Expose db stress tests

[riversand963]

Summary: expose db stress test by providing db_stress_tool.h in public header.
This PR does the following:

• adds a new header, db_stress_tool.h, in include/rocksdb/
• renames db_stress.cc to db_stress_tool.cc
• adds a db_stress.cc which simply invokes a test function.
• update Makefile accordingly.

Test Plan (dev server):

make db_stress
./db_stress

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[siying]

Is the function defined if gflags isn't installed? If not the public header seems to reference to a function not implemented.

[riversand963]

Looks like this is also the case for db_bench_tool?

[siying]

OK then...

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@riversand963 has imported this pull request. If you are a Facebook employee, you can view this diff on Phabricator.

[facebook-github-bot]

@riversand963 merged this pull request in e60cc09.

[merryChris]

With WITH_TOOLS=ON, errors produces while building db_stress, since db_stress_tool.cc was not included. Even if added, it cannot work fine with db_bench.

[riversand963]

@merryChris. Not very familiar with Cmake. Would you be willing to propose a fix for this?

[merryChris]

@merryChris. Not very familiar with Cmake. Would you be willing to propose a fix for this?

Fine, let me have a try.

[siying]

@riversand963 I think new .cc files need to be added to both of src.md and CMakeList.txt.

[merryChris]

@riversand963 PR as it is. At first, I'd like to fix it by making flags isolation with namespace between db_bench_tool.cc and db_stress_tool.cc, which seems the easiest way. Unfortunately, it doesn't work, plz refer to gfalgs usage. After that, I HAVE TO abstract the common flags to solve flags conflicts. But got confusion while testing with db_stress. Two examples as follows.

Case#1:
./db_stress -prefix_size=0  -allow_concurrent_memtable_write=false

Output:
db_stress: /path/to/db_stress_tool.cc:3387: virtual rocksdb::Status rocksdb::NonBatchedOpsStressTest::TestPrefixScan(rocksdb::{anonymous}::ThreadState*, const rocksdb::ReadOptions&, const std::vector<int>&, const std::vector<long int>&): Assertion `count <= (static_cast<long>(1) << ((8 - FLAGS_prefix_size) * 8))' failed.
Aborted (core dumped)

Case#2
./db_stress -prefix_size=7 -memtablerep=prefix_hash -allow_concurrent_memtable_write=false

Output:
Iterator diverged from control iterator which has value 00000000000FEA36 seek key 00000000000FEAC6
iterator is not valid
Control CF 7
2019/11/27-14:00:00  Starting verification
Stress Test : 26.809 micros/op 37301 ops/sec
            : Wrote 0.03 MB (0.27 MB/sec) (46% of 4110 ops)
            : Wrote 1894 times
            : Deleted 611 times
            : Single deleted 0 times
            : 392 read and 0 found the key
            : Prefix scanned 806 times
            : Iterator size sum is 22
            : Iterated 690 times
            : Deleted 0 key-ranges
            : Range deletions covered 0 keys
            : Got errors 1 times
            : 0 CompactFiles() succeed
            : 0 CompactFiles() did not succeed
Verification failed :(

To be honest, I have to admit that I'm not familiar some flags. Could you plz give me a hand? At the same time, remind to review the PR. Thx in advance.