Buffer Requests Trace

From: Lucas Lersch <lucaslersch(at)gmail(dot)com>
To: pgsql-hackers(at)postgresql(dot)org
Subject: Buffer Requests Trace
Date: 2014-10-14 16:08:31
Message-ID: CAGR3jZAy3ckTu48gp3CmeQ8riB10Mo+jHYy_XMLjwx=DsruTug@mail.gmail.com
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Hello,

I changed the buffer manager code in order to generate a trace of page
requests from the buffer manager perspective. In summary, whenever
ReleaseBuffer() or ReleaseAndReadBuffer() are called, I print the page
currently being released which is identified by the tuple (tableSpace,
dbNode, relationNode, blockNumber).

I am now running a tpcc benchmark from http://oltpbenchmark.com/

Initially I create and load the database with a scale factor of 64. This
sums up to a database of around 6.7GB (~ 800k pages). Then I execute the
tpcc benchmark for 1 minute with only 1 terminal. Finally I analyse the
trace of the buffer requests made by the execution of the benchmark only
(creation and loading not considered).

Unfortunately, in the generated trace with over 2 million buffer requests,
only ~14k different pages are being accessed, out of the 800k of the whole
database. Am I missing something here?

Best regards.
--
Lucas Lersch

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