Django database cache TIMEOUT - make backend delete row











up vote
2
down vote

favorite
2












I'm not sure what Django database cache does with expired entries but it seems that they remain in the database.



I want Django to delete them after they expire because their size is huge and there can be unlimited number of different keys.



CACHES = {
'default': {
'BACKEND': 'django.core.cache.backends.db.DatabaseCache',
'LOCATION': 'cache_table',
'TIMEOUT': 60 * 20,
}
}


I use cache on filtered list of objects and this filter contais number and char fields.



Is it possible?










share|improve this question


























    up vote
    2
    down vote

    favorite
    2












    I'm not sure what Django database cache does with expired entries but it seems that they remain in the database.



    I want Django to delete them after they expire because their size is huge and there can be unlimited number of different keys.



    CACHES = {
    'default': {
    'BACKEND': 'django.core.cache.backends.db.DatabaseCache',
    'LOCATION': 'cache_table',
    'TIMEOUT': 60 * 20,
    }
    }


    I use cache on filtered list of objects and this filter contais number and char fields.



    Is it possible?










    share|improve this question
























      up vote
      2
      down vote

      favorite
      2









      up vote
      2
      down vote

      favorite
      2






      2





      I'm not sure what Django database cache does with expired entries but it seems that they remain in the database.



      I want Django to delete them after they expire because their size is huge and there can be unlimited number of different keys.



      CACHES = {
      'default': {
      'BACKEND': 'django.core.cache.backends.db.DatabaseCache',
      'LOCATION': 'cache_table',
      'TIMEOUT': 60 * 20,
      }
      }


      I use cache on filtered list of objects and this filter contais number and char fields.



      Is it possible?










      share|improve this question













      I'm not sure what Django database cache does with expired entries but it seems that they remain in the database.



      I want Django to delete them after they expire because their size is huge and there can be unlimited number of different keys.



      CACHES = {
      'default': {
      'BACKEND': 'django.core.cache.backends.db.DatabaseCache',
      'LOCATION': 'cache_table',
      'TIMEOUT': 60 * 20,
      }
      }


      I use cache on filtered list of objects and this filter contais number and char fields.



      Is it possible?







      python django caching django-database django-cache






      share|improve this question













      share|improve this question











      share|improve this question




      share|improve this question










      asked Nov 11 at 21:52









      Milano

      4,1731140112




      4,1731140112
























          1 Answer
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          up vote
          1
          down vote













          It isn't possible to purge expired entries as they expire. This is one of the many reasons you probably don't want to use the database cache in production!



          If possible, you should switch to a different cache backend (I prefer Redis). If you can't, you do have a few other options:




          1. If you know the cache keys you want to purge, you can use the low-level cache API to directly delete the keys you want to purge.


          2. You could tweak the MAX_ENTRIES and/or CULL_FREQUENCY cache arguments to limit the overall size of the cache.


          3. You could poke into the database directly (perhaps from a background task or cron job), manually running some SQL like DELETE FROM cache_table WHERE expires < now() (I haven't tested this, but I think it should work).







          share|improve this answer





















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            1 Answer
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            1 Answer
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            active

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            active

            oldest

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            up vote
            1
            down vote













            It isn't possible to purge expired entries as they expire. This is one of the many reasons you probably don't want to use the database cache in production!



            If possible, you should switch to a different cache backend (I prefer Redis). If you can't, you do have a few other options:




            1. If you know the cache keys you want to purge, you can use the low-level cache API to directly delete the keys you want to purge.


            2. You could tweak the MAX_ENTRIES and/or CULL_FREQUENCY cache arguments to limit the overall size of the cache.


            3. You could poke into the database directly (perhaps from a background task or cron job), manually running some SQL like DELETE FROM cache_table WHERE expires < now() (I haven't tested this, but I think it should work).







            share|improve this answer

























              up vote
              1
              down vote













              It isn't possible to purge expired entries as they expire. This is one of the many reasons you probably don't want to use the database cache in production!



              If possible, you should switch to a different cache backend (I prefer Redis). If you can't, you do have a few other options:




              1. If you know the cache keys you want to purge, you can use the low-level cache API to directly delete the keys you want to purge.


              2. You could tweak the MAX_ENTRIES and/or CULL_FREQUENCY cache arguments to limit the overall size of the cache.


              3. You could poke into the database directly (perhaps from a background task or cron job), manually running some SQL like DELETE FROM cache_table WHERE expires < now() (I haven't tested this, but I think it should work).







              share|improve this answer























                up vote
                1
                down vote










                up vote
                1
                down vote









                It isn't possible to purge expired entries as they expire. This is one of the many reasons you probably don't want to use the database cache in production!



                If possible, you should switch to a different cache backend (I prefer Redis). If you can't, you do have a few other options:




                1. If you know the cache keys you want to purge, you can use the low-level cache API to directly delete the keys you want to purge.


                2. You could tweak the MAX_ENTRIES and/or CULL_FREQUENCY cache arguments to limit the overall size of the cache.


                3. You could poke into the database directly (perhaps from a background task or cron job), manually running some SQL like DELETE FROM cache_table WHERE expires < now() (I haven't tested this, but I think it should work).







                share|improve this answer












                It isn't possible to purge expired entries as they expire. This is one of the many reasons you probably don't want to use the database cache in production!



                If possible, you should switch to a different cache backend (I prefer Redis). If you can't, you do have a few other options:




                1. If you know the cache keys you want to purge, you can use the low-level cache API to directly delete the keys you want to purge.


                2. You could tweak the MAX_ENTRIES and/or CULL_FREQUENCY cache arguments to limit the overall size of the cache.


                3. You could poke into the database directly (perhaps from a background task or cron job), manually running some SQL like DELETE FROM cache_table WHERE expires < now() (I haven't tested this, but I think it should work).








                share|improve this answer












                share|improve this answer



                share|improve this answer










                answered Nov 11 at 22:25









                jacobian

                4,08021511




                4,08021511






























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