From 026a30092ebe13c1c3a9f8e2b1a90680a28d10c7 Mon Sep 17 00:00:00 2001
From: Nikita Vasilev <nekitvas@gmail.com>
Date: Tue, 15 Jan 2019 17:49:22 +0300
Subject: [PATCH] added alter

---
 dbms/src/Storages/AlterCommands.cpp    | 33 ++++++++++++++++++++++----
 dbms/src/Storages/StorageMergeTree.cpp |  2 +-
 2 files changed, 30 insertions(+), 5 deletions(-)

diff --git a/dbms/src/Storages/AlterCommands.cpp b/dbms/src/Storages/AlterCommands.cpp
index a32d37dcea3..ae36da3cb0e 100644
--- a/dbms/src/Storages/AlterCommands.cpp
+++ b/dbms/src/Storages/AlterCommands.cpp
@@ -321,7 +321,7 @@ void AlterCommand::apply(ColumnsDescription & columns_description, ASTPtr & orde
         if (std::any_of(
                 indexes_decl_ast->children.cbegin(),
                 indexes_decl_ast->children.cend(),
-                [this](const ASTPtr & index_ast){
+                [this](const ASTPtr & index_ast) {
                     return typeid_cast<const ASTIndexDeclaration &>(*index_ast).name == index_name;
                 }))
         {
@@ -332,12 +332,37 @@ void AlterCommand::apply(ColumnsDescription & columns_description, ASTPtr & orde
                                 ErrorCodes::ILLEGAL_COLUMN};
         }
 
-        //auto insert_it = indexes_decl_ast->children.end();
-        // TODO: implementation
+        auto insert_it = indexes_decl_ast->children.end();
+
+        if (!after_index_name.empty())
+        {
+            insert_it = std::find_if(
+                    indexes_decl_ast->children.begin(),
+                    indexes_decl_ast->children.end(),
+                    [this](const ASTPtr & index_ast) {
+                        return typeid_cast<const ASTIndexDeclaration &>(*index_ast).name == after_index_name;
+                    });
+            if (insert_it == indexes_decl_ast->children.end()) {
+                throw Exception("Wrong index name. Cannot find index `" + after_index_name + "` to insert after.",
+                        ErrorCodes::LOGICAL_ERROR);
+            }
+        }
+        indexes_decl_ast->children.emplace(insert_it, index_decl);
     }
     else if (type == DROP_INDEX)
     {
-        // TODO: implementation
+        auto erase_it = std::find_if(
+                indexes_decl_ast->children.begin(),
+                indexes_decl_ast->children.end(),
+                [this](const ASTPtr & index_ast) {
+                    return typeid_cast<const ASTIndexDeclaration &>(*index_ast).name == index_name;
+                });
+        if (erase_it == indexes_decl_ast->children.end())
+        {
+            throw Exception("Wrong index name. Cannot find index `" + index_name + "` to drop.",
+                    ErrorCodes::LOGICAL_ERROR);
+        }
+        indexes_decl_ast->children.erase(erase_it);
     }
     else
         throw Exception("Wrong parameter type in ALTER query", ErrorCodes::LOGICAL_ERROR);
diff --git a/dbms/src/Storages/StorageMergeTree.cpp b/dbms/src/Storages/StorageMergeTree.cpp
index 1fd0f422975..39dba4ed109 100644
--- a/dbms/src/Storages/StorageMergeTree.cpp
+++ b/dbms/src/Storages/StorageMergeTree.cpp
@@ -245,7 +245,7 @@ void StorageMergeTree::alter(
 
     /// Reinitialize primary key because primary key column types might have changed.
     data.setPrimaryKeyAndColumns(new_order_by_ast, new_primary_key_ast, new_columns);
-    data.setSkipIndexes(data.skip_indexes_ast);
+    data.setSkipIndexes(new_indexes_ast);
 
     for (auto & transaction : transactions)
         transaction->commit();