Datastore Write Operations quota exhausted too quickly?

[Matt]

Hi there,

I'm currently running app engine under the free quota.

For some reason I'm exhausting my quota when I bulk delete from a table.

I've removing 3924 rows from a small table that has only five columns of string data. (Each only about 40 characters long maximum).

On the dashboard it's reporting:

Datastore Write Operations          0.05 of 0.05 Million Ops

Can you help me understand how I've managed to do accrue this many ops? I'm only running this single delete operation.

I've tried this over a series of days and each time I get the same result.

Thanks in advance,

Matt

[Simon Knott]

Hi,

Do you use any of the entity's properties in custom indexes at all?  It's pretty easy to blow the daily quota if you have all properties indexed and also use custom indexes.

From https://developers.google.com/appengine/docs/billing you can see that each delete consumes:

2 Writes + 2 Writes per indexed property value + 1 Write per composite index value

Even without custom indexes it will take 47088 writes to delete your entities, assuming you haven't turned off the per-property indexes, which is already pretty close to the quota.

Cheers,

Simon

[Matt]

Hey Simon,

Thanks for the fast response! That makes complete sense now. 

Thanks again,

Matt