err);
+			end
+		elseif params.driver == "MySQL" then  -- COMPAT: Upgrade tables from 0.8.0
+			-- Failed to create, but check existing MySQL table here
+			local stmt = connection:prepare("SHOW COLUMNS FROM prosody WHERE Field='value' and Type='text'");
+			local ok = stmt:execute();
+			local commit_ok = connection:commit();
+			if ok and commit_ok then
+				if stmt:rowcount() > 0 then
+					module:log("info", "Upgrading database schema...");
+					local stmt = connection:prepare("ALTER TABLE prosody MODIFY COLUMN `value` MEDIUMTEXT");
+					local ok, err = stmt:execute();
+					local commit_ok = connection:commit();
+					if ok and commit_ok then
+						module:log("info", "Database table automatically upgraded");
+					else
+						module:log("error", "Failed to upgrade database schema (%s), please see "
+							.."http://prosody.im/doc/mysql for help",
+							err or "unknown error");
+					end
+				end
+				repeat until not stmt:fetch();
+			end
+		end
+	elseif params.driver ~= "SQLite3" then -- SQLite normally fails to prepare for existing table
+		module:log("warn", "Prosody was not able to automatically check/create the database table (%s), "
+			.."see http://prosody.im/doc/modules/mod_storage_sql#table_management for help.",
+			err or "unknown error");
+	end
+end
+
+do -- process options to get a db connection
+	local ok;
+	prosody.unlock_globals();
+	ok, DBI = pcall(require, "DBI");
+	if not ok then
+		package.loaded["DBI"] = {};
+		module:log("error", "Failed to load the LuaDBI library for accessing SQL databases: %s", DBI);
+		module:log("error", "More information on installing LuaDBI can be found at http://prosody.im/doc/depends#luadbi");
+	end
+	prosody.lock_globals();
+	if not ok or not DBI.Connect then
+		return; -- Halt loading of this module
+	end
+
+	params = params or { driver = "SQLite3" };
+
+	if params.driver == "SQLite3" then
+		params.database = resolve_relative_path(prosody.paths.data or ".", params.database or "prosody.sqlite");
+	end
+
+	assert(params.driver and params.database, "Both the SQL driver and the database need to be specified");
+
+	dburi = db2uri(params);
+	connection = connections[dburi];
+
+	assert(connect());
+
+	-- Automatically create table, ignore failure (table probably already exists)
+	create_table();
+end
+
+local function serialize(value)
+	local t = type(value);
+	if t == "string" or t == "boolean" or t == "number" then
+		return t, tostring(value);
+	elseif t == "table" then
+		local value,err = json.encode(value);
+		if value then return "json", value; end
+		return nil, err;
+	end
+	return nil, "Unhandled value type: "..t;
+end
+local function deserialize(t, value)
+	if t == "string" then return value;
+	elseif t == "boolean" then
+		if value == "true" then return true;
+		elseif value == "false" then return false; end
+	elseif t == "number" then return tonumber(value);
+	elseif t == "json" then
+		return json.decode(value);
+	end
+end
+
+local function dosql(sql, ...)
+	if params.driver == "PostgreSQL" then
+		sql = sql:gsub("`", "\"");
+	end
+	-- do prepared statement stuff
+	local stmt, err = connection:prepare(sql);
+	if not stmt and not test_connection() then error("connection failed"); end
+	if not stmt then module:log("error", "QUERY FAILED: %s %s", err, debug.traceback()); return nil, err; end
+	-- run query
+	local ok, err = stmt:execute(...);
+	if not ok and not test_connection() then error("connection failed"); end
+	if not ok then return nil, err; end
+
+	return stmt;
+end
+local function getsql(sql, ...)
+	return dosql(sql, host or "", user or "", store or "", ...);
+end
+local function setsql(sql, ...)
+	local stmt, err = getsql(sql, ...);
+	if not stmt then return stmt, err; end
+	return stmt:affected();
+end
+local function transact(...)
+	-- ...
