fix master data sync performance issue
diff --git a/erpnext/accounts/doctype/sales_invoice/pos.py b/erpnext/accounts/doctype/sales_invoice/pos.py
index 11c68a3..e5c86dc 100644
--- a/erpnext/accounts/doctype/sales_invoice/pos.py
+++ b/erpnext/accounts/doctype/sales_invoice/pos.py
@@ -30,10 +30,16 @@
 	return {
 		'doc': doc,
 		'default_customer': pos_profile.get('customer'),
-		'items': get_items(doc, pos_profile),
+		'items': get_items_list(pos_profile),
 		'customers': get_customers_list(pos_profile),
-		'pricing_rules': get_pricing_rules(doc),
+		'serial_no_data': get_serial_no_data(pos_profile, doc.company),
+		'batch_no_data': get_batch_no_data(),
+		'tax_data': get_item_tax_data(),
+		'price_list_data': get_price_list_data(doc.selling_price_list),
+		'bin_data': get_bin_data(pos_profile),
+		'pricing_rules': get_pricing_rule_data(doc),
 		'print_template': print_template,
+		'pos_profile': pos_profile,
 		'meta': {
 			'invoice': frappe.get_meta('Sales Invoice'),
 			'items': frappe.get_meta('Sales Invoice Item'),
@@ -104,31 +110,6 @@
 	for tax in taxes:
 		doc.append('taxes', tax)
 
-def get_items(doc, pos_profile):
-	item_list = []
-	for item in get_items_list(pos_profile):
-		item_doc = frappe.get_doc('Item', item.name)
-		if item_doc.taxes:
-			item.taxes = json.dumps(dict(([d.tax_type, d.tax_rate] for d in
-						item_doc.get("taxes"))))
-
-		item.price_list_rate = frappe.db.get_value('Item Price', {'item_code': item.name,
-									'price_list': doc.selling_price_list}, 'price_list_rate') or 0
-		item.default_warehouse = pos_profile.get('warehouse') or \
-			get_item_warehouse_for_company(doc.company, item.default_warehouse) or None
-		item.expense_account = pos_profile.get('expense_account') or item.expense_account
-		item.income_account = pos_profile.get('income_account') or item_doc.income_account
-		item.cost_center = pos_profile.get('cost_center') or item_doc.selling_cost_center
-		item.actual_qty = frappe.db.get_value('Bin', {'item_code': item.name,
-								'warehouse': item.default_warehouse}, 'actual_qty') or 0
-		item.serial_nos = get_serial_nos(item, pos_profile, doc.company)
-		item.batch_nos = frappe.db.sql_list("""select name from `tabBatch` where ifnull(expiry_date, '4000-10-10') > curdate()
-			and item = %(item_code)s""", {'item_code': item.item_code})
-
-		item_list.append(item)
-
-	return item_list
-
 def get_items_list(pos_profile):
 	cond = "1=1"
 	item_groups = []
@@ -138,8 +119,15 @@
 		cond = "item_group in (%s)"%(', '.join(['%s']*len(pos_profile.get('item_groups'))))
 		item_groups = [d.item_group for d in pos_profile.get('item_groups')]
 
-	return frappe.db.sql(""" select * from tabItem where disabled = 0 and has_variants = 0 
-		and is_sales_item = 1 and {cond}""".format(cond=cond), tuple(item_groups), as_dict=1) or []
+	return frappe.db.sql(""" 
+		select
+			name, item_code, item_name, description, item_group, expense_account, has_batch_no,
+			has_serial_no, expense_account, selling_cost_center, stock_uom, image, default_warehouse
+		from
+			tabItem
+		where
+			disabled = 0 and has_variants = 0 and is_sales_item = 1 and {cond}
+		""".format(cond=cond), tuple(item_groups), as_dict=1)
 
 def get_customers_list(pos_profile):
 	cond = "1=1"
@@ -150,30 +138,88 @@
 		cond = "customer_group in (%s)"%(', '.join(['%s']*len(pos_profile.get('customer_groups'))))
 		customer_groups = [d.customer_group for d in pos_profile.get('customer_groups')]
 
