if (keys(%BigHash))

[download]
will be false iff the hash is empty. Assuming the hash won't be empty after it is loaded, that should do the job.

Update: moritz is right 

if (%BigHash) {

[download]
should do the same job.

In reply to Re: lazy creation of a hash by jpl
in thread lazy creation of a hash by John M. Dlugosz

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