github-repos/leveldb
1
0
Fork 0
mirror of https://github.com/google/leveldb.git synced 2026-08-22 10:53:27 +08:00
Code Issues Packages Projects Releases Wiki Activity

LevelDB now attempts to reuse the preceding MANIFEST and log file when re-opened.

Browse Source 
(Based on a suggestion by cmumford.)

"open" benchmark on my workstation speeds up significantly since we
can now avoid three fdatasync calls and a compaction per open:

  Before: ~80000 microseconds
  After:    ~130 microseconds

Details:

(1) Added Options::reuse_logs (currently defaults to false) to control
new behavior.  The intention is to change the default to true after some
baking.

(2) Added Env::NewAppendableFile() whose default implementation returns
a not-supported error.

(3) VersionSet::Recovery attempts to reuse the MANIFEST from which
it is recovering.

(4) DBImpl recovery attempts to reuse the last log file and memtable.

(5) db_test.cc now tests a new configuration that sets reuse_logs to true.

(6) fault_injection_test also tests a reuse_logs==true config.

(7) Added a new recovery_test.
This commit is contained in:
Sanjay Ghemawat
2014-12-11 08:13:18 -08:00
committed by Chris Mumford
parent 77948e7eec
commit ac1d69da31
22 changed files with 707 additions and 155 deletions
Download Patch File Download Diff File Expand all files Collapse all files

17
db/log_writer.cc
View File

@@ -12,13 +12,22 @@
namespace leveldb {
namespace log {
static void InitTypeCrc(uint32_t* type_crc) {
for (int i = 0; i <= kMaxRecordType; i++) {
char t = static_cast<char>(i);
type_crc[i] = crc32c::Value(&t, 1);
}
}
Writer::Writer(WritableFile* dest)
: dest_(dest),
block_offset_(0) {
for (int i = 0; i <= kMaxRecordType; i++) {
char t = static_cast<char>(i);
type_crc_[i] = crc32c::Value(&t, 1);
}
InitTypeCrc(type_crc_);
}
Writer::Writer(WritableFile* dest, uint64_t dest_length)
: dest_(dest), block_offset_(dest_length % kBlockSize) {
InitTypeCrc(type_crc_);
}
Writer::~Writer() {