Adapt three unit tests with newer compiler/libraries (#4562)

Summary:
This fixes three tests that fail with relatively recent tools and libraries:

The tests are:

* `spatial_db_test`
* `table_test`
* `db_universal_compaction_test`

I'm using:

* `gcc` 7.3.0
* `glibc` 2.27
* `snappy` 1.1.7
* `gflags` 2.2.1
* `zlib` 1.2.11
* `bzip2` 1.0.6.0.1
* `lz4` 1.8.2
* `jemalloc` 5.0.1

The versions used in the Travis environment (which is two Ubuntu LTS versions behind the current one and doesn't use `lz4` or `jemalloc`) don't seem to have a problem. However, to be safe, I verified that these tests pass with and without my changes in a trusty Docker container without `lz4` and `jemalloc`.

However, I do get an unrelated set of other failures when using a trusty Docker container that uses `lz4` and `jemalloc`:

```
db/db_universal_compaction_test.cc:506: Failure
Value of: num + 1
  Actual: 3
Expected: NumSortedRuns(1)
Which is: 4
[  FAILED  ] UniversalCompactionNumLevels/DBTestUniversalCompaction.DynamicUniversalCompactionReadAmplification/0, where GetParam() = (1, false) (1189 ms)
[ RUN      ] UniversalCompactionNumLevels/DBTestUniversalCompaction.DynamicUniversalCompactionReadAmplification/1
db/db_universal_compaction_test.cc:506: Failure
Value of: num + 1
  Actual: 3
Expected: NumSortedRuns(1)
Which is: 4
[  FAILED  ] UniversalCompactionNumLevels/DBTestUniversalCompaction.DynamicUniversalCompactionReadAmplification/1, where GetParam() = (1, true) (1246 ms)
[ RUN      ] UniversalCompactionNumLevels/DBTestUniversalCompaction.DynamicUniversalCompactionReadAmplification/2
db/db_universal_compaction_test.cc:506: Failure
Value of: num + 1
  Actual: 3
Expected: NumSortedRuns(1)
Which is: 4
[  FAILED  ] UniversalCompactionNumLevels/DBTestUniversalCompaction.DynamicUniversalCompactionReadAmplification/2, where GetParam() = (3, false) (1237 ms)
[ RUN      ] UniversalCompactionNumLevels/DBTestUniversalCompaction.DynamicUniversalCompactionReadAmplification/3
db/db_universal_compaction_test.cc:506: Failure
Value of: num + 1
  Actual: 3
Expected: NumSortedRuns(1)
Which is: 4
[  FAILED  ] UniversalCompactionNumLevels/DBTestUniversalCompaction.DynamicUniversalCompactionReadAmplification/3, where GetParam() = (3, true) (1195 ms)
[ RUN      ] UniversalCompactionNumLevels/DBTestUniversalCompaction.DynamicUniversalCompactionReadAmplification/4
db/db_universal_compaction_test.cc:506: Failure
Value of: num + 1
  Actual: 3
Expected: NumSortedRuns(1)
Which is: 4
[  FAILED  ] UniversalCompactionNumLevels/DBTestUniversalCompaction.DynamicUniversalCompactionReadAmplification/4, where GetParam() = (5, false) (1161 ms)
[ RUN      ] UniversalCompactionNumLevels/DBTestUniversalCompaction.DynamicUniversalCompactionReadAmplification/5
db/db_universal_compaction_test.cc:506: Failure
Value of: num + 1
  Actual: 3
Expected: NumSortedRuns(1)
Which is: 4
[  FAILED  ] UniversalCompactionNumLevels/DBTestUniversalCompaction.DynamicUniversalCompactionReadAmplification/5, where GetParam() = (5, true) (1229 ms)
```

I haven't attempted to fix these since I'm not using trusty and Travis doesn't use `lz4` and `jemalloc`. However, the final commit in this PR does at least fix the compilation errors that occur when using trusty's version of `lz4`.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4562

Differential Revision: D10510917

Pulled By: maysamyabandeh

fbshipit-source-id: 59534042015ec339270e5fc2f6ac4d859370d189

db/db_universal_compaction_test.cc

@@ -1154,7 +1154,7 @@ TEST_P(DBTestUniversalCompaction, UniversalCompactionCompressRatio2) {
     dbfull()->TEST_WaitForFlushMemTable();
     dbfull()->TEST_WaitForCompact();
   }
-  ASSERT_LT(TotalSize(), 120000U * 12 * 0.8 + 120000 * 2);
+  ASSERT_LT(TotalSize(), 120000U * 12 * 0.82 + 120000 * 2);
 }
 
 #ifndef ROCKSDB_VALGRIND_RUN

table/table_test.cc

@@ -2730,9 +2730,9 @@ static void DoCompressionTest(CompressionType comp) {
   ASSERT_TRUE(Between(c.ApproximateOffsetOf("abc"),       0,      0));
   ASSERT_TRUE(Between(c.ApproximateOffsetOf("k01"),       0,      0));
   ASSERT_TRUE(Between(c.ApproximateOffsetOf("k02"),       0,      0));
-  ASSERT_TRUE(Between(c.ApproximateOffsetOf("k03"),    2000,   3000));
-  ASSERT_TRUE(Between(c.ApproximateOffsetOf("k04"),    2000,   3000));
-  ASSERT_TRUE(Between(c.ApproximateOffsetOf("xyz"),    4000,   6100));
+  ASSERT_TRUE(Between(c.ApproximateOffsetOf("k03"),    2000,   3500));
+  ASSERT_TRUE(Between(c.ApproximateOffsetOf("k04"),    2000,   3500));
+  ASSERT_TRUE(Between(c.ApproximateOffsetOf("xyz"),    4000,   6500));
   c.ResetTableReader();
 }
 

util/compression.h

@@ -790,6 +790,7 @@ inline bool LZ4_Compress(const CompressionContext& ctx,
 #else   // up to r123
   outlen = LZ4_compress_limitedOutput(input, &(*output)[output_header_len],
                                       static_cast<int>(length), compress_bound);
+  (void)ctx;
 #endif  // LZ4_VERSION_NUMBER >= 10400
 
   if (outlen == 0) {
@@ -853,6 +854,7 @@ inline CacheAllocationPtr LZ4_Uncompress(const UncompressionContext& ctx,
   *decompress_size = LZ4_decompress_safe(input_data, output.get(),
                                          static_cast<int>(input_length),
                                          static_cast<int>(output_len));
+  (void)ctx;
 #endif  // LZ4_VERSION_NUMBER >= 10400
 
   if (*decompress_size < 0) {

utilities/spatialdb/spatial_db_test.cc

@@ -94,7 +94,7 @@ TEST_F(SpatialDBTest, FeatureSetSerializeTest) {
   ASSERT_EQ(deserialized.Get("m").get_double(), 3.25);
 
   // corrupted serialization
-  serialized = serialized.substr(0, serialized.size() - 4);
+  serialized = serialized.substr(0, serialized.size() - 1);
   deserialized.Clear();
   ASSERT_TRUE(!deserialized.Deserialize(serialized));
 }