+end
+local function rollback(...)
+	if connection then connection:rollback(); end -- FIXME check for rollback error?
+	return ...;
+end
+local function commit(...)
+	local success,err = connection:commit();
+	if not success then return nil, "SQL commit failed: "..tostring(err); end
+	return ...;
+end
+
+local function keyval_store_get()
+	local stmt, err = getsql("SELECT * FROM `prosody` WHERE `host`=? AND `user`=? AND `store`=?");
+	if not stmt then return rollback(nil, err); end
+
+	local haveany;
+	local result = {};
+	for row in stmt:rows(true) do
+		haveany = true;
+		local k = row.key;
+		local v = deserialize(row.type, row.value);
+		if k and v then
+			if k ~= "" then result[k] = v; elseif type(v) == "table" then
+				for a,b in pairs(v) do
+					result[a] = b;
+				end
+			end
+		end
+	end
+	return commit(haveany and result or nil);
+end
+local function keyval_store_set(data)
+	local affected, err = setsql("DELETE FROM `prosody` WHERE `host`=? AND `user`=? AND `store`=?");
+	if not affected then return rollback(affected, err); end
+
+	if data and next(data) ~= nil then
+		local extradata = {};
+		for key, value in pairs(data) do
+			if type(key) == "string" and key ~= "" then
+				local t, value = serialize(value);
+				if not t then return rollback(t, value); end
+				local ok, err = setsql("INSERT INTO `prosody` (`host`,`user`,`store`,`key`,`type`,`value`) VALUES (?,?,?,?,?,?)", key, t, value);
+				if not ok then return rollback(ok, err); end
+			else
+				extradata[key] = value;
+			end
+		end
+		if next(extradata) ~= nil then
+			local t, extradata = serialize(extradata);
+			if not t then return rollback(t, extradata); end
+			local ok, err = setsql("INSERT INTO `prosody` (`host`,`user`,`store`,`key`,`type`,`value`) VALUES (?,?,?,?,?,?)", "", t, extradata);
+			if not ok then return rollback(ok, err); end
+		end
+	end
+	return commit(true);
+end
+
+local keyval_store = {};
+keyval_store.__index = keyval_store;
+function keyval_store:get(username)
+	user,store = username,self.store;
+	if not connection and not connect() then return nil, "Unable to connect to database"; end
+	local success, ret, err = xpcall(keyval_store_get, debug.traceback);
+	if not connection and connect() then
+		success, ret, err = xpcall(keyval_store_get, debug.traceback);
+	end
+	if success then return ret, err; else return rollback(nil, ret); end
+end
+function keyval_store:set(username, data)
+	user,store = username,self.store;
+	if not connection and not connect() then return nil, "Unable to connect to database"; end
+	local success, ret, err = xpcall(function() return keyval_store_set(data); end, debug.traceback);
+	if not connection and connect() then
+		success, ret, err = xpcall(function() return keyval_store_set(data); end, debug.traceback);
+	end
+	if success then return ret, err; else return rollback(nil, ret); end
+end
+function keyval_store:users()
+	local stmt, err = dosql("SELECT DISTINCT `user` FROM `prosody` WHERE `host`=? AND `store`=?", host, self.store);
+	if not stmt then
+		return rollback(nil, err);
+	end
+	local next = stmt:rows();
+	return commit(function()
+		local row = next();
+		return row and row[1];
+	end);
+end
+
+local function map_store_get(key)
+	local stmt, err = getsql("SELECT * FROM `prosody` WHERE `host`=? AND `user`=? AND `store`=? AND `key`=?", key or "");
+	if not stmt then return rollback(nil, err); end
+
+	local haveany;
+	local result = {};
+	for row in stmt:rows(true) do
+		haveany = true;
+		local k = row.key;
+		local v = deserialize(row.type, row.value);
+		if k and v then
+			if k ~= "" then result[k] = v; elseif type(v) == "table" then
+				for a,b in pairs(v) do
+					result[a] = b;
+				end
+			end
+		end
+	end
+	return commit(haveany and result[key] or nil);
+end
+local function map_store_set(key, data)
