lockless-fifo accepts sqlite

cmd/pg-lockless-fifo-demo/README.md

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+https://trychroma.com/engineering/wal3
+
+(generally with S3 but this is fine)
+
+1. GET (current_node, cksum) FROM head_pointer
+1. INSERT node (previous_node) VALUES (head_pointer) RETURNING node.id
+1. UPDATE head_pointer (current_node, cksum) VALUES (node.id, blockchain) IF head_pointer.cksum=cksum

cmd/pg-lockless-fifo-demo/main.go

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+package main
+
+import (
+	"context"
+	"database/sql"
+	"flag"
+	"log"
+	"os"
+	"time"
+
+	"pg/src/with"
+
+	_ "github.com/lib/pq"
+	_ "modernc.org/sqlite"
+)
+
+func main() {
+	if err := with.Context(run); err != nil {
+		panic(err)
+	}
+}
+
+func run(ctx context.Context) error {
+	fs := flag.NewFlagSet(os.Args[0], flag.ContinueOnError)
+	c := fs.String("c", "postgresql://pulsegres:pulsegres@localhost:15432", "conn string")
+	if err := fs.Parse(os.Args[1:]); err != nil {
+		panic(err)
+	}
+
+	return with.PSQL(ctx, *c, func(pg *sql.DB) error {
+		go with.Every(ctx, 5*time.Second, func() {
+			row := pg.QueryRowContext(ctx, `SELECT 1`)
+			var n int
+			if err := row.Err(); err != nil {
+				log.Println("query err:", err)
+			} else if err := row.Scan(&n); err != nil {
+				log.Println("scan err:", err)
+			} else {
+				log.Println("ping...")
+			}
+		})
+
+		<-ctx.Done()
+		return nil
+	})
+}