Add snowflake implementation

notes/unique-ids.ipynb

@@ -0,0 +1,180 @@
+{
+ "cells": [
+  {
+   "cell_type": "markdown",
+   "id": "d6ed707c",
+   "metadata": {},
+   "source": [
+    "### Flake id: Splitting 64 bits between time, process, and counter"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 18,
+   "id": "60d1cbf0",
+   "metadata": {},
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "40 Wed Nov  3 11:53:47 2004\n",
+      "41 Wed Sep  7 08:47:35 2039\n",
+      "42 Wed May 15 00:35:11 2109\n",
+      "43 Tue Sep 26 08:10:22 2248\n",
+      "44 Sun Jun 22 23:20:44 2527\n",
+      "45 Fri Dec 12 04:41:28 3084\n"
+     ]
+    }
+   ],
+   "source": [
+    "import time\n",
+    "\n",
+    "# Maximum time in ms for given number of bits\n",
+    "for bits in range(40, 46):\n",
+    "    ms_max = 2**bits\n",
+    "    print(bits, time.ctime(ms_max / 1000))"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 19,
+   "id": "527a1f0a",
+   "metadata": {},
+   "outputs": [
+    {
+     "data": {
+      "text/plain": [
+       "'1_0000_0000_0000_0000_0000_0000_0000_0000_0000_0000_1100_0000_1100_0000_0000_0001'"
+      ]
+     },
+     "execution_count": 19,
+     "metadata": {},
+     "output_type": "execute_result"
+    }
+   ],
+   "source": [
+    "# 42 bits are enough\n",
+    "\n",
+    "# Simple bit patterns for testing\n",
+    "ms_since_epoch = (1<<41) + 1\n",
+    "process_id = (1<<7) + 1\n",
+    "counter = (1<<14) + 1\n",
+    "\n",
+    "flake = (ms_since_epoch << (8+15) |\n",
+    "         process_id << (15) |\n",
+    "         counter)\n",
+    "\n",
+    "f\"{flake:_b}\""
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 20,
+   "id": "ce892afa",
+   "metadata": {},
+   "outputs": [
+    {
+     "data": {
+      "text/plain": [
+       "(4398046511104, 256, 32768)"
+      ]
+     },
+     "execution_count": 20,
+     "metadata": {},
+     "output_type": "execute_result"
+    }
+   ],
+   "source": [
+    "ms_max = (1<<41) * 2\n",
+    "\n",
+    "process_id_max = 1<<8\n",
+    "\n",
+    "counter_max = 1 << 15\n",
+    "ms_max, process_id_max, counter_max"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 21,
+   "id": "ab7600b7",
+   "metadata": {},
+   "outputs": [
+    {
+     "data": {
+      "text/plain": [
+       "'Wed May 15 00:35:11 2109'"
+      ]
+     },
+     "execution_count": 21,
+     "metadata": {},
+     "output_type": "execute_result"
+    }
+   ],
+   "source": [
+    "# Max. time for id\n",
+    "time.ctime(ms_max / 1000)"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 26,
+   "id": "ebc23d69",
+   "metadata": {},
+   "outputs": [
+    {
+     "data": {
+      "text/plain": [
+       "('time',\n",
+       " 1649714152347,\n",
+       " 'bits required',\n",
+       " 40.58535320753334,\n",
+       " 'ratio to max',\n",
+       " 2.6659445849131065)"
+      ]
+     },
+     "execution_count": 26,
+     "metadata": {},
+     "output_type": "execute_result"
+    }
+   ],
+   "source": [
+    "# Builtin time since epoch, in ns, converted to ms: \n",
+    "from math import log2\n",
+    "time_ms = int(time.time_ns() / 1e6)\n",
+    "\"time\", time_ms, \"bits required\", log2(time_ms), \"ratio to max\", 2**42/time_ms\n"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "id": "7a06517b",
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "\n"
+   ]
+  }
+ ],
+ "metadata": {
+  "kernelspec": {
+   "display_name": "Python 3 (ipykernel)",
+   "language": "python",
+   "name": "python3"
+  },
+  "language_info": {
+   "codemirror_mode": {
+    "name": "ipython",
+    "version": 3
+   },
+   "file_extension": ".py",
+   "mimetype": "text/x-python",
+   "name": "python",
+   "nbconvert_exporter": "python",
+   "pygments_lexer": "ipython3",
+   "version": "3.9.10"
+  }
+ },
+ "nbformat": 4,
+ "nbformat_minor": 5
+}