Add more black-box tests for PlainTable and explicitly support total order mode

Summary:
1. Add some more implementation-aware tests for PlainTable
2. move from a hard-coded one index per 16 rows in one prefix to a configurable number. Also, make hash table ratio = 0  means binary search only. Also fixes some divide 0 risks.
3. Explicitly support total order (only use binary search)
4. some code cleaning up.

Test Plan: make all check

Reviewers: haobo, kailiu

Reviewed By: haobo

CC: leveldb

Differential Revision: https://reviews.facebook.net/D16023
This commit is contained in:
Siying Dong
2014-02-07 16:25:38 -08:00
committed by sdong
parent e6b3e3b4db
commit f3ae3d07cc
8 changed files with 831 additions and 218 deletions

View File

@@ -60,20 +60,44 @@ struct BlockBasedTableOptions {
extern TableFactory* NewBlockBasedTableFactory(
const BlockBasedTableOptions& table_options = BlockBasedTableOptions());
// -- Plain Table with prefix-only seek
// For this factory, you need to set Options.prefix_extrator properly to make it
// work. Look-up will starts with prefix hash lookup for key prefix. Inside the
// hash bucket found, a binary search is executed for hash conflicts. Finally,
// a linear search is used.
// @user_key_len: plain table has optimization for fix-sized keys, which can be
// specified via user_key_len. Alternatively, you can pass
// `kPlainTableVariableLength` if your keys have variable
// lengths.
// @bloom_bits_per_key: the number of bits used for bloom filer per prefix. You
// may disable it by passing a zero.
// @hash_table_ratio: the desired utilization of the hash table used for prefix
// hashing. hash_table_ratio = number of prefixes / #buckets
// in the hash table
// @index_sparseness: inside each prefix, need to build one index record for how
// many keys for binary search inside each hash bucket.
const uint32_t kPlainTableVariableLength = 0;
extern TableFactory* NewPlainTableFactory(uint32_t user_key_len =
kPlainTableVariableLength,
int bloom_bits_per_prefix = 10,
double hash_table_ratio = 0.75,
size_t index_sparseness = 16);
// -- Plain Table
// This factory of plain table ignores Options.prefix_extractor and assumes no
// hashable prefix available to the key structure. Lookup will be based on
// binary search index only. Total order seek() can be issued.
// @user_key_len: plain table has optimization for fix-sized keys, which can be
// specified via user_key_len. Alternatively, you can pass
// `kPlainTableVariableLength` if your keys have variable
// lengths.
// @bloom_bits_per_key: the number of bits used for bloom filer per key. You may
// disable it by passing a zero.
// @hash_table_ratio: the desired utilization of the hash table used for prefix
// hashing. hash_table_ratio = number of prefixes / #buckets
// in the hash table
const uint32_t kPlainTableVariableLength = 0;
extern TableFactory* NewPlainTableFactory(
// @index_sparseness: need to build one index record for how many keys for
// binary search.
extern TableFactory* NewTotalOrderPlainTableFactory(
uint32_t user_key_len = kPlainTableVariableLength,
int bloom_bits_per_key = 10, double hash_table_ratio = 0.75);
int bloom_bits_per_key = 0, size_t index_sparseness = 16);
// A base class for table factories.
class TableFactory {