From 7b37f0d5afd47bc63a8efccbea900faea5a0e4e5 Mon Sep 17 00:00:00 2001
From: sdong <siying.d@fb.com>
Date: Tue, 22 Apr 2014 18:31:55 -0700
Subject: [PATCH] PlainTableReader to expose index size to users

Summary:
This is a temp solution to expose index sizes to users from PlainTableReader before we persistent them to files.
In this patch, the memory consumption of indexes used by PlainTableReader will be reported as two user defined properties, so that users can monitor them.

Test Plan:
Add a unit test.
make all check`

Reviewers: haobo, ljin

Reviewed By: haobo

CC: nkg-, yhchiang, igor, ljin, dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D18195
---
 db/plain_table_db_test.cc          | 15 ++++++++++++++-
 include/rocksdb/table_properties.h |  2 +-
 table/plain_table_reader.cc        | 19 +++++++++++++++----
 table/plain_table_reader.h         |  5 ++++-
 4 files changed, 34 insertions(+), 7 deletions(-)

diff --git a/db/plain_table_db_test.cc b/db/plain_table_db_test.cc
index 6a95a2585..8a2d85f58 100644
--- a/db/plain_table_db_test.cc
+++ b/db/plain_table_db_test.cc
@@ -190,7 +190,7 @@ class TestPlainTableReader : public PlainTableReader {
                          file_size, bloom_bits_per_key, hash_table_ratio,
                          index_sparseness, table_properties),
         expect_bloom_not_match_(expect_bloom_not_match) {
-    Status s = PopulateIndex();
+    Status s = PopulateIndex(const_cast<TableProperties*>(table_properties));
     ASSERT_TRUE(s.ok());
   }
 
@@ -265,6 +265,19 @@ TEST(PlainTableDBTest, Flush) {
       ASSERT_OK(Put("0000000000000bar", "v2"));
       ASSERT_OK(Put("1000000000000foo", "v3"));
       dbfull()->TEST_FlushMemTable();
+
+      TablePropertiesCollection ptc;
+      reinterpret_cast<DB*>(dbfull())->GetPropertiesOfAllTables(&ptc);
+      ASSERT_EQ(1, ptc.size());
+      auto row = ptc.begin();
+      auto tp = row->second;
+      ASSERT_EQ(
+          total_order ? "4" : "12",
+          (tp->user_collected_properties).at("plain_table_hash_table_size"));
+      ASSERT_EQ(
+          total_order ? "9" : "0",
+          (tp->user_collected_properties).at("plain_table_sub_index_size"));
+
       ASSERT_EQ("v3", Get("1000000000000foo"));
       ASSERT_EQ("v2", Get("0000000000000bar"));
     }
diff --git a/include/rocksdb/table_properties.h b/include/rocksdb/table_properties.h
index 55b83f441..aa8b8a0b8 100644
--- a/include/rocksdb/table_properties.h
+++ b/include/rocksdb/table_properties.h
@@ -23,7 +23,7 @@ namespace rocksdb {
 //      ++pos) {
 //   ...
 // }
-typedef std::map<std::string, std::string> UserCollectedProperties;
+typedef std::map<const std::string, std::string> UserCollectedProperties;
 
 // TableProperties contains a bunch of read-only properties of its associated
 // table.
diff --git a/table/plain_table_reader.cc b/table/plain_table_reader.cc
index 436d13bf3..02e8f12d4 100644
--- a/table/plain_table_reader.cc
+++ b/table/plain_table_reader.cc
@@ -103,8 +103,8 @@ PlainTableReader::PlainTableReader(
       kHashTableRatio(hash_table_ratio),
       kBloomBitsPerKey(bloom_bits_per_key),
       kIndexIntervalForSamePrefixKeys(index_sparseness),
-      table_properties_(table_properties),
-      data_end_offset_(table_properties_->data_size),
+      table_properties_(nullptr),
+      data_end_offset_(table_properties->data_size),
       user_key_len_(table_properties->fixed_key_len) {
   assert(kHashTableRatio >= 0.0);
 }
@@ -136,7 +136,7 @@ Status PlainTableReader::Open(
       bloom_bits_per_key, hash_table_ratio, index_sparseness, props));
 
   // -- Populate Index
-  s = new_reader->PopulateIndex();
+  s = new_reader->PopulateIndex(props);
   if (!s.ok()) {
     return s;
   }
@@ -363,7 +363,10 @@ void PlainTableReader::FillIndexes(
       index_size_, kSubIndexSize);
 }
 
-Status PlainTableReader::PopulateIndex() {
+Status PlainTableReader::PopulateIndex(TableProperties* props) {
+  assert(props != nullptr);
+  table_properties_.reset(props);
+
   // options.prefix_extractor is requried for a hash-based look-up.
   if (options_.prefix_extractor.get() == nullptr && kHashTableRatio != 0) {
     return Status::NotSupported(
@@ -408,6 +411,14 @@ Status PlainTableReader::PopulateIndex() {
   // From the temp data structure, populate indexes.
   FillIndexes(sub_index_size_needed, hash_to_offsets, entries_per_bucket);
 
+  // Fill two table properties.
+  // TODO(sdong): after we have the feature of storing index in file, this
+  // properties need to be populated to index_size instead.
+  props->user_collected_properties["plain_table_hash_table_size"] =
+      std::to_string(index_size_ * 4U);
+  props->user_collected_properties["plain_table_sub_index_size"] =
+      std::to_string(sub_index_size_needed);
+
   return Status::OK();
 }
 
diff --git a/table/plain_table_reader.h b/table/plain_table_reader.h
index ac2cb8744..7f0c3b537 100644
--- a/table/plain_table_reader.h
+++ b/table/plain_table_reader.h
@@ -86,6 +86,9 @@ class PlainTableReader: public TableReader {
   // PopulateIndex() builds index of keys. It must be called before any query
   // to the table.
   //
+  // props: the table properties object that need to be stored. Ownership of
+  //        the object will be passed.
+  //
   // index_ contains buckets size of index_size_, each is a
   // 32-bit integer. The lower 31 bits contain an offset value (explained below)
   // and the first bit of the integer indicates type of the offset.
@@ -121,7 +124,7 @@ class PlainTableReader: public TableReader {
   //    ....
   //   record N file offset:  fixedint32
   // <end>
-  Status PopulateIndex();
+  Status PopulateIndex(TableProperties* props);
 
  private:
   struct IndexRecord;