From 2194d81965776b5a0e73b882915c07e104da8791 Mon Sep 17 00:00:00 2001
From: Anthony Tuininga <anthony.tuininga@gmail.com>
Date: Mon, 2 Nov 2020 15:20:45 -0700
Subject: [PATCH] Added test cases for prefetch.

---
 test/Cursor.py  | 43 +++++++++++++++++++++++++++++++++++++++++++
 test/TestEnv.py | 29 +++++++++++++++++++++++++++++
 2 files changed, 72 insertions(+)

diff --git a/test/Cursor.py b/test/Cursor.py
index 2b32b04..7e871d3 100644
--- a/test/Cursor.py
+++ b/test/Cursor.py
@@ -750,5 +750,48 @@ class TestCase(TestEnv.BaseTestCase):
                 where rowid = :1""", [rowid])
         self.assertEqual("Row %s" % rows[-3], self.cursor.fetchone()[0])
 
+    def testPrefetchRows(self):
+        "test prefetch rows"
+        self.setUpRoundTripChecker()
+
+        # perform simple query and verify only one round trip is needed
+        with self.connection.cursor() as cursor:
+            cursor.execute("select sysdate from dual").fetchall()
+            self.assertRoundTrips(1)
+
+        # set prefetchrows to 1 and verify that two round trips are now needed
+        with self.connection.cursor() as cursor:
+            cursor.prefetchrows = 1
+            cursor.execute("select sysdate from dual").fetchall()
+            self.assertRoundTrips(2)
+
+        # simple DDL only requires a single round trip
+        with self.connection.cursor() as cursor:
+            cursor.execute("truncate table TestTempTable")
+            self.assertRoundTrips(1)
+
+        # array execution only requires a single round trip
+        numRows = 590
+        with self.connection.cursor() as cursor:
+            sql = "insert into TestTempTable (IntCol) values (:1)"
+            data = [(n + 1,) for n in range(numRows)]
+            cursor.executemany(sql, data)
+            self.assertRoundTrips(1)
+
+        # setting prefetch and array size to 1 requires a round-trip for each
+        # row
+        with self.connection.cursor() as cursor:
+            cursor.prefetchrows = 1
+            cursor.arraysize = 1
+            cursor.execute("select IntCol from TestTempTable").fetchall()
+            self.assertRoundTrips(numRows + 1)
+
+        # setting prefetch and array size to 300 requires 2 round-trips
+        with self.connection.cursor() as cursor:
+            cursor.prefetchrows = 300
+            cursor.arraysize = 300
+            cursor.execute("select IntCol from TestTempTable").fetchall()
+            self.assertRoundTrips(2)
+
 if __name__ == "__main__":
     TestEnv.RunTestCases()
diff --git a/test/TestEnv.py b/test/TestEnv.py
index d52a59d..8ba4560 100644
--- a/test/TestEnv.py
+++ b/test/TestEnv.py
@@ -163,8 +163,34 @@ def GetPool(user=None, password=None, **kwargs):
 def GetClientVersion():
     return cx_Oracle.clientversion()
 
+class RoundTripInfo:
+
+    def __init__(self, connection):
+        self.prevRoundTrips = 0
+        self.adminConn = cx_Oracle.connect(GetAdminConnectString())
+        with connection.cursor() as cursor:
+            cursor.execute("select sys_context('userenv', 'sid') from dual")
+            self.sid, = cursor.fetchone()
+        self.getRoundTrips()
+
+    def getRoundTrips(self):
+        with self.adminConn.cursor() as cursor:
+            cursor.execute("""
+                    select ss.value
+                    from v$sesstat ss, v$statname sn
+                    where ss.sid = :sid
+                      and ss.statistic# = sn.statistic#
+                      and sn.name like '%roundtrip%client%'""", sid=self.sid)
+            currentRoundTrips, = cursor.fetchone()
+            diffRoundTrips = currentRoundTrips - self.prevRoundTrips
+            self.prevRoundTrips = currentRoundTrips
+            return diffRoundTrips
+
 class BaseTestCase(unittest.TestCase):
 
+    def assertRoundTrips(self, n):
+        self.assertEqual(self.roundTripInfo.getRoundTrips(), n)
+
     def getSodaDatabase(self, minclient=(18, 3), minserver=(18, 0),
             message="not supported with this client/server combination"):
         client = cx_Oracle.clientversion()[:2]
@@ -191,6 +217,9 @@ class BaseTestCase(unittest.TestCase):
         self.connection = GetConnection()
         self.cursor = self.connection.cursor()
 
+    def setUpRoundTripChecker(self):
+        self.roundTripInfo = RoundTripInfo(self.connection)
+
     def tearDown(self):
         self.connection.close()
         del self.cursor