fix: QueryModeError for table-not-found, filterToSql null guard, int64 Math.trunc, reducer logging

- query-do: 4 throw sites use QueryModeError("TABLE_NOT_FOUND") instead of plain Error
- query-do: log reducer DO failures with this.log("error", ...) before collecting
- wasm-engine: filterToSql emits IS NULL/IS NOT NULL when value is null/undefined
- wasm-engine: registerDecodedColumnInner int64 path guards null + non-bigint with Math.trunc

Author: teamchong

src/query-do.ts

@@ -13,6 +13,7 @@ import { mergeQueryResults } from "./merge.js";
 import { decodeColumnarBatch, columnarBatchToRows } from "./columnar.js";
 import { coalesceRanges, fetchBounded, withRetry, withTimeout } from "./coalesce.js";
 import { R2SpillBackend, encodeColumnarRun } from "./r2-spill.js";
+import { QueryModeError } from "./errors.js";
 import {
   type Operator, type RowBatch,
   buildEdgePipeline, drainPipeline, estimateRowSize,
@@ -678,7 +679,7 @@ export class QueryDO extends DurableObject<Env> {
     const metaCached = !!meta;
     if (!meta) {
       meta = (await this.loadTableFromR2(query.table)) ?? undefined;
-      if (!meta) throw new Error(`Table "${query.table}" not found`);
+      if (!meta) throw new QueryModeError("TABLE_NOT_FOUND", `Table "${query.table}" not found`);
     }
 
     const { columns } = meta;
@@ -801,7 +802,7 @@ export class QueryDO extends DurableObject<Env> {
       let meta: TableMeta | undefined = this.footerCache.get(query.table);
       if (!meta) {
         meta = (await this.loadTableFromR2(query.table)) ?? undefined;
-        if (!meta) throw new Error(`Table "${query.table}" not found`);
+        if (!meta) throw new QueryModeError("TABLE_NOT_FOUND", `Table "${query.table}" not found`);
       }
 
       // Use operator pipeline for any query that could produce unbounded results:
@@ -1252,7 +1253,7 @@ export class QueryDO extends DurableObject<Env> {
       let leftMeta: TableMeta | undefined = this.footerCache.get(query.table);
       if (!leftMeta) {
         leftMeta = (await this.loadTableFromR2(query.table)) ?? undefined;
-        if (!leftMeta) throw new Error(`Table "${query.table}" not found`);
+        if (!leftMeta) throw new QueryModeError("TABLE_NOT_FOUND", `Table "${query.table}" not found`);
       }
 
       // Build left scan (no sort/limit/agg — those apply after join)
@@ -1272,7 +1273,7 @@ export class QueryDO extends DurableObject<Env> {
       let rightMeta: TableMeta | undefined = this.footerCache.get(join.right.table);
       if (!rightMeta) {
         rightMeta = (await this.loadTableFromR2(join.right.table)) ?? undefined;
-        if (!rightMeta) throw new Error(`Table "${join.right.table}" not found`);
+        if (!rightMeta) throw new QueryModeError("TABLE_NOT_FOUND", `Table "${join.right.table}" not found`);
       }
 
       // Build right scan
@@ -1907,7 +1908,9 @@ export class QueryDO extends DurableObject<Env> {
           if (s.status === "fulfilled") {
             results.push(s.value);
           } else {
-            failures.push(String(s.reason));
+            const reason = String(s.reason);
+            failures.push(reason);
+            this.log("error", "reducer_do_failed", { reason, tier });
           }
         }
         if (failures.length > 0) {

src/wasm-engine.ts

@@ -533,7 +533,10 @@ export class WasmEngine {
         const dataPtr = this.exports.alloc(rowCount * 8);
         if (!dataPtr) return false;
         const dst = new BigInt64Array(this.exports.memory.buffer, dataPtr, rowCount);
-        for (let i = 0; i < rowCount; i++) dst[i] = BigInt(values[i] as bigint ?? 0n);
+        for (let i = 0; i < rowCount; i++) {
+          const v = values[i];
+          dst[i] = v == null ? 0n : typeof v === "bigint" ? v : BigInt(Math.trunc(v as number));
+        }
         this.exports.registerTableInt64(tPtr, tLen, cPtr, cLen, dataPtr, rowCount);
         return true;
       }
@@ -1010,6 +1013,10 @@ const COMPARISON_OP_MAP: Record<string, string> = { eq: "=", neq: "!=", gt: ">",
 function filterToSql(f: FilterOp): string {
   if (f.op === "is_null") return `${quote(f.column)} IS NULL`;
   if (f.op === "is_not_null") return `${quote(f.column)} IS NOT NULL`;
+  // null/undefined value with eq/neq → IS NULL / IS NOT NULL
+  if (f.value === null || f.value === undefined) {
+    return `${quote(f.column)} ${f.op === "neq" ? "IS NOT NULL" : "IS NULL"}`;
+  }
   if (f.op === "in" && Array.isArray(f.value)) {
     return `${quote(f.column)} IN (${f.value.map(v => typeof v === "string" ? `'${escapeSql(v)}'` : String(v)).join(", ")})`;
   }