Nick Vatamaniuc nickva

Software Developer at IBM Cloudant focusing on distributed database systems and data replication. Some tools I like: Erlang/OTP, Python, C, Linux.

nickva / filebench.erl

Last active May 9, 2023 04:08

Silly benchmark reading a block in a loop and measuring the average across multiple runs


	%> filebench:all("...data.../filebench.couch").
	% * bsize: 65536 pread: 11 couch_file pread: 74 write: 465 couch_file append_bin: 477
	% * bsize: 16384 pread: 8 couch_file pread: 49 write: 218 couch_file append_bin: 277
	% * bsize: 4096 pread: 9 couch_file pread: 41 write: 197 couch_file append_bin: 236
	% * bsize: 1024 pread: 11 couch_file pread: 37 write: 183 couch_file append_bin: 222
	%

	-module(filebench).

nickva / distbench.erl

Last active September 7, 2023 15:30

Ping-pong across dist with N parallel workers

nickva / fixalloc.erl

Last active August 29, 2024 12:24

Erlang 24 and 25 fix_alloc memory leak

	%
	% Run on Erlang 24+
	%
	% (MFatags true is to enable instrumentation for fix_alloc)
	%
	% $ erl -name n1@127.0.0.1 +MFatags true
	% (n1@127.0.0.1)>
	%
	% $ erl -name n2@127.0.0.1 +MFatags true
	% (n2@127.0.0.1)2> c(fixalloc), fixalloc:go('n1@127.0.0.1').

nickva / quickjs_vs_sm91.md

Created February 27, 2023 19:58

Overhead comparison QuickJS vs Spidermonkey 91. Measure process startup and context init

Spidermonkey (91), QuickJS (2021-03-27)

Intel MacOS SM91

% ./configure --dev --spidermonkey-version 91 && make
% TIMEFMT=$'Total (sec): \t%*E\nMax RSS(kb): \t%M\n'
% time ./couchjs

nickva / xref_custom.erl

Created January 5, 2023 20:03

Run Erlang XRef Ignoring Some Modules

	xref:stop(s).
	xref:start(s).
	xref:set_default(s, [{verbose, false}, {warnings, false}]).
	xref:add_release(s, "./src").
	xref:add_release(s, code:lib_dir(), {name, otp}).

	f().

	IgnorePrefixes = [
	"hipe", "ibrowse", "hyper", "meck", "metrics", "parse_trans", "eunit_test", "hackney",

nickva / playing_around.erl

Created December 23, 2022 19:35

Luerl for CouchDB Views

	1> application:start(luerl),
	1> F1 = "function(doc) emit('key1', doc) \n emit('key2', 'val2') end",
	1> F2 = "function(doc) emit('key3', 'val3') end",
	1> S0 = luerl_sandbox:init(),
	1> {_, S1} = luerl:do("emits = {} \n function emit(k, v) \n table.insert(emits, {k, v}) end", S0),
	1> {ok, C1, S2} = luerl:load("f = " ++ F1 ++ " \n f(...) \n return emits", S1),
	1> {ok, C2, S3} = luerl:load("f = " ++ F2 ++ " \n f(...) \n return emits", S2),
	1> {R1, _} = luerl:call_chunk(C1, [#{<<"_id">> => <<"1">>, <<"a">> => <<"b">>}], S3),
	1> {R2, _} = luerl:call_chunk(C2, [#{<<"_id">> => <<"1">>, <<"a">> => <<"b">>}], S3),
	1> #{<<"r1">> => R1, <<"r2">> => R2}.

nickva / viewsize.py

Last active December 7, 2022 18:37

CouchDB View Benchmark

	#!/usr/bin/env python

	# still python2, sorry, old script
	# pip install CouchDB
	# ./viewsize.py
	# file active external dtavg
	# 18080120 17607050 14984706 45.973

	import argparse
	import sys

nickva / dbcreate.py

Created November 28, 2022 18:08

Apache CouchDB DB Stampede

	#!/usr/bin/env python

	# Uses CouchDB (pip install CouchDB)

	import sys, couchdb, time, os, uuid, argparse, random, traceback
	from multiprocessing.dummy import Pool as ThreadPool

	DB_URLS = [
	'http://adm:pass@localhost:15984',
	'http://adm:pass@localhost:25984',

nickva / large_doc_compact_multiple_updates.sh

Created November 13, 2022 04:00

CouchDB doc update and delete script

nickva / large_doc_compact.sh

Created November 11, 2022 20:04

couchdb smoosh doesn't trigger compaction