From b97cfed6d7678409019bdf02a48f3c8b8abdb770 Mon Sep 17 00:00:00 2001
From: Ankush Menat <ankush@frappe.io>
Date: Sat, 19 Mar 2022 20:46:53 +0530
Subject: [PATCH] perf: limit rows to 1 for get_value and exists

---
 frappe/database/database.py | 35 ++++++++++++++++++++---------------
 1 file changed, 20 insertions(+), 15 deletions(-)

diff --git a/frappe/database/database.py b/frappe/database/database.py
index a3476c9538..099c9f1fde 100644
--- a/frappe/database/database.py
+++ b/frappe/database/database.py
@@ -384,7 +384,7 @@ class Database(object):
 		"""
 
 		ret = self.get_values(doctype, filters, fieldname, ignore, as_dict, debug,
-			order_by, cache=cache, for_update=for_update, run=run, pluck=pluck, distinct=distinct)
+			order_by, cache=cache, for_update=for_update, run=run, pluck=pluck, distinct=distinct, limit=1)
 
 		if not run:
 			return ret
@@ -393,7 +393,7 @@ class Database(object):
 
 	def get_values(self, doctype, filters=None, fieldname="name", ignore=None, as_dict=False,
 		debug=False, order_by="KEEP_DEFAULT_ORDERING", update=None, cache=False, for_update=False,
-		run=True, pluck=False, distinct=False):
+		run=True, pluck=False, distinct=False, limit=None):
 		"""Returns multiple document properties.
 
 		:param doctype: DocType name.
@@ -423,14 +423,15 @@ class Database(object):
 
 		if isinstance(filters, list):
 			out = self._get_value_for_many_names(
-				doctype,
-				filters,
-				fieldname,
-				order_by,
+				doctype=doctype,
+				names=filters,
+				field=fieldname,
+				order_by=order_by,
 				debug=debug,
 				run=run,
 				pluck=pluck,
 				distinct=distinct,
+				limit=limit,
 			)
 
 		else:
@@ -444,17 +445,18 @@ class Database(object):
 					if order_by:
 						order_by = "modified" if order_by == "KEEP_DEFAULT_ORDERING" else order_by
 					out = self._get_values_from_table(
-						fields,
-						filters,
-						doctype,
-						as_dict,
-						debug,
-						order_by,
-						update,
+						fields=fields,
+						filters=filters,
+						doctype=doctype,
+						as_dict=as_dict,
+						debug=debug,
+						order_by=order_by,
+						update=update,
 						for_update=for_update,
 						run=run,
 						pluck=pluck,
-						distinct=distinct
+						distinct=distinct,
+						limit=limit,
 					)
 				except Exception as e:
 					if ignore and (frappe.db.is_missing_column(e) or frappe.db.is_table_missing(e)):
@@ -623,6 +625,7 @@ class Database(object):
 		run=True,
 		pluck=False,
 		distinct=False,
+		limit=None,
 	):
 		field_objects = []
 
@@ -641,6 +644,7 @@ class Database(object):
 			field_objects=field_objects,
 			fields=fields,
 			distinct=distinct,
+			limit=limit,
 		)
 		if (
 			fields == "*"
@@ -654,7 +658,7 @@ class Database(object):
 		)
 		return r
 
-	def _get_value_for_many_names(self, doctype, names, field, order_by, debug=False, run=True, pluck=False, distinct=False):
+	def _get_value_for_many_names(self, doctype, names, field, order_by, debug=False, run=True, pluck=False, distinct=False, limit=None):
 		names = list(filter(None, names))
 		if names:
 			return self.get_all(
@@ -667,6 +671,7 @@ class Database(object):
 				as_list=1,
 				run=run,
 				distinct=distinct,
+				limit_page_length=limit
 			)
 		else:
 			return {}