fix: support returning rows larger than 10MB. (databendlabs#17344)

src/query/service/src/servers/http/v1/query/page_manager.rs

@@ -143,6 +143,9 @@ impl PageManager {
                 i += 1;
             } else {
                 *remain_size = 0;
+                if res.is_empty() && i == 0 {
+                    i += 1
+                }
             }
         }
         res.extend_from_slice(&rows[..i]);
@@ -163,7 +166,11 @@ impl PageManager {
                     remain_size -= size;
                     remain_rows -= 1;
                 } else {
-                    self.row_buffer.push_front(row);
+                    if res.is_empty() {
+                        res.push(row);
+                    } else {
+                        self.row_buffer.push_front(row);
+                    }
                     remain_size = 0;
                 }
             } else {

tests/suites/1_stateful/09_http_handler/09_0004_large_row.result

@@ -0,0 +1,3 @@
+1
+1
+"/v1/query/09_004/final"

tests/suites/1_stateful/09_http_handler/09_0004_large_row.sh

@@ -0,0 +1,12 @@
+#!/usr/bin/env bash
+
+CURDIR=$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)
+. "$CURDIR"/../../../shell_env.sh
+
+qid="09_004"
+curl -s --header 'Content-Type: application/json' --header "X-DATABEND-QUERY-ID: $qid" --request POST '127.0.0.1:8000/v1/query/' \
+ --data-raw $'{"sql": "select json_array_agg(json_object(\'num\',number)), (number % 2) as s from numbers(2000000) group by s;", "pagination": { "wait_time_secs": 5}}' \
+ -u root: | jq '.data | length'
+
+curl -s --header 'Content-Type: application/json'  "127.0.0.1:8000/v1/query/$qid/page/1" \
+ -u root: | jq '(.data | length), .next_uri'