Paging triggered on hitting low water mark - what exactly is paging?


#1

Hello,

Referring to the foll. page:
https://docs.couchbase.com/server/5.5/understanding-couchbase/buckets-memory-and-storage/memory.html#memory__ejection

Ejection section states that “If data is continuously loaded into the bucket, its quantity eventually increases to the value indicated by the mem_low_wat watermark. At this point, paging is triggered, so that memory-availability is continuously optimized.”

What exactly is paging? Can somebody pls help understand?

On the same page, Expiry Pager section states: “Scans for items that have expired, and erases them from memory and disk; after which, a tombstone remains for a default period of 3 days.” Is this same as paging?

Thanks


#2

Hi @pccb,

Since your question was posted, that doc page has been updated (specifically that sentence that mentions “paging” - https://github.com/couchbase/docs-server/commit/7b54f3bfc1293bdb2df19ec36c508f0e2560b8d9#diff-476ee405efa9a08461645782db62e8d7).

You may want to take a look at the page again. In the meantime, I will contact the writer who made that change to see if there’s any more light that can be shed.


#3

Thanks Matthew. But I see that paging is removed. Meaning to say nothing happens when the low water mark is hit on the way up. Is that really so?