How to Reduce Buffer Size for sys.stdin?

How to Reduce Buffer Size for sys.stdin

When executing the command:

<code class="bash">memcached -vv 2>&1 | tee memkeywatch2010098.log 2>&1 | ~/bin/memtracer.py | tee memkeywatchCounts20100908.log</code>

it was observed that memtracer.py does not start receiving input until memkeywatchYMD.log exceeds 15-18K in size. To address this, there are two approaches:

Using the unbuffered flag (-u)

Python provides an unbuffered flag -u that removes buffering from stdin/stdout. By calling Python with this flag:

<code class="bash">python -u ~/bin/memtracer.py</code>

you can completely eliminate buffering for stdin and stdout.

Creating a new file object with different buffering

You can also create a new file object with the same underlying file descriptor as standard input but with a smaller buffer size. This can be achieved using os.fdopen:

<code class="python">import os
import sys

# Create a new file object with a buffer size of 100 bytes
newin = os.fdopen(sys.stdin.fileno(), 'r', 100)

# Assign the new file object to standard input
sys.stdin = newin</code>

This code should allow you to read from standard input with a buffer size of only 100 bytes, resulting in faster response times. Note that this approach may have platform-specific limitations, so thorough testing is recommended.

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