ARCHIVE/rippled
1
0
Fork 0
mirror of https://github.com/XRPLF/rippled.git synced 2025-12-06 17:27:55 +00:00
Code Issues Packages Projects Releases Wiki Activity

Fixed cache key for block cache

Browse Source 
Summary:
Added function to `RandomAccessFile` to generate an unique ID for that file. Currently only `PosixRandomAccessFile` has this behaviour implemented and only on Linux.

Changed how key is generated in `Table::BlockReader`.

Added tests to check whether the unique ID is stable, unique and not a prefix of another unique ID. Added tests to see that `Table` uses the cache more efficiently.

Test Plan: make check

Reviewers: chip, vamsi, dhruba

Reviewed By: chip

CC: leveldb

Differential Revision: https://reviews.facebook.net/D8145
This commit is contained in:
Kosie van der Merwe
2013-01-31 15:20:24 -08:00
parent 2c3565285e
commit 4dcc0c89f4
7 changed files with 329 additions and 17 deletions
Download Patch File Download Diff File Expand all files Collapse all files

20
include/leveldb/env.h
View File

@@ -223,6 +223,26 @@ class RandomAccessFile {
// Safe for concurrent use by multiple threads.
virtual Status Read(uint64_t offset, size_t n, Slice* result,
char* scratch) const = 0;
// Tries to get an unique ID for this file that will be the same each time
// the file is opened (and will stay the same while the file is open).
// Furthermore, it tries to make this ID at most "max_size" bytes. If such an
// ID can be created this function returns the length of the ID and places it
// in "id"; otherwise, this function returns 0, in which case "id" may more
// may not have been modified.
//
// This function guarantees, for IDs from a given environment, two unique ids
// cannot be made equal to eachother by adding arbitrary bytes to one of
// them. That is, no unique ID is the prefix of another.
//
// This function guarantees that the returned ID will not be interpretable as
// a single varint.
//
// Note: these IDs are only valid for the duration of the process.
virtual size_t GetUniqueId(char* id, size_t max_size) const {
return 0; // Default implementation to prevent issues with backwards
// compatibility.
};
};
// A file abstraction for sequential writing. The implementation

6
include/leveldb/table.h
View File

@@ -58,6 +58,10 @@ class Table {
// be close to the file length.
uint64_t ApproximateOffsetOf(const Slice& key) const;
// Returns true if the block for the specified key is in cache.
// REQUIRES: key is in this table.
bool TEST_KeyInCache(const ReadOptions& options, const Slice& key);
private:
struct Rep;
Rep* rep_;
@@ -80,6 +84,8 @@ class Table {
void ReadMeta(const Footer& footer);
void ReadFilter(const Slice& filter_handle_value);
static void SetupCacheKeyPrefix(Rep* rep);
// No copying allowed
Table(const Table&);
void operator=(const Table&);