Optimize count queries for pagination

models/common.ts

@@ -26,6 +26,13 @@ export default class Model extends TypeORM.BaseEntity {
     )[0]['COUNT(*)']);
   }
 
+  static async countForPagination(where) {
+    const queryBuilder = where instanceof TypeORM.SelectQueryBuilder
+                       ? where
+                       : this.createQueryBuilder().where(where);
+    return await queryBuilder.getCount();
+  }
+
   static async queryAll(queryBuilder) {
     return await queryBuilder.getMany();
   }

modules/contest.js

@@ -14,7 +14,7 @@ app.get('/contests', async (req, res) => {
     if (res.locals.user && res.locals.user.is_admin) where = {}
     else where = { is_public: true };
 
-    let paginate = syzoj.utils.paginate(await Contest.count(where), req.query.page, syzoj.config.page.contest);
+    let paginate = syzoj.utils.paginate(await Contest.countForPagination(where), req.query.page, syzoj.config.page.contest);
     let contests = await Contest.queryPage(paginate, where, {
       start_time: 'DESC'
     });
@@ -369,7 +369,7 @@ app.get('/contest/:id/submissions', async (req, res) => {
     query.andWhere('type = 1')
          .andWhere('type_info = :contest_id', { contest_id });
 
-    let paginate = syzoj.utils.paginate(await JudgeState.countQuery(query), req.query.page, syzoj.config.page.judge_state);
+    let paginate = syzoj.utils.paginate(await JudgeState.countForPagination(query), req.query.page, syzoj.config.page.judge_state);
     let judge_state = await JudgeState.queryPage(paginate, query, {
       submit_time: 'DESC'
     });

modules/discussion.js

@@ -16,7 +16,7 @@ app.get('/discussion/:type?', async (req, res) => {
     } else {
       where = { problem_id: null };
     }
-    let paginate = syzoj.utils.paginate(await Article.count(where), req.query.page, syzoj.config.page.discussion);
+    let paginate = syzoj.utils.paginate(await Article.countForPagination(where), req.query.page, syzoj.config.page.discussion);
     let articles = await Article.queryPage(paginate, where, {
       sort_time: 'DESC'
     });
@@ -52,7 +52,7 @@ app.get('/discussion/problem/:pid', async (req, res) => {
     }
 
     let where = { problem_id: pid };
-    let paginate = syzoj.utils.paginate(await Article.count(where), req.query.page, syzoj.config.page.discussion);
+    let paginate = syzoj.utils.paginate(await Article.countForPagination(where), req.query.page, syzoj.config.page.discussion);
     let articles = await Article.queryPage(paginate, where, {
       sort_time: 'DESC'
     });
@@ -85,7 +85,7 @@ app.get('/article/:id', async (req, res) => {
     article.content = await syzoj.utils.markdown(article.content);
 
     let where = { article_id: id };
-    let commentsCount = await ArticleComment.count(where);
+    let commentsCount = await ArticleComment.countForPagination(where);
     let paginate = syzoj.utils.paginate(commentsCount, req.query.page, syzoj.config.page.article_comment);
 
     let comments = await ArticleComment.queryPage(paginate, where, {

modules/problem.js

@@ -35,7 +35,7 @@ app.get('/problems', async (req, res) => {
       query.orderBy(sort, order.toUpperCase());
     }
 
-    let paginate = syzoj.utils.paginate(await Problem.countQuery(query), req.query.page, syzoj.config.page.problem);
+    let paginate = syzoj.utils.paginate(await Problem.countForPagination(query), req.query.page, syzoj.config.page.problem);
     let problems = await Problem.queryPage(paginate, query);
 
     await problems.forEachAsync(async problem => {
@@ -98,7 +98,7 @@ app.get('/problems/search', async (req, res) => {
       query.addOrderBy(sort, order.toUpperCase());
     }
 
-    let paginate = syzoj.utils.paginate(await Problem.countQuery(query), req.query.page, syzoj.config.page.problem);
+    let paginate = syzoj.utils.paginate(await Problem.countForPagination(query), req.query.page, syzoj.config.page.problem);
     let problems = await Problem.queryPage(paginate, query);
 
     await problems.forEachAsync(async problem => {

modules/user.js

@@ -12,7 +12,7 @@ app.get('/ranklist', async (req, res) => {
     if (!['ac_num', 'rating', 'id', 'username'].includes(sort) || !['asc', 'desc'].includes(order)) {
       throw new ErrorMessage('错误的排序参数。');
     }
-    let paginate = syzoj.utils.paginate(await User.count({ is_show: true }), req.query.page, syzoj.config.page.ranklist);
+    let paginate = syzoj.utils.paginate(await User.countForPagination({ is_show: true }), req.query.page, syzoj.config.page.ranklist);
     let ranklist = await User.queryPage(paginate, { is_show: true }, { [sort]: order.toUpperCase() });
     await ranklist.forEachAsync(async x => x.renderInformation());