I have a datastore with around 1,000,000 entities in a model. I want to fetch 10 random entities from this.
I am not sure how to do this? can someone help?
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I have a datastore with around 1,000,000 entities in a model. I want to fetch 10 random entities from this.
I am not sure how to do this? can someone help?
Assign each entity a random number and store it in the entity. Then query for ten records whose random number is greater than (or less than) some other random number.
You’ll also need to sort on your random number column, otherwise, Google App Engine will pick 10 entries that are greater (or less than) your number, but it will pick them in a non random way. So, if you are picking records whose random number is greater than a random number, you’d sort asending on the column, otherwise you’d sort decending.
This isn’t totally random, however, since entities with nearby random numbers will tend to show up together. If you want to beat this, do ten queries based around ten random numbers, but this will be less efficient.