+	local affected, err = setsql("DELETE FROM `prosody` WHERE `host`=? AND `user`=? AND `store`=? AND `key`=?", key or "");
+	if not affected then return rollback(affected, err); end
+
+	if data and next(data) ~= nil then
+		if type(key) == "string" and key ~= "" then
+			local t, value = serialize(data);
+			if not t then return rollback(t, value); end
+			local ok, err = setsql("INSERT INTO `prosody` (`host`,`user`,`store`,`key`,`type`,`value`) VALUES (?,?,?,?,?,?)", key, t, value);
+			if not ok then return rollback(ok, err); end
+		else
+			-- TODO non-string keys
+		end
+	end
+	return commit(true);
+end
+
+local map_store = {};
+map_store.__index = map_store;
+function map_store:get(username, key)
+	user,store = username,self.store;
+	local success, ret, err = xpcall(function() return map_store_get(key); end, debug.traceback);
+	if success then return ret, err; else return rollback(nil, ret); end
+end
+function map_store:set(username, key, data)
+	user,store = username,self.store;
+	local success, ret, err = xpcall(function() return map_store_set(key, data); end, debug.traceback);
+	if success then return ret, err; else return rollback(nil, ret); end
+end
+
+local list_store = {};
+list_store.__index = list_store;
+function list_store:scan(username, from, to, jid, typ)
+	user,store = username,self.store;
+
+	local cols = {"from", "to", "jid", "typ"};
+	local vals = { from ,  to ,  jid ,  typ };
+	local stmt, err;
+	local query = "SELECT * FROM `prosodyarchive` WHERE `host`=? AND `user`=? AND `store`=?";
+
+	query = query.." ORDER BY time";
+	--local stmt, err = getsql("SELECT * FROM `prosody` WHERE `host`=? AND `user`=? AND `store`=? AND `key`=?", key or "");
+
+	return nil, "not-implemented"
+end
+
+local driver = {};
+
+function driver:open(store, typ)
+	if typ and typ ~= "keyval" then
+		return nil, "unsupported-store";
+	end
+	return setmetatable({ store = store }, keyval_store);
+end
+
+function driver:stores(username)
+	local sql = "SELECT DISTINCT `store` FROM `prosody` WHERE `host`=? AND `user`" ..
+		(username == true and "!=?" or "=?");
+	if username == true or not username then
+		username = "";
+	end
+	local stmt, err = dosql(sql, host, username);
+	if not stmt then
+		return rollback(nil, err);
+	end
+	local next = stmt:rows();
+	return commit(function()
+		local row = next();
+		return row and row[1];
+	end);
+end
+
+function driver:purge(username)
+	local stmt, err = dosql("DELETE FROM `prosody` WHERE `host`=? AND `user`=?", host, username);
+	if not stmt then return rollback(stmt, err); end
+	local changed, err = stmt:affected();
+	if not changed then return rollback(changed, err); end
+	return commit(true, changed);
+end
+
+module:provides("storage", driver);
diff --git a/plugins/mod_storage_sql2.lua b/plugins/mod_storage_sql2.lua
deleted file mode 100644
index 7695e15d..00000000
--- a/plugins/mod_storage_sql2.lua
+++ /dev/null
@@ -1,442 +0,0 @@
-
-local json = require "util.json";
-local sql = require "util.sql";
-local xml_parse = require "util.xml".parse;
-local uuid = require "util.uuid";
-local resolve_relative_path = require "util.paths".resolve_relative_path;
-
-local stanza_mt = require"util.stanza".stanza_mt;
-local getmetatable = getmetatable;
-local t_concat = table.concat;
-local function is_stanza(x) return getmetatable(x) == stanza_mt; end
-
-local noop = function() end
-local unpack = unpack
-local function iterator(result)
-	return function(result_)
-		local row = result_();
-		if row ~= nil then
-			return unpack(row);
-		end
-	end, result, nil;
-end
-
-local default_params = { driver = "SQLite3" };
-
-local engine;
-
-local function serialize(value)
-	local t = type(value);
-	if t == "string" or t == "boolean" or t == "number" then
-		return t, tostring(value);
-	elseif is_stanza(value) then
-		return "xml", tostring(value);
-	elseif t == "table" then
