Fix PlainTableReader not to crash sst_dump (#5940)

Summary:
Plain table SSTs could crash sst_dump because of a bug in
PlainTableReader that can leave table_properties_ as null. Even if it
was intended not to keep the table properties in some cases, they were
leaked on the offending code path.

Steps to reproduce:

    $ db_bench --benchmarks=fillrandom --num=2000000 --use_plain_table --prefix-size=12
    $ sst_dump --file=0000xx.sst --show_properties
    from [] to []
    Process /dev/shm/dbbench/000014.sst
    Sst file format: plain table
    Raw user collected properties
    ------------------------------
    Segmentation fault (core dumped)

Also added missing unit testing of plain table full_scan_mode, and
an assertion in NewIterator to check for regression.
Pull Request resolved: #5940

Test Plan: new unit test, manual, make check

Differential Revision: D18018145

Pulled By: pdillinger

fbshipit-source-id: 4310c755e824c4cd6f3f86a3abc20dfa417c5e07

db/plain_table_db_test.cc

@@ -302,6 +302,7 @@ class TestPlainTableReader : public PlainTableReader {
         EXPECT_TRUE(num_blocks_ptr != props->user_collected_properties.end());
       }
     }
+    table_properties_.reset(props);
   }
 
   ~TestPlainTableReader() override {}
@@ -396,7 +397,9 @@ TEST_P(PlainTableDBTest, Flush) {
   for (size_t huge_page_tlb_size = 0; huge_page_tlb_size <= 2 * 1024 * 1024;
        huge_page_tlb_size += 2 * 1024 * 1024) {
     for (EncodingType encoding_type : {kPlain, kPrefix}) {
-    for (int bloom_bits = 0; bloom_bits <= 117; bloom_bits += 117) {
+    for (int bloom = -1; bloom <= 117; bloom += 117) {
+      const int bloom_bits = std::max(bloom, 0);
+      const bool full_scan_mode = bloom < 0;
       for (int total_order = 0; total_order <= 1; total_order++) {
         for (int store_index_in_file = 0; store_index_in_file <= 1;
              ++store_index_in_file) {
@@ -414,7 +417,7 @@ TEST_P(PlainTableDBTest, Flush) {
             plain_table_options.index_sparseness = 2;
             plain_table_options.huge_page_tlb_size = huge_page_tlb_size;
             plain_table_options.encoding_type = encoding_type;
-            plain_table_options.full_scan_mode = false;
+            plain_table_options.full_scan_mode = full_scan_mode;
             plain_table_options.store_index_in_file = store_index_in_file;
 
             options.table_factory.reset(
@@ -427,7 +430,7 @@ TEST_P(PlainTableDBTest, Flush) {
             plain_table_options.index_sparseness = 16;
             plain_table_options.huge_page_tlb_size = huge_page_tlb_size;
             plain_table_options.encoding_type = encoding_type;
-            plain_table_options.full_scan_mode = false;
+            plain_table_options.full_scan_mode = full_scan_mode;
             plain_table_options.store_index_in_file = store_index_in_file;
 
             options.table_factory.reset(
@@ -454,20 +457,36 @@ TEST_P(PlainTableDBTest, Flush) {
           auto row = ptc.begin();
           auto tp = row->second;
 
-          if (!store_index_in_file) {
-            ASSERT_EQ(total_order ? "4" : "12",
-                      (tp->user_collected_properties)
-                          .at("plain_table_hash_table_size"));
-            ASSERT_EQ("0", (tp->user_collected_properties)
-                               .at("plain_table_sub_index_size"));
+          if (full_scan_mode) {
+            // Does not support Get/Seek
+            std::unique_ptr<Iterator> iter(dbfull()->NewIterator(ReadOptions()));
+            iter->SeekToFirst();
+            ASSERT_TRUE(iter->Valid());
+            ASSERT_EQ("0000000000000bar", iter->key().ToString());
+            ASSERT_EQ("v2", iter->value().ToString());
+            iter->Next();
+            ASSERT_TRUE(iter->Valid());
+            ASSERT_EQ("1000000000000foo", iter->key().ToString());
+            ASSERT_EQ("v3", iter->value().ToString());
+            iter->Next();
+            ASSERT_TRUE(!iter->Valid());
+            ASSERT_TRUE(iter->status().ok());
           } else {
-            ASSERT_EQ("0", (tp->user_collected_properties)
-                               .at("plain_table_hash_table_size"));
-            ASSERT_EQ("0", (tp->user_collected_properties)
-                               .at("plain_table_sub_index_size"));
+            if (!store_index_in_file) {
+              ASSERT_EQ(total_order ? "4" : "12",
+                        (tp->user_collected_properties)
+                            .at("plain_table_hash_table_size"));
+              ASSERT_EQ("0", (tp->user_collected_properties)
+                                 .at("plain_table_sub_index_size"));
+            } else {
+              ASSERT_EQ("0", (tp->user_collected_properties)
+                                 .at("plain_table_hash_table_size"));
+              ASSERT_EQ("0", (tp->user_collected_properties)
+                                 .at("plain_table_sub_index_size"));
+            }
+            ASSERT_EQ("v3", Get("1000000000000foo"));
+            ASSERT_EQ("v2", Get("0000000000000bar"));
           }
-          ASSERT_EQ("v3", Get("1000000000000foo"));
-          ASSERT_EQ("v2", Get("0000000000000bar"));
         }
         }
       }

