Let's say I have a table called :table, and a column called :col, and
I want to go through all the records in the table and set the :col
value to 0. I had been doing it like this:
(defn update-db! []
(doseq [entry (fetch :table)]
(update! :table entry (assoc entry :col 0))))
but the other day I noticed that this was mysteriously skipping over
certain records, and not everything was getting updated. So I
switched to this:
(defn update-db! []
(doseq [entry (doall (fetch :table))]
(update! :table entry (assoc entry :col 0))))
which worked just fine. I speculate that somehow the update process
screws with whatever iteration process that fetch uses to deliver the
records lazily. However, now my update process is limited by the
number of records I can hold in memory.
So, is there some sort of recipe for updating all records without
first loading them all into memory?
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