-	return frappe.db.sql(""" select * from tabCustomer where disabled = 0 
+	return frappe.db.sql(""" select name, customer_name, customer_group,
+		territory from tabCustomer where disabled = 0
 		and {cond}""".format(cond=cond), tuple(customer_groups), as_dict=1) or {}
 
-def get_item_warehouse_for_company(company, warehouse):
-	if frappe.db.get_value('Warehouse', warehouse, 'company') != company:
-		warehouse = None
-	return warehouse
+def get_serial_no_data(pos_profile, company):
+	# get itemwise serial no data
+	# example {'Nokia Lumia 1020': {'SN0001': 'Pune'}}
+	# where Nokia Lumia 1020 is item code, SN0001 is serial no and Pune is warehouse
 
-def get_serial_nos(item, pos_profile, company):
 	cond = "1=1"
 	if pos_profile.get('update_stock') and pos_profile.get('warehouse'):
 		cond = "warehouse = '{0}'".format(pos_profile.get('warehouse'))
 
-	serial_nos = frappe.db.sql("""select name, warehouse from `tabSerial No` where {0}
-				and item_code = %(item_code)s and company = %(company)s
-				""".format(cond), {'item_code': item.item_code, 'company': company}, as_dict=1)
+	serial_nos = frappe.db.sql("""select name, warehouse, item_code from `tabSerial No` where {0}
+				and company = %(company)s """.format(cond), {'company': company}, as_dict=1)
 
-	serial_no_list = {}
-	for serial_no in serial_nos:
-		serial_no_list[serial_no.name] = serial_no.warehouse
+	itemwise_serial_no = {}
+	for sn in serial_nos:
+		if sn.item_code not in itemwise_serial_no:
+			itemwise_serial_no.setdefault(sn.item_code, {})
+		itemwise_serial_no[sn.item_code][sn.name] = sn.warehouse
 
-	return serial_no_list
+	return itemwise_serial_no
 
-def get_pricing_rules(doc):
+def get_batch_no_data():
+	# get itemwise batch no data
+	# exmaple: {'LED-GRE': [Batch001, Batch002]}
+	# where LED-GRE is item code, SN0001 is serial no and Pune is warehouse
+
+	itemwise_batch = {}
+	batches = frappe.db.sql("""select name, item from `tabBatch`
+		where ifnull(expiry_date, '4000-10-10') >= curdate()""", as_dict=1)
+
+	for batch in batches:
+		if batch.item not in itemwise_batch:
+			itemwise_batch.setdefault(batch.item, [])
+		itemwise_batch[batch.item].append(batch.name)
+
+	return itemwise_batch
+
+def get_item_tax_data():
+	# get default tax of an item
+	# example: {'Consulting Services': {'Excise 12 - TS': '12.000'}}
+
+	itemwise_tax = {}
+	taxes = frappe.db.sql(""" select parent, tax_type, tax_rate from `tabItem Tax`""", as_dict=1)
+
+	for tax in taxes:
+		if tax.parent not in itemwise_tax:
+			itemwise_tax.setdefault(tax.parent, {})
+		itemwise_tax[tax.parent][tax.tax_type] = tax.tax_rate
+
+	return itemwise_tax
+
+def get_price_list_data(selling_price_list):
+	itemwise_price_list = {}
+	price_lists = frappe.db.sql("""Select ifnull(price_list_rate, 0) as price_list_rate,
+		item_code from `tabItem Price` ip where price_list = %(price_list)s""",
+		{'price_list': selling_price_list}, as_dict=1)
+
+	for item in price_lists:
+		itemwise_price_list[item.item_code] = item.price_list_rate
+
+	return itemwise_price_list
+
+def get_bin_data(pos_profile):
+	itemwise_bin_data = {}
+	cond = "1=1"
+	if pos_profile.get('warehouse'):
+		cond = "warehouse = '{0}'".format(pos_profile.get('warehouse'))
+
+	bin_data = frappe.db.sql(""" select item_code, warehouse, actual_qty from `tabBin`
+		where actual_qty > 0 and {cond}""".format(cond=cond), as_dict=1)
+
+	for bins in bin_data:
+		if bins.item_code not in itemwise_bin_data:
+			itemwise_bin_data.setdefault(bins.item_code, {})
+		itemwise_bin_data[bins.item_code][bins.warehouse] = bins.actual_qty
+
+	return itemwise_bin_data
+
+def get_pricing_rule_data(doc):
 	pricing_rules = ""
 	if doc.ignore_pricing_rule == 0:
 		pricing_rules = frappe.db.sql(""" Select * from `tabPricing Rule` where docstatus < 2
diff --git a/erpnext/accounts/page/pos/pos.js b/erpnext/accounts/page/pos/pos.js
index cfc9582..26bf3ea 100644
--- a/erpnext/accounts/page/pos/pos.js
+++ b/erpnext/accounts/page/pos/pos.js
@@ -25,7 +25,6 @@
 		this.set_indicator();
 		this.onload();
 		this.make_menu_list();
-		this.set_interval_for_si_sync();
 		this.si_docs = this.get_doc_from_localstorage();
 	},
 