table/plain/plain_table_reader.cc

@@ -183,6 +183,8 @@ Status PlainTableReader::Open(
     // can be used.
     new_reader->full_scan_mode_ = true;
   }
+  // PopulateIndex can add to the props, so don't store them until now
+  new_reader->table_properties_.reset(props);
 
   if (immortal_table && new_reader->file_info_.is_mmap_mode) {
     new_reader->dummy_cleanable_.reset(new Cleanable());
@@ -199,6 +201,9 @@ InternalIterator* PlainTableReader::NewIterator(
     const ReadOptions& options, const SliceTransform* /* prefix_extractor */,
     Arena* arena, bool /*skip_filters*/, TableReaderCaller /*caller*/,
     size_t /*compaction_readahead_size*/) {
+  // Not necessarily used here, but make sure this has been initialized
+  assert(table_properties_);
+
   bool use_prefix_seek = !IsTotalOrderMode() && !options.total_order_seek;
   if (arena == nullptr) {
     return new PlainTableIterator(this, use_prefix_seek);
@@ -291,7 +296,6 @@ Status PlainTableReader::PopulateIndex(TableProperties* props,
                                        size_t index_sparseness,
                                        size_t huge_page_tlb_size) {
   assert(props != nullptr);
-  table_properties_.reset(props);
 
   BlockContents index_block_contents;
   Status s = ReadMetaBlock(file_info_.file.get(), nullptr /* prefetch_buffer */,
@@ -351,7 +355,7 @@ Status PlainTableReader::PopulateIndex(TableProperties* props,
     // Allocate bloom filter here for total order mode.
     if (IsTotalOrderMode()) {
       AllocateBloom(bloom_bits_per_key,
-                    static_cast<uint32_t>(table_properties_->num_entries),
+                    static_cast<uint32_t>(props->num_entries),
                     huge_page_tlb_size);
     }
   } else if (bloom_in_file) {

table/plain/plain_table_reader.h

@@ -165,7 +165,9 @@ class PlainTableReader: public TableReader {
   const ImmutableCFOptions& ioptions_;
   std::unique_ptr<Cleanable> dummy_cleanable_;
   uint64_t file_size_;
+ protected: // for testing
   std::shared_ptr<const TableProperties> table_properties_;
+ private:
 
   bool IsFixedLength() const {
     return user_key_len_ != kPlainTableVariableLength;

tools/sst_dump_tool.cc

@@ -740,17 +740,19 @@ int SSTDumpTool::Run(int argc, char** argv, Options options) {
         total_data_block_size += table_properties->data_size;
         total_index_block_size += table_properties->index_size;
         total_filter_block_size += table_properties->filter_size;
-      }
-      if (show_properties) {
-        fprintf(stdout,
-                "Raw user collected properties\n"
-                "------------------------------\n");
-        for (const auto& kv : table_properties->user_collected_properties) {
-          std::string prop_name = kv.first;
-          std::string prop_val = Slice(kv.second).ToString(true);
-          fprintf(stdout, "  # %s: 0x%s\n", prop_name.c_str(),
-                  prop_val.c_str());
+        if (show_properties) {
+          fprintf(stdout,
+                  "Raw user collected properties\n"
+                  "------------------------------\n");
+          for (const auto& kv : table_properties->user_collected_properties) {
+            std::string prop_name = kv.first;
+            std::string prop_val = Slice(kv.second).ToString(true);
+            fprintf(stdout, "  # %s: 0x%s\n", prop_name.c_str(),
+                    prop_val.c_str());
+          }
         }
+      } else {
+        fprintf(stderr, "Reader unexpectedly returned null properties\n");
       }
     }
   }