make corruption_test:CompactionInputErrorParanoid deterministic

Summary:
it writes ~10M data, default L0 compaction trigger is 4, plus 2 writer
buffer, so that can accommodate ~6M data before compaction happens for
sure. I guess encoding is doing a good job to shrink the data so that
sometime, compaction does not get triggered. I get test failure quite
often.

Test Plan: ran it multiple times and all got pass

Reviewers: igor, sdong

Reviewed By: sdong

CC: leveldb

Differential Revision: https://reviews.facebook.net/D17775

db/corruption_test.cc

@@ -326,7 +326,8 @@ TEST(CorruptionTest, CompactionInputError) {
 TEST(CorruptionTest, CompactionInputErrorParanoid) {
   Options options;
   options.paranoid_checks = true;
-  options.write_buffer_size = 1048576;
+  options.write_buffer_size = 131072;
+  options.max_write_buffer_number = 2;
   Reopen(&options);
   DBImpl* dbi = reinterpret_cast<DBImpl*>(db_);
 
@@ -349,7 +350,7 @@ TEST(CorruptionTest, CompactionInputErrorParanoid) {
   Status s;
   std::string tmp1, tmp2;
   bool failed = false;
-  for (int i = 0; i < 10000 && s.ok(); i++) {
+  for (int i = 0; i < 10000; i++) {
     s = db_->Put(WriteOptions(), Key(i, &tmp1), Value(i, &tmp2));
     if (!s.ok()) {
       failed = true;

include/rocksdb/options.h

@@ -257,6 +257,8 @@ struct ColumnFamilyOptions {
 
   // Number of files to trigger level-0 compaction. A value <0 means that
   // level-0 compaction will not be triggered by number of files at all.
+  //
+  // Default: 4
   int level0_file_num_compaction_trigger;
 
   // Soft limit on number of level-0 files. We start slowing down writes at this