@@ -73,8 +72,6 @@
 		this.get_data_from_server(function(){
 			me.create_new();
 		});
-
-		this.check_internet_connection();
 	},
 
 	make_menu_list: function(){
@@ -204,13 +201,10 @@
 			freeze: true,
 			freeze_message: __("Master data syncing, it might take some time"),
 			callback: function(r){
-				window.items = r.message.items;
-				window.customers = r.message.customers;
-				window.pricing_rules = r.message.pricing_rules;
-				window.meta = r.message.meta;
-				window.print_template = r.message.print_template;
-				me.default_customer = r.message.default_customer || null;
+				me.init_master_data(r)
 				localStorage.setItem('doc', JSON.stringify(r.message.doc));
+				me.set_interval_for_si_sync();
+				me.check_internet_connection();
 				if(callback){
 					callback();
 				}
@@ -218,6 +212,22 @@
 		})
 	},
 
+	init_master_data: function(r){
+		var me = this;
+		this.meta = r.message.meta;
+		this.item_data = r.message.items;
+		this.customers = r.message.customers;
+		this.serial_no_data = r.message.serial_no_data;
+		this.batch_no_data = r.message.batch_no_data;
+		this.tax_data = r.message.tax_data;
+		this.price_list_data = r.message.price_list_data;
+		this.bin_data = r.message.bin_data;
+		this.pricing_rules = r.message.pricing_rules;
+		this.print_template = r.message.print_template;
+		this.pos_profile_data = r.message.pos_profile;
+		this.default_customer = r.message.default_customer || null;
+	},
+
 	save_previous_entry : function(){
 		if(this.frm.doc.items.length > 0){
 			this.create_invoice()
@@ -233,20 +243,19 @@
 	},
 
 	load_data: function(load_doc){
-		this.items = window.items;
-		this.customers = window.customers;
-		this.pricing_rules = window.pricing_rules;
+		var me = this;
 
+		this.items = this.item_data;
 		if(load_doc) {
 			this.frm.doc =  JSON.parse(localStorage.getItem('doc'));
 		}
 
-		$.each(window.meta, function(i, data){
+		$.each(this.meta, function(i, data){
 			frappe.meta.sync(data)
 		})
 
 		this.print_template = frappe.render_template("print_template",
-			{content: window.print_template, title:"POS",
+			{content: this.print_template, title:"POS",
 			base_url: frappe.urllib.get_base_url(), print_css: frappe.boot.print_css})
 	},
 
@@ -392,7 +401,7 @@
 				if(index < 30){
 					$(frappe.render_template("pos_item", {
 						item_code: obj.name,
-						item_price: format_currency(obj.price_list_rate, me.frm.doc.currency),
+						item_price: format_currency(me.price_list_data[obj.name], me.frm.doc.currency),
 						item_name: obj.name===obj.item_name ? "" : obj.item_name,
 						item_image: obj.image ? "url('" + obj.image + "')" : null,
 						color: frappe.get_palette(obj.item_name),
@@ -428,7 +437,7 @@
 		this.item_batch_no = {};
 
 		if(item_code){
-			return $.grep(window.items, function(item){
+			return $.grep(this.item_data, function(item){
 				if(item.item_code == item_code ){
 					return true
 				}
@@ -441,14 +450,15 @@
 		search_status = true
 