-		local value,err = json.encode(value);
-		if value then return "json", value; end
-		return nil, err;
-	end
-	return nil, "Unhandled value type: "..t;
-end
-local function deserialize(t, value)
-	if t == "string" then return value;
-	elseif t == "boolean" then
-		if value == "true" then return true;
-		elseif value == "false" then return false; end
-	elseif t == "number" then return tonumber(value);
-	elseif t == "json" then
-		return json.decode(value);
-	elseif t == "xml" then
-		return xml_parse(value);
-	end
-end
-
-local host = module.host;
-local user, store;
-
-local function keyval_store_get()
-	local haveany;
-	local result = {};
-	for row in engine:select("SELECT `key`,`type`,`value` FROM `prosody` WHERE `host`=? AND `user`=? AND `store`=?", host, user or "", store) do
-		haveany = true;
-		local k = row[1];
-		local v = deserialize(row[2], row[3]);
-		if k and v then
-			if k ~= "" then result[k] = v; elseif type(v) == "table" then
-				for a,b in pairs(v) do
-					result[a] = b;
-				end
-			end
-		end
-	end
-	if haveany then
-		return result;
-	end
-end
-local function keyval_store_set(data)
-	engine:delete("DELETE FROM `prosody` WHERE `host`=? AND `user`=? AND `store`=?", host, user or "", store);
-
-	if data and next(data) ~= nil then
-		local extradata = {};
-		for key, value in pairs(data) do
-			if type(key) == "string" and key ~= "" then
-				local t, value = serialize(value);
-				assert(t, value);
-				engine:insert("INSERT INTO `prosody` (`host`,`user`,`store`,`key`,`type`,`value`) VALUES (?,?,?,?,?,?)", host, user or "", store, key, t, value);
-			else
-				extradata[key] = value;
-			end
-		end
-		if next(extradata) ~= nil then
-			local t, extradata = serialize(extradata);
-			assert(t, extradata);
-			engine:insert("INSERT INTO `prosody` (`host`,`user`,`store`,`key`,`type`,`value`) VALUES (?,?,?,?,?,?)", host, user or "", store, "", t, extradata);
-		end
-	end
-	return true;
-end
-
---- Key/value store API (default store type)
-
-local keyval_store = {};
-keyval_store.__index = keyval_store;
-function keyval_store:get(username)
-	user, store = username, self.store;
-	local ok, result = engine:transaction(keyval_store_get);
-	if not ok then
-		module:log("error", "Unable to read from database %s store for %s: %s", store, username or "<host>", result);
-		return nil, result;
-	end
-	return result;	
-end
-function keyval_store:set(username, data)
-	user,store = username,self.store;
-	return engine:transaction(function()
-		return keyval_store_set(data);
-	end);
-end
-function keyval_store:users()
-	local ok, result = engine:transaction(function()
-		return engine:select("SELECT DISTINCT `user` FROM `prosody` WHERE `host`=? AND `store`=?", host, self.store);
-	end);
-	if not ok then return ok, result end
-	return iterator(result);
-end
-
---- Archive store API
-
-local archive_store = {}
-archive_store.caps = {
-	total = true;
-};
-archive_store.__index = archive_store
-function archive_store:append(username, key, value, when, with)
-	if type(when) ~= "number" then
-		when, with, value = value, when, with;
-	end
-	local user,store = username,self.store;
-	return engine:transaction(function()
-		if key then
-			engine:delete("DELETE FROM `prosodyarchive` WHERE `host`=? AND `user`=? AND `store`=? AND `key`=?", host, user or "", store, key);
-		else
-			key = uuid.generate();
-		end
-		local t, value = serialize(value);
-		engine:insert("INSERT INTO `prosodyarchive` (`host`, `user`, `store`, `when`, `with`, `key`, `type`, `value`) VALUES (?,?,?,?,?,?,?,?)", host, user or "", store, when, with, key, t, value);
-		return key;
-	end);
-end
-
--- Helpers for building the WHERE clause
-local function archive_where(query, args, where)
-	-- Time range, inclusive
-	if query.start then
-		args[#args+1] = query.start
-		where[#where+1] = "`when` >= ?"
