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