Re: RocksDB Incorrect API Usage

["Piotr Dałek" <branch@predictor.org.pl>]

On Wed, Jun 01, 2016 at 12:49:53AM +0800, Haomai Wang wrote:
> Hi Sage and Mark,
> 
> As mentioned in BlueStore standup, I found rocksdb iterator *Seek*
> won't use bloom filter like *Get*.
> 
> *Get* impl: it will look at filter firstly
> https://github.com/facebook/rocksdb/blob/master/table/block_based_table_reader.cc#L1369
> 
> Iterator *Seek*: it will do binary search, by default we don't specify
> prefix feature(https://github.com/facebook/rocksdb/wiki/Prefix-Seek-API-Changes).
> https://github.com/facebook/rocksdb/blob/master/table/block.cc#L94
> 
> [..]
> --- a/db/db_bench.cc
> +++ b/db/db_bench.cc
> @@ -2923,14 +2923,12 @@ class Benchmark {
>          int64_t key_rand = thread->rand.Next() & (pot - 1);
>          GenerateKeyFromInt(key_rand, FLAGS_num, &key);
>          ++read;
> -        auto status = db->Get(options, key, &value);
> -        if (status.ok()) {
> -          ++found;
> -        } else if (!status.IsNotFound()) {
> -          fprintf(stderr, "Get returned an error: %s\n",
> -                  status.ToString().c_str());
> -          abort();
> -        }
> +        Iterator* iter = db->NewIterator(options);
> +      iter->Seek(key);
> +      if (iter->Valid() && iter->key().compare(key) == 0) {
> +        found++;
> +      }
> +
>          if (key_rand >= FLAGS_num) {
>            ++nonexist;
>          }

Aren't you missing "delete iter" here?

-- 
Piotr Dałek
branch@predictor.org.pl
http://blog.predictor.org.pl
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