Skip to content

Instantly share code, notes, and snippets.

View dch's full-sized avatar
🛋️

Dave Cottlehuber dch

🛋️
207 followers · 0 following
View GitHub Profile
@jhs
jhs / discussion.md
Created January 8, 2012 04:08
Log the conflict winner comparison

Conflict winners are chosen dynamically, every time a request for the document arrives. The revision tree is sort of like a git repository: most updates are based on a parent update. In general, you have a tree of changes, but usually it works out to a linear linked list.

Anyway, the winner is the version with the longest revision history. (That is arbitrary but deterministic, so two couches with the same revision trees will pick the same winner.)

couch_doc:to_doc_info_path does the main job: converting the revision tree into an array of paths from root to leaf. It returns this array sorted, with the longest path first. The diff here will print a log message every time the comparison function is called by lists:sort().

The execution path basically goes:

  1. couch_http_db:db_doc_req()
  2. couch_db:open_doc()
@dch
dch / couchdb-ec2-install.sh
Created November 30, 2011 12:30 — forked from msmith/couchdb-ec2-install.sh
Set up CouchDB on EC2
#!/bin/bash
#
# This script installs and configures couchdb on a fresh Amazon Linux AMI instance.
#
# Must be run with root privileges
# Tested with Amazon Linux AMI release 2011.02.1.1 (ami-8c1fece5)
#
export BUILD_DIR="$PWD"
@dch
dch / couchdocs_refresh.md
Created November 22, 2011 14:04
CouchDB Doc Refresh

Hi devs,

Over the last two years we've discussed improving our documentation, website, and wiki. We have discussed several designs ad mortem[1]…[5], and while the wiki has evolved substantially, not much else has changed.

This proposal summarises a consensus direction, and puts forward an approach that should allow us to improve docs in incremental stages with the usual peer review process for the actual patches/changes.

@max-mapper
max-mapper / readme.md
Created September 28, 2011 02:01
SLEEP - syncable.org

Your API does REST, but can it SLEEP?

SLEEP (Syncable Lightweight Event Emitting Persistence) is an emerging standard for distributed data sync using HTTP and JSON. A generalized version of CouchDB's much lauded built-in replication, SLEEP extends the REST architecture to define a way in which databases can offer syncable JSON APIs that foster open data innovation by allowing developers to replicate entire databases over the net.

SLEEP comes from the Apache CouchDB project which is now widely known for it's multi-master streaming HTTP + JSON replication. This is possible in part because of the CouchDB _changes feed, which is a particular API that lets you see if there have been any changes made to the database since last time you synchronized. CouchDB can efficiently implement the _changes feed because of one subtle difference between it and most other databases: it stores a history of all changes that happen to the database, including deletes.

If you synchronize data from a remote source and then the

@lucasfais
lucasfais / gist:1207002
Created September 9, 2011 18:46
Sublime Text 2 - Useful Shortcuts

Sublime Text 2 – Useful Shortcuts (Mac OS X)

General

⌘T go to file
⌘⌃P go to project
⌘R go to methods
⌃G go to line
⌘KB toggle side bar
⌘⇧P command prompt
@fdmanana
fdmanana / gist:1199903
Created September 7, 2011 06:21
Erlang OTP R14B, Mac OS X Lion 64bits and XCode 4.1

Issue

On Mac OS X Lion (64bits at least), we get random "Bus error 10" (or "Segmentation fault: 11") crashes if init:restart/0 is called and the crypto application is loaded. Why? XCode 4.1 ships an OpenSSL version that deprecates many functions used by OTP's crypto NIF (lib/crypto/c_src/crypto.c).

Example:

$ erl
@msmith
msmith / couchdb-ec2-install.sh
Created August 25, 2011 17:26
Set up CouchDB on EC2
#!/bin/bash
#
# This script installs and configures couchdb on a fresh Amazon Linux AMI instance.
#
# Must be run with root privileges
# Tested with Amazon Linux AMI release 2011.02.1.1 (ami-8c1fece5)
#
export BUILD_DIR="$PWD"
@dch
dch / compact_data.erl
Created June 24, 2011 01:57
useful examples using hovercraft
-module(compact_data).
-author('[email protected]').
-export([test_id_btree/1, test_db/4, test_view/1, test_view/4]).
-include("couch_db.hrl").
-define(ADMIN_USER_CTX, {user_ctx, #user_ctx{roles=[<<"_admin">>]}}).
test_id_btree(N) ->
@jchris
jchris / index.html
Created April 27, 2011 16:54
jQuery CouchDB Hello World - to use this script, create the map view in futon and click Save As, then upload index.html as an attachment to _design document created with the view. browse to index.html to run the app.
<!DOCTYPE html>
<html>
<head><title>Tiny CouchApp</title></head>
<body>
<h1>Tiny CouchApp</h1>
<form id="new_message">
<label for="message">Message:</label>
<input type="text" name="message" value="">
<p><input type="submit" value="Save &rarr;"></p>
</form>
@fdmanana
fdmanana / gist:832610
Created February 17, 2011 20:27
The CouchDB replicator database

1. Introduction to the replicator database

A database where you PUT/POST documents to trigger replications and you DELETE to cancel ongoing replications. These documents have exactly the same content as the JSON objects we used to POST to /_replicate/ (fields "source", "target", "create_target", "continuous", "doc_ids", "filter", "query_params".

Replication documents can have a user defined "_id". Design documents (and _local documents) added to the replicator database are ignored.

The default name of this database is _replicator. The name can be changed in the .ini configuration, section [replicator], parameter db.

2. Basics