-	end
-
-	if query["end"] then
-		args[#args+1] = query["end"];
-		if query.start then
-			where[#where] = "`when` BETWEEN ? AND ?" -- is this inclusive?
-		else
-			where[#where+1] = "`when` <= ?"
-		end
-	end
-
-	-- Related name
-	if query.with then
-		where[#where+1] = "`with` = ?";
-		args[#args+1] = query.with
-	end
-
-	-- Unique id
-	if query.key then
-		where[#where+1] = "`key` = ?";
-		args[#args+1] = query.key
-	end
-end
-local function archive_where_id_range(query, args, where)
-	local args_len = #args
-	-- Before or after specific item, exclusive
-	if query.after then  -- keys better be unique!
-		where[#where+1] = "`sort_id` > (SELECT `sort_id` FROM `prosodyarchive` WHERE `key` = ? AND `host` = ? AND `user` = ? AND `store` = ? LIMIT 1)"
-		args[args_len+1], args[args_len+2], args[args_len+3], args[args_len+4] = query.after, args[1], args[2], args[3];
-		args_len = args_len + 4
-	end
-	if query.before then
-		where[#where+1] = "`sort_id` < (SELECT `sort_id` FROM `prosodyarchive` WHERE `key` = ? AND `host` = ? AND `user` = ? AND `store` = ? LIMIT 1)"
-		args[args_len+1], args[args_len+2], args[args_len+3], args[args_len+4] = query.before, args[1], args[2], args[3];
-	end
-end
-
-function archive_store:find(username, query)
-	query = query or {};
-	local user,store = username,self.store;
-	local total;
-	local ok, result = engine:transaction(function()
-		local sql_query = "SELECT `key`, `type`, `value`, `when`, `with` FROM `prosodyarchive` WHERE %s ORDER BY `sort_id` %s%s;";
-		local args = { host, user or "", store, };
-		local where = { "`host` = ?", "`user` = ?", "`store` = ?", };
-
-		archive_where(query, args, where);
-
-		-- Total matching
-		if query.total then
-			local stats = engine:select("SELECT COUNT(*) FROM `prosodyarchive` WHERE " .. t_concat(where, " AND "), unpack(args));
-			if stats then
-				local _total = stats()
-				total = _total and _total[1];
-			end
-			if query.limit == 0 then -- Skip the real query
-				return noop, total;
-			end
-		end
-
-		archive_where_id_range(query, args, where);
-
-		if query.limit then
-			args[#args+1] = query.limit;
-		end
-
-		sql_query = sql_query:format(t_concat(where, " AND "), query.reverse and "DESC" or "ASC", query.limit and " LIMIT ?" or "");
-		module:log("debug", sql_query);
-		return engine:select(sql_query, unpack(args));
-	end);
-	if not ok then return ok, result end
-	return function()
-		local row = result();
-		if row ~= nil then
-			return row[1], deserialize(row[2], row[3]), row[4], row[5];
-		end
-	end, total;
-end
-
-function archive_store:delete(username, query)
-	query = query or {};
-	local user,store = username,self.store;
-	return engine:transaction(function()
-		local sql_query = "DELETE FROM `prosodyarchive` WHERE %s;";
-		local args = { host, user or "", store, };
-		local where = { "`host` = ?", "`user` = ?", "`store` = ?", };
-		if user == true then
-			table.remove(args, 2);
-			table.remove(where, 2);
-		end
-		archive_where(query, args, where);
-		archive_where_id_range(query, args, where);
-		sql_query = sql_query:format(t_concat(where, " AND "));
-		module:log("debug", sql_query);
-		return engine:delete(sql_query, unpack(args));
-	end);
-end
-
-local stores = {
-	keyval = keyval_store;
-	archive = archive_store;
-};
-
---- Implement storage driver API
-
--- FIXME: Some of these operations need to operate on the archive store(s) too
-
-local driver = {};
-
-function driver:open(store, typ)
-	local store_mt = stores[typ or "keyval"];
-	if store_mt then
-		return setmetatable({ store = store }, store_mt);
-	end
-	return nil, "unsupported-store";
-end
-
-function driver:stores(username)
-	local query = "SELECT DISTINCT `store` FROM `prosody` WHERE `host`=? AND `user`" ..
