From 3391e3d34b10fe157c020fe6fa10c492257c98e6 Mon Sep 17 00:00:00 2001
From: Jakub Vrana <jakub@vrana.cz>
Date: Fri, 5 Apr 2013 23:02:06 -0700
Subject: [PATCH] Use (a = ? AND b = ?) instead of (a, b) IN (?, ?)

Summary: MySQL is not able to use indexes with searching for tuples.

Test Plan:
Explained the query before and after, saw `key_len` 16 instead of 8.
Also saw time 0.0 s instead of 2.9 s (but that was probably caused by warming up).

Reviewers: epriestley

Reviewed By: epriestley

CC: aran, Korvin

Differential Revision: https://secure.phabricator.com/D5580
---
 .../diffusion/query/browse/DiffusionSvnBrowseQuery.php    | 8 +++++---
 src/docs/developer/database.diviner                       | 4 ++++
 .../daemon/workers/query/PhabricatorWorkerLeaseQuery.php  | 6 +++---
 src/infrastructure/edges/editor/PhabricatorEdgeEditor.php | 6 +++---
 4 files changed, 15 insertions(+), 9 deletions(-)

diff --git a/src/applications/diffusion/query/browse/DiffusionSvnBrowseQuery.php b/src/applications/diffusion/query/browse/DiffusionSvnBrowseQuery.php
index 4e1467e6f7..074aaf92d0 100644
--- a/src/applications/diffusion/query/browse/DiffusionSvnBrowseQuery.php
+++ b/src/applications/diffusion/query/browse/DiffusionSvnBrowseQuery.php
@@ -102,7 +102,9 @@ final class DiffusionSvnBrowseQuery extends DiffusionBrowseQuery {
 
     $sql = array();
     foreach ($index as $row) {
-      $sql[] = '('.(int)$row['pathID'].', '.(int)$row['maxCommit'].')';
+      $sql[] =
+        '(pathID = '.(int)$row['pathID'].' AND '.
+        'svnCommit = '.(int)$row['maxCommit'].')';
     }
 
     $browse = queryfx_all(
@@ -112,13 +114,13 @@ final class DiffusionSvnBrowseQuery extends DiffusionBrowseQuery {
         WHERE repositoryID = %d
           AND parentID = %d
           AND existed = 1
-        AND (pathID, svnCommit) in (%Q)
+        AND (%Q)
         ORDER BY pathName',
       PhabricatorRepository::TABLE_FILESYSTEM,
       PhabricatorRepository::TABLE_PATH,
       $repository->getID(),
       $path_id,
-      implode(', ', $sql));
+      implode(' OR ', $sql));
 
     $loadable_commits = array();
     foreach ($browse as $key => $file) {
diff --git a/src/docs/developer/database.diviner b/src/docs/developer/database.diviner
index 8ad4e349f3..6b085039cc 100644
--- a/src/docs/developer/database.diviner
+++ b/src/docs/developer/database.diviner
@@ -96,6 +96,10 @@ Create all indexes necessary for fast query execution in most cases. Don't
 create indexes which are not used. You can analyze queries @{article:Using
 DarkConsole}.
 
+Older MySQL versions are not able to use indexes for tuple search:
+`(a, b) IN ((%s, %d), (%s, %d))`. Use `AND` and `OR` instead:
+`((a = %s AND b = %d) OR (a = %s AND b = %d))`.
+
 = Foreign Keys =
 
 We don't use InnoDB's foreign keys because our application is so great that
diff --git a/src/infrastructure/daemon/workers/query/PhabricatorWorkerLeaseQuery.php b/src/infrastructure/daemon/workers/query/PhabricatorWorkerLeaseQuery.php
index d4996e3e35..e54fb72d3e 100644
--- a/src/infrastructure/daemon/workers/query/PhabricatorWorkerLeaseQuery.php
+++ b/src/infrastructure/daemon/workers/query/PhabricatorWorkerLeaseQuery.php
@@ -171,14 +171,14 @@ final class PhabricatorWorkerLeaseQuery extends PhabricatorQuery {
         foreach ($rows as $row) {
           $in[] = qsprintf(
             $conn_w,
-            '(%d, %s)',
+            '(id = %d AND leaseOwner = %s)',
             $row['id'],
             $row['leaseOwner']);
         }
         $where[] = qsprintf(
           $conn_w,
-          '(id, leaseOwner) IN (%Q)',
-          '('.implode(', ', $in).')');
+          '(%Q)',
+          implode(' OR ', $in));
         break;
       default:
         throw new Exception("Unknown phase '{$phase}'!");
diff --git a/src/infrastructure/edges/editor/PhabricatorEdgeEditor.php b/src/infrastructure/edges/editor/PhabricatorEdgeEditor.php
index edda35cf0f..4ee2b68b84 100644
--- a/src/infrastructure/edges/editor/PhabricatorEdgeEditor.php
+++ b/src/infrastructure/edges/editor/PhabricatorEdgeEditor.php
@@ -306,7 +306,7 @@ final class PhabricatorEdgeEditor extends PhabricatorEditor {
       foreach ($edges as $edge) {
         $sql[] = qsprintf(
           $conn_w,
-          '(%s, %d, %s)',
+          '(src = %s AND type = %d AND dst = %s)',
           $edge['src'],
           $edge['type'],
           $edge['dst']);
@@ -323,9 +323,9 @@ final class PhabricatorEdgeEditor extends PhabricatorEditor {
       foreach (array_chunk($sql, 256) as $chunk) {
         queryfx(
           $conn_w,
-          'DELETE FROM %T WHERE (src, type, dst) IN (%Q)',
+          'DELETE FROM %T WHERE (%Q)',
           PhabricatorEdgeConfig::TABLE_NAME_EDGE,
-          implode(', ', $chunk));
+          implode(' OR ', $chunk));
       }
     }
   }