Fix forecast data load and add byte-progress UI

pg now returns bigint/numeric as JS numbers so Arrow infers Int/Float64
instead of Dictionary<Utf8>. /data accumulates rows and emits a single
record batch to avoid dictionary REPLACEMENT messages that crash
Perspective's WASM reader. Forecast view streams the response body and
shows received/total bytes while loading. Drops stale public/ static
middleware that was shadowing the React build at /.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

package-lock.json

@@ -1105,7 +1105,6 @@
       "resolved": "https://registry.npmjs.org/pg/-/pg-8.20.0.tgz",
       "integrity": "sha512-ldhMxz2r8fl/6QkXnBD3CR9/xg694oT6DZQ2s6c/RI28OjtSOpxnPrUCGOBJ46RCUxcWdx3p6kw/xnDHjKvaRA==",
       "license": "MIT",
-      "peer": true,
       "dependencies": {
         "pg-connection-string": "^2.12.0",
         "pg-pool": "^3.13.0",

routes/operations.js

@@ -1,5 +1,5 @@
 const express = require('express');
-const { tableFromJSON, RecordBatchStreamWriter, RecordBatch } = require('apache-arrow');
+const { tableFromJSON, tableToIPC } = require('apache-arrow');
 const { applyTokens, buildWhere, buildExcludeClause, buildSetClause, esc } = require('../lib/sql_generator');
 const { fcTable } = require('../lib/utils');
 
@@ -88,21 +88,22 @@ module.exports = function(pool) {
             await client.query('BEGIN');
             await client.query(`DECLARE pf_cur CURSOR FOR SELECT * FROM ${tbl}`);
 
-            const writer = RecordBatchStreamWriter.throughNode();
-            writer.pipe(res);
-
-            let schema = null;
+            // Accumulate rows from the cursor, then emit a single Arrow record batch.
+            // Per-batch tableFromJSON() builds independent dictionaries, which forces the
+            // writer to emit dictionary REPLACEMENT messages between batches — Perspective's
+            // WASM Arrow reader crashes on those (memory access out of bounds).
+            const allRows = [];
             while (true) {
                 const { rows } = await client.query('FETCH 10000 FROM pf_cur');
                 if (!rows.length) break;
-                const t = tableFromJSON(rows);
-                if (!schema) { schema = t.schema; writer.write(schema); }
-                for (const rb of t.batches) writer.write(new RecordBatch(schema, rb.data));
+                for (const r of rows) allRows.push(r);
             }
-
-            writer.end();
             await client.query('COMMIT');
             committed = true;
+
+            const buf = tableToIPC(tableFromJSON(allRows), 'stream');
+            res.setHeader('Content-Length', String(buf.byteLength));
+            res.end(Buffer.from(buf.buffer, buf.byteOffset, buf.byteLength));
         } catch (err) {
             console.error(err);
             if (!res.headersSent) res.status(err.status || 500).json({ error: err.message });

server.js

@@ -1,14 +1,17 @@
 require('dotenv').config();
 const express = require('express');
 const cors    = require('cors');
-const { Pool } = require('pg');
+const { Pool, types } = require('pg');
+
+// Return bigint (oid 20) and numeric (oid 1700) as JS numbers instead of strings,
+// so apache-arrow's tableFromJSON infers Int/Float64 rather than Dictionary<Utf8>.
+types.setTypeParser(20, v => v === null ? null : Number(v));
+types.setTypeParser(1700, v => v === null ? null : Number(v));
 
 const app = express();
 app.use(cors());
 app.use(express.json());
-app.use(express.static('public'));
 app.use(express.static('public/app'));
-app.get('/', (req, res) => res.sendFile(__dirname + '/public/app/index.html'));
 
 const pool = new Pool({
     host:     process.env.DB_HOST,

ui/src/views/Forecast.jsx

@@ -35,6 +35,7 @@ export default function Forecast() {
   const [versionId, setVersionId] = useState('')
   const [loading,      setLoading]      = useState(false)
   const [largeDataset, setLargeDataset] = useState(false)
+  const [loadProgress, setLoadProgress] = useState(null)  // { received, total }
   const [msg,          setMsg]          = useState(null)
 
   // layouts
@@ -148,6 +149,7 @@ export default function Forecast() {
     if (!viewer) return
     setLoading(true)
     setLargeDataset(false)
+    setLoadProgress(null)
     setSlice({})
     expandDepthRef.current = null
     try {
@@ -156,8 +158,22 @@ export default function Forecast() {
         fetch(`/api/versions/${vid}/data`).then(async r => {
           if (!r.ok) { const { error } = await r.json(); throw new Error(error || 'Failed to load data') }
           const rowCount = parseInt(r.headers.get('X-Row-Count') || '0')
-          const buffer   = await r.arrayBuffer()
-          return { buffer, rowCount }
+          const total    = parseInt(r.headers.get('Content-Length') || '0') || null
+          const reader   = r.body.getReader()
+          const chunks   = []
+          let received   = 0
+          setLoadProgress({ received: 0, total })
+          while (true) {
+            const { done, value } = await reader.read()
+            if (done) break
+            chunks.push(value)
+            received += value.byteLength
+            setLoadProgress({ received, total })
+          }
+          const merged = new Uint8Array(received)
+          let pos = 0
+          for (const c of chunks) { merged.set(c, pos); pos += c.byteLength }
+          return { buffer: merged.buffer, rowCount }
         }),
         fetch(`/api/sources/${sid}/cols`).then(r => r.json()),
       ])
@@ -577,8 +593,24 @@ export default function Forecast() {
         {/* Perspective viewer */}
         <div className="relative flex-1 min-w-0">
           {loading && (
-            <div className="absolute inset-0 flex items-center justify-center bg-gray-50 z-10">
+            <div className="absolute inset-0 flex flex-col items-center justify-center bg-gray-50 z-10 gap-2">
               <span className="text-sm text-gray-400">Loading…</span>
+              {loadProgress && (
+                <>
+                  <span className="text-xs text-gray-400 font-mono">
+                    {fmtBytes(loadProgress.received)}
+                    {loadProgress.total ? ` / ${fmtBytes(loadProgress.total)}` : ''}
+                  </span>
+                  {loadProgress.total > 0 && (
+                    <div className="w-48 h-1 bg-gray-200 rounded overflow-hidden">
+                      <div
+                        className="h-full bg-blue-400 transition-all"
+                        style={{ width: `${Math.min(100, (loadProgress.received / loadProgress.total) * 100)}%` }}
+                      />
+                    </div>
+                  )}
+                </>
+              )}
             </div>
           )}
           {!loading && largeDataset && (
@@ -706,6 +738,12 @@ export default function Forecast() {
 
 const inp = 'border border-gray-200 rounded px-2 py-1 text-xs flex-1 bg-white min-w-0'
 
+function fmtBytes(n) {
+  if (n < 1024) return `${n} B`
+  if (n < 1048576) return `${(n / 1024).toFixed(1)} KB`
+  return `${(n / 1048576).toFixed(1)} MB`
+}
+
 function fmtStamp(stamp) {
   return new Date(stamp).toLocaleString(undefined, { month: 'short', day: 'numeric', hour: 'numeric', minute: '2-digit' })
 }