-		(username == true and "!=?" or "=?");
-	if username == true or not username then
-		username = "";
-	end
-	local ok, result = engine:transaction(function()
-		return engine:select(query, host, username);
-	end);
-	if not ok then return ok, result end
-	return iterator(result);
-end
-
-function driver:purge(username)
-	return engine:transaction(function()
-		local stmt,err = engine:delete("DELETE FROM `prosody` WHERE `host`=? AND `user`=?", host, username);
-		return true, err;
-	end);
-end
-
---- Initialization
-
-
-local function create_table(name)
-	local Table, Column, Index = sql.Table, sql.Column, sql.Index;
-
-	local ProsodyTable = Table {
-		name= name or "prosody";
-		Column { name="host", type="TEXT", nullable=false };
-		Column { name="user", type="TEXT", nullable=false };
-		Column { name="store", type="TEXT", nullable=false };
-		Column { name="key", type="TEXT", nullable=false };
-		Column { name="type", type="TEXT", nullable=false };
-		Column { name="value", type="MEDIUMTEXT", nullable=false };
-		Index { name="prosody_index", "host", "user", "store", "key" };
-	};
-	engine:transaction(function()
-		ProsodyTable:create(engine);
-	end);
-
-	local ProsodyArchiveTable = Table {
-		name="prosodyarchive";
-		Column { name="sort_id", type="INTEGER", primary_key=true, auto_increment=true };
-		Column { name="host", type="TEXT", nullable=false };
-		Column { name="user", type="TEXT", nullable=false };
-		Column { name="store", type="TEXT", nullable=false };
-		Column { name="key", type="TEXT", nullable=false }; -- item id
-		Column { name="when", type="INTEGER", nullable=false }; -- timestamp
-		Column { name="with", type="TEXT", nullable=false }; -- related id
-		Column { name="type", type="TEXT", nullable=false };
-		Column { name="value", type="MEDIUMTEXT", nullable=false };
-		Index { name="prosodyarchive_index", unique = true, "host", "user", "store", "key" };
-	};
-	engine:transaction(function()
-		ProsodyArchiveTable:create(engine);
-	end);
-end
-
-local function upgrade_table(params, apply_changes)
-	local changes = false;
-	if params.driver == "MySQL" then
-		local success,err = engine:transaction(function()
-			local result = engine:execute("SHOW COLUMNS FROM prosody WHERE Field='value' and Type='text'");
-			if result:rowcount() > 0 then
-				changes = true;
-				if apply_changes then
-					module:log("info", "Upgrading database schema...");
-					engine:execute("ALTER TABLE prosody MODIFY COLUMN `value` MEDIUMTEXT");
-					module:log("info", "Database table automatically upgraded");
-				end
-			end
-			return true;
-		end);
-		if not success then
-			module:log("error", "Failed to check/upgrade database schema (%s), please see "
-				.."http://prosody.im/doc/mysql for help",
-				err or "unknown error");
-			return false;
-		end
-
-		-- COMPAT w/pre-0.10: Upgrade table to UTF-8 if not already
-		local check_encoding_query = "SELECT `COLUMN_NAME`,`COLUMN_TYPE`,`TABLE_NAME` FROM `information_schema`.`columns` WHERE `TABLE_NAME` LIKE 'prosody%%' AND ( `CHARACTER_SET_NAME`!='%s' OR `COLLATION_NAME`!='%s_bin' );";
-		check_encoding_query = check_encoding_query:format(engine.charset, engine.charset);
-		success,err = engine:transaction(function()
-			local result = engine:execute(check_encoding_query);
-			local n_bad_columns = result:rowcount();
-			if n_bad_columns > 0 then
-				changes = true;
