84 lines
2.3 KiB
Python
Executable File
84 lines
2.3 KiB
Python
Executable File
import time
|
|
import traceback
|
|
|
|
from django.db import transaction
|
|
from django.http import HttpResponse
|
|
|
|
from regluit.core.models import Campaign
|
|
|
|
def test_read(request):
|
|
|
|
try:
|
|
|
|
row_id = 1
|
|
|
|
print "Attempting to read row"
|
|
|
|
# A read the waits for the exclusive lock for the row
|
|
campaign = Campaign.objects.raw("SELECT * FROM core_campaign WHERE id=%d FOR UPDATE" % row_id)[0]
|
|
|
|
print "Successfully read row data %d" % campaign.target
|
|
|
|
except:
|
|
traceback.print_exc()
|
|
|
|
return HttpResponse("Success")
|
|
|
|
def test_write(request):
|
|
|
|
try:
|
|
|
|
row_id = 1
|
|
campaign = Campaign.objects.get(id=row_id)
|
|
|
|
print "Attempting to write row via ordinary ORM"
|
|
|
|
#
|
|
# Modify the data. This will block if any shared lock (Either FOR UPDATE or LOCK IN SHARED MODE is held
|
|
#
|
|
campaign.target = campaign.target + 10
|
|
campaign.save()
|
|
|
|
print "Successfully write new row data %d" % campaign.target
|
|
|
|
except:
|
|
traceback.print_exc()
|
|
|
|
return HttpResponse("Success")
|
|
|
|
@transaction.commit_on_success
|
|
def test_lock(request):
|
|
|
|
try:
|
|
row_id = 1
|
|
|
|
print "Attempting to acquire row lock"
|
|
|
|
campaign = Campaign.objects.raw("SELECT * FROM core_campaign WHERE id=%d FOR UPDATE" % row_id)[0]
|
|
|
|
print "Row lock acquired, modifying data"
|
|
|
|
# Modify the data
|
|
campaign.target = campaign.target + 10
|
|
campaign.save()
|
|
|
|
#
|
|
# test by sleeping here for 10 seconds.
|
|
#
|
|
# The FOR UPDATE request will lock the row exclusively. All write/delete operations require a compatible lock
|
|
# and will block until this transaction is complete. Some reads will block, but some will not. If we want to
|
|
# block the read until this transaction is complete, the read should also acquire an exlusive OR a shared lock.
|
|
#
|
|
# As soon as the function completes, the transaction will be committed and the lock released.
|
|
# You can modify the commit_on_success decorator to get different transaction behaviors
|
|
#
|
|
print "Thread sleeping for 10 seconds"
|
|
time.sleep(10)
|
|
print "Thread sleep complete"
|
|
|
|
except:
|
|
traceback.print_exc()
|
|
|
|
return HttpResponse("Success")
|
|
|