 		if(key){
-			return $.grep(window.items, function(item){
+			return $.grep(this.item_data, function(item){
 				if(search_status){
-					if(in_list(item.batch_nos, me.search.$input.val())){
+					if(in_list(me.batch_no_data[item.item_code], me.search.$input.val())){
 						search_status = false;
 						return me.item_batch_no[item.item_code] = me.search.$input.val()
-					} else if(in_list(Object.keys(item.serial_nos), me.search.$input.val())) {
+					} else if( me.serial_no_data[item.item_code]
+						&& in_list(Object.keys(me.serial_no_data[item.item_code]), me.search.$input.val())) {
 						search_status = false;
-						me.item_serial_no[item.item_code] = [me.search.$input.val(), item.serial_nos[me.search.$input.val()]]
+						me.item_serial_no[item.item_code] = [me.search.$input.val(), me.serial_no_data[item.item_code][me.search.$input.val()]]
 						return true
 					} else if(item.barcode == me.search.$input.val()) {
 						search_status = false;
@@ -460,7 +470,7 @@
 				}
 			})
 		}else{
-			return window.items;
+			return this.item_data;
 		}
 	},
 
@@ -613,18 +623,18 @@
 		this.child.description = this.items[0].description;
 		this.child.qty = 1;
 		this.child.item_group = this.items[0].item_group;
-		this.child.cost_center = this.items[0].cost_center;
-		this.child.income_account = this.items[0].income_account;
+		this.child.cost_center = this.pos_profile_data['cost_center'] || this.items[0].cost_center;
+		this.child.income_account = this.pos_profile_data['income_account'] || this.items[0].income_account;
 		this.child.warehouse = (this.item_serial_no[this.child.item_code]
-			? this.item_serial_no[this.child.item_code][1] : this.items[0].default_warehouse);
-		this.child.price_list_rate = flt(this.items[0].price_list_rate, 9) / flt(this.frm.doc.conversion_rate, 9);
-		this.child.rate = flt(this.items[0].price_list_rate, 9) / flt(this.frm.doc.conversion_rate, 9);
-		this.child.actual_qty = this.items[0].actual_qty;
+			? this.item_serial_no[this.child.item_code][1] : (this.pos_profile_data['warehouse'] || this.items[0].default_warehouse) );
+		this.child.price_list_rate = flt(this.price_list_data[this.child.item_code], 9) / flt(this.frm.doc.conversion_rate, 9);
+		this.child.rate = flt(this.price_list_data[this.child.item_code], 9) / flt(this.frm.doc.conversion_rate, 9);
+		this.child.actual_qty = me.get_actual_qty(this.items[0]);
 		this.child.amount = flt(this.child.qty) * flt(this.child.rate);
 		this.child.batch_no = this.item_batch_no[this.child.item_code];
 		this.child.serial_no = (this.item_serial_no[this.child.item_code]
 			? this.item_serial_no[this.child.item_code][0] : '');
-		this.child.item_tax_rate = this.items[0].taxes;
+		this.child.item_tax_rate = JSON.stringify(this.tax_data[this.child.item_code]);
 	},
 
 	update_paid_amount_status: function(update_paid_amount){
@@ -670,7 +680,7 @@
 				item_code: d.item_code,
 				item_name: (d.item_name===d.item_code || !d.item_name) ? "" : ("<br>" + d.item_name),
 				qty: d.qty,
-				actual_qty: d.actual_qty,
+				actual_qty: me.actual_qty,
 				projected_qty: d.projected_qty,
 				rate: format_number(d.rate, me.frm.doc.currency),
 				amount: format_currency(d.amount, me.frm.doc.currency)
@@ -1066,8 +1076,18 @@
 	},
 
 	validate_warehouse: function(){
-		if(!this.items[0].default_warehouse){
+		if(!this.items[0].default_warehouse && !this.pos_profile_data['warehouse']){
 			frappe.throw(__("Default warehouse is required for selected item"))
 		}
+	},
+
+	get_actual_qty: function(item) {
+		this.actual_qty = 0.0;
+		var warehouse = this.pos_profile_data['warehouse'] || item.default_warehouse;
+		if(warehouse && this.bin_data[item.item_code]) {
+			this.actual_qty = this.bin_data[item.item_code][warehouse] || 0;
+		}
+
+		return this.actual_qty
 	}
 })
\ No newline at end of file