David Liman dvliman

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Spike

I looked into the state of GraalVM and Clojure and wrote some small work-related scripts.

GraalVM Build Tools

Downloaded GraalVM and set $GRAALVM_HOME
Found two main libraries for building GraalVM CLIs - https://github.com/luchiniatwork/cambada#packaging-as-a-native-image and https://github.com/taylorwood/clj.native-image (or https://github.com/taylorwood/lein-native-image for the lein equivalent). I chose clj.native-image as it seemed more focused on doing one thing well.
First tried its template example which was easy to follow.
Then added a graalvm build to one of our small cli tools
Found it to be pretty straightforward except for a stdout flushing issue that was trivial to fix

Turning PostgreSQL into a queue serving 10,000 jobs per second

RDBMS-based job queues have been criticized recently for being unable to handle heavy loads. And they deserve it, to some extent, because the queries used to safely lock a job have been pretty hairy. SELECT FOR UPDATE followed by an UPDATE works fine at first, but then you add more workers, and each is trying to SELECT FOR UPDATE the same row (and maybe throwing NOWAIT in there, then catching the errors and retrying), and things slow down.

On top of that, they have to actually update the row to mark it as locked, so the rest of your workers are sitting there waiting while one of them propagates its lock to disk (and the disks of however many servers you're replicating to). QueueClassic got some mileage out of the novel idea of randomly picking a row near the front of the queue to lock, but I can't still seem to get more than an an extra few hundred jobs per second out of it under heavy load.

So, many developers have started going straight t

	;; File: src/some_app/middleware.clj
	(defn open-gates [request]
	true)
	(def rules [{:pattern #"^/admin.*"
	:handler admin-access
	:redirect "/notauthorized"},
	{:pattern #"^\/vclass.*"
	:handler user-access
	:redirect "/notauthorized"},
	{:pattern #"^\/api.*"

	(defn ->Function
	[f]
	(reify java.util.function.Function
	(apply [_ obj] (f obj))))
	(defn future-map
	[cf f]
	(.thenApply cf (->Function f)))
	(defn future->ch
	([cf]
	(future->ch cf (async/chan 1) true))

	(ns plokal.cheshire
	(:require [cheshire.generate :refer [add-encoder]]
	[cheshire.core :as json])
	(:import [com.fasterxml.jackson.core JsonGenerator]
	(org.postgresql.geometric PGpoint)))

	(add-encoder
	PGpoint
	(fn [^PGpoint data ^JsonGenerator jsonGenerator]
	(.writeString jsonGenerator (json/generate-string {:type :Point

	go env
	GOARCH="amd64"
	GOBIN="/usr/local/go/bin"
	GOCACHE="/Users/dv/Library/Caches/go-build"
	GOEXE=""
	GOFLAGS=""
	GOHOSTARCH="amd64"
	GOHOSTOS="darwin"
	GOOS="darwin"
	GOPATH="/Users/dv/go"

	package httplib

	import (
	"net/http"
	"net/http/httptest"
	"net/url"
	"testing"


	"github.com/manyminds/api2go"