From b41a3bc4da80df1caa76b3478512f78da3f66cfe Mon Sep 17 00:00:00 2001
From: Igor Canadi <icanadi@fb.com>
Date: Thu, 27 Feb 2014 16:44:26 -0800
Subject: [PATCH] [CF] Change flow of CreateColumnFamily

Summary:
Previously, we first wrote to the manifest and then created internal data structure.
Now, we first create internal data structure. That way, we can write out internal comparator to the manifest

Test Plan: column_family_test

Reviewers: dhruba, haobo

CC: leveldb

Differential Revision: https://reviews.facebook.net/D16425
---
 db/db_impl.cc | 33 ++++++++++++++++++++++++++-------
 1 file changed, 26 insertions(+), 7 deletions(-)

diff --git a/db/db_impl.cc b/db/db_impl.cc
index 1500a0dc8..615f0190c 100644
--- a/db/db_impl.cc
+++ b/db/db_impl.cc
@@ -3063,17 +3063,27 @@ Status DBImpl::CreateColumnFamily(const ColumnFamilyOptions& options,
   edit.AddColumnFamily(column_family_name);
   uint32_t new_id = versions_->GetColumnFamilySet()->GetNextColumnFamilyID();
   edit.SetColumnFamily(new_id);
+  auto cfd = versions_->CreateColumnFamily(options, &edit);
+  assert(cfd != nullptr);
+  edit.SetComparatorName(cfd->internal_comparator().user_comparator()->Name());
 
   Status s = versions_->LogAndApply(default_cf_handle_->cfd(), &edit, &mutex_);
   if (s.ok()) {
-    // add to internal data structures
-    auto cfd = versions_->CreateColumnFamily(options, &edit);
     *handle = new ColumnFamilyHandleImpl(cfd, this, &mutex_);
+  } else {
+    *handle = nullptr;
+    cfd->Unref();
+    delete cfd;
   }
   mutex_.Unlock();
 
-  Log(options_.info_log, "Created column family \"%s\"",
-      column_family_name.c_str());
+  if (s.ok()) {
+    Log(options_.info_log, "Created column family \"%s\" (ID %u)",
+        column_family_name.c_str(), (unsigned)cfd->GetID());
+  } else {
+    Log(options_.info_log, "Creating column family \"%s\" FAILED -- %s",
+        column_family_name.c_str(), s.ToString().c_str());
+  }
   return s;
 }
 
@@ -3083,17 +3093,19 @@ Status DBImpl::DropColumnFamily(ColumnFamilyHandle* column_family) {
   if (cfd->GetID() == 0) {
     return Status::InvalidArgument("Can't drop default column family");
   }
-  Log(options_.info_log, "Dropping column family with id %u\n", cfd->GetID());
 
   VersionEdit edit;
   edit.DropColumnFamily();
   edit.SetColumnFamily(cfd->GetID());
 
   MutexLock l(&mutex_);
+  Status s;
   if (cfd->IsDropped()) {
-    return Status::InvalidArgument("Column family already dropped!\n");
+    s = Status::InvalidArgument("Column family already dropped!\n");
+  }
+  if (s.ok()) {
+    s = versions_->LogAndApply(cfd, &edit, &mutex_);
   }
-  Status s = versions_->LogAndApply(cfd, &edit, &mutex_);
   if (s.ok()) {
     cfd->SetDropped();
     // DB is holding one reference to each column family when it's alive,
@@ -3103,6 +3115,13 @@ Status DBImpl::DropColumnFamily(ColumnFamilyHandle* column_family) {
     }
   }
 
+  if (s.ok()) {
+    Log(options_.info_log, "Dropped column family with id %u\n", cfd->GetID());
+  } else {
+    Log(options_.info_log, "Dropping column family with id %u FAILED -- %s\n",
+        cfd->GetID(), s.ToString().c_str());
+  }
+
   return s;
 }