-				if apply_changes then
-					module:log("warn", "Found %d columns in prosody table requiring encoding change, updating now...", n_bad_columns);
-					local fix_column_query1 = "ALTER TABLE `%s` CHANGE `%s` `%s` BLOB;";
-					local fix_column_query2 = "ALTER TABLE `%s` CHANGE `%s` `%s` %s CHARACTER SET '%s' COLLATE '%s_bin';";
-					for row in result:rows() do
-						local column_name, column_type, table_name  = unpack(row);
-						module:log("debug", "Fixing column %s in table %s", column_name, table_name);
-						engine:execute(fix_column_query1:format(table_name, column_name, column_name));
-						engine:execute(fix_column_query2:format(table_name, column_name, column_name, column_type, engine.charset, engine.charset));
-					end
-					module:log("info", "Database encoding upgrade complete!");
-				end
-			end
-		end);
-		success,err = engine:transaction(function() return engine:execute(check_encoding_query); end);
-		if not success then
-			module:log("error", "Failed to check/upgrade database encoding: %s", err or "unknown error");
-			return false;
-		end
-	end
-	return changes;
-end
-
-local function normalize_params(params)
-	if params.driver == "SQLite3" then
-		params.database = resolve_relative_path(prosody.paths.data or ".", params.database or "prosody.sqlite");
-	end
-	assert(params.driver and params.database, "Configuration error: Both the SQL driver and the database need to be specified");
-	return params;
-end
-
-function module.load()
-	if prosody.prosodyctl then return; end
-	local params = normalize_params(module:get_option("sql", default_params));
-	engine = sql:create_engine(params, function (engine)
-		if module:get_option("sql_manage_tables", true) then
-			-- Automatically create table, ignore failure (table probably already exists)
-			-- FIXME: we should check in information_schema, etc.
-			create_table();
-			-- Check whether the table needs upgrading
-			if upgrade_table(params, false) then
-				module:log("error", "Old database format detected. Please run: prosodyctl mod_%s upgrade", module.name);
-				return false, "database upgrade needed";
-			end
-		end
-	end);
-
-	module:provides("storage", driver);
-end
-
-function module.command(arg)
-	local config = require "core.configmanager";
-	local prosodyctl = require "util.prosodyctl";
-	local command = table.remove(arg, 1);
-	if command == "upgrade" then
-		-- We need to find every unique dburi in the config
-		local uris = {};
-		for host in pairs(prosody.hosts) do
-			local params = config.get(host, "sql") or default_params;
-			uris[sql.db2uri(params)] = params;
-		end
-		print("We will check and upgrade the following databases:\n");
-		for _, params in pairs(uris) do
-			print("", "["..params.driver.."] "..params.database..(params.host and " on "..params.host or ""));
-		end
-		print("");
-		print("Ensure you have working backups of the above databases before continuing! ");
-		if not prosodyctl.show_yesno("Continue with the database upgrade? [yN]") then
-			print("Ok, no upgrade. But you do have backups, don't you? ...don't you?? :-)");
-			return;
-		end
-		-- Upgrade each one
-		for _, params in pairs(uris) do
-			print("Checking "..params.database.."...");
-			engine = sql:create_engine(params);
-			upgrade_table(params, true);
-		end
-		print("All done!");
-	else
-		print("Unknown command: "..command);
-	end
-end