Merge pull request #123 from malthe/fix-select-many-result-corruption-issue

Fix result corruption issue when selecting many rows

Author: malthe

CHANGES.md

@@ -1,5 +1,7 @@
 In next release ...
 
+- Fix issue where larger results would sometimes have duplicates (#122).
+
 - Fixed an issue where the result row array type would use the record generic
   as the value type instead of `any` which was incorrect.
 

src/client.ts

@@ -920,10 +920,7 @@ export class ClientImpl {
                     );
 
                     const remaining = bytes + read - size;
-                    if (remaining <= 0) {
-                        callback(row);
-                        row = null;
-                    } else {
+                    if (remaining > 0) {
                         const offset = startRowData + end;
                         buffer.writeInt8(mtype, offset - 7);
                         buffer.writeInt32BE(bytes - end - 1, offset - 6);
@@ -933,8 +930,12 @@ export class ClientImpl {
                         return read + end;
                     }
 
+                    callback(row);
+                    row = null;
+
                     // Keep track of how much data we've consumed.
                     frame += bytes;
+                    read += bytes;
 
                     // If the next message header doesn't fit, we
                     // break out and wait for more data to arrive.
@@ -943,8 +944,6 @@ export class ClientImpl {
                         this.expect = 5;
                         return read;
                     }
-
-                    read += bytes;
                 }
 
                 this.activeRow = null;

test/client.test.ts

@@ -301,6 +301,22 @@ describe('Query', () => {
         deepEqual(result.rows, [[1]]);
     });
 
+    test('Select many', async ({ client }) => {
+        const queryRunsCount = 10;
+        const idsCount = 10_000;
+        for (let i = 0; i < queryRunsCount; ++i) {
+            const result = await client.query(
+                'select id, id + 1, id + 2 from generate_series(1, $1) id',
+                [idsCount],
+            );
+            deepEqual(result.rows.length, idsCount);
+            for (const [i, j, k] of result.rows) {
+                deepEqual(i + 1, j);
+                deepEqual(i + 2, k);
+            }
+        }
+    });
+
     test('Stream', async ({ client }) => {
         const s = 'abcdefghijklmnopqrstuvxyz'.repeat(Math.pow(2, 17));
         const buffer = Buffer.from(s);