Support fetching sst files metadata, delete files in range, get mem usage (#446)

src/db.rs

@@ -15,7 +15,7 @@
 
 use crate::{
     ffi,
-    ffi_util::{opt_bytes_to_ptr, to_cpath},
+    ffi_util::{from_cstr, opt_bytes_to_ptr, raw_data, to_cpath},
     ColumnFamily, ColumnFamilyDescriptor, CompactOptions, DBIterator, DBPinnableSlice,
     DBRawIterator, DBWALIterator, Direction, Error, FlushOptions, IngestExternalFileOptions,
     IteratorMode, Options, ReadOptions, Snapshot, WriteBatch, WriteOptions,
@@ -1270,6 +1270,97 @@ impl DB {
             Ok(())
         }
     }
+
+    /// Returns a list of all table files with their level, start key
+    /// and end key
+    pub fn live_files(&self) -> Result<Vec<LiveFile>, Error> {
+        unsafe {
+            let files = ffi::rocksdb_livefiles(self.inner);
+            if files.is_null() {
+                Err(Error::new("Could not get live files".to_owned()))
+            } else {
+                let n = ffi::rocksdb_livefiles_count(files);
+
+                let mut livefiles = Vec::with_capacity(n as usize);
+                let mut key_size: usize = 0;
+
+                for i in 0..n {
+                    let name = from_cstr(ffi::rocksdb_livefiles_name(files, i));
+                    let size = ffi::rocksdb_livefiles_size(files, i);
+                    let level = ffi::rocksdb_livefiles_level(files, i) as i32;
+
+                    // get smallest key inside file
+                    let smallest_key = ffi::rocksdb_livefiles_smallestkey(files, i, &mut key_size);
+                    let smallest_key = raw_data(smallest_key, key_size);
+
+                    // get largest key inside file
+                    let largest_key = ffi::rocksdb_livefiles_largestkey(files, i, &mut key_size);
+                    let largest_key = raw_data(largest_key, key_size);
+
+                    livefiles.push(LiveFile {
+                        name,
+                        size,
+                        level,
+                        start_key: smallest_key,
+                        end_key: largest_key,
+                        num_entries: ffi::rocksdb_livefiles_entries(files, i),
+                        num_deletions: ffi::rocksdb_livefiles_deletions(files, i),
+                    })
+                }
+
+                // destroy livefiles metadata(s)
+                ffi::rocksdb_livefiles_destroy(files);
+
+                // return
+                Ok(livefiles)
+            }
+        }
+    }
+
+    /// Delete sst files whose keys are entirely in the given range.
+    ///
+    /// Could leave some keys in the range which are in files which are not
+    /// entirely in the range.
+    ///
+    /// Note: L0 files are left regardless of whether they're in the range.
+    ///  
+    /// Snapshots before the delete might not see the data in the given range.
+    pub fn delete_file_in_range<K: AsRef<[u8]>>(&self, from: K, to: K) -> Result<(), Error> {
+        let from = from.as_ref();
+        let to = to.as_ref();
+        unsafe {
+            ffi_try!(ffi::rocksdb_delete_file_in_range(
+                self.inner,
+                from.as_ptr() as *const c_char,
+                from.len() as size_t,
+                to.as_ptr() as *const c_char,
+                to.len() as size_t,
+            ));
+            Ok(())
+        }
+    }
+
+    /// Same as `delete_file_in_range` but only for specific column family
+    pub fn delete_file_in_range_cf<K: AsRef<[u8]>>(
+        &self,
+        cf: &ColumnFamily,
+        from: K,
+        to: K,
+    ) -> Result<(), Error> {
+        let from = from.as_ref();
+        let to = to.as_ref();
+        unsafe {
+            ffi_try!(ffi::rocksdb_delete_file_in_range_cf(
+                self.inner,
+                cf.inner,
+                from.as_ptr() as *const c_char,
+                from.len() as size_t,
+                to.as_ptr() as *const c_char,
+                to.len() as size_t,
+            ));
+            Ok(())
+        }
+    }
 }
 
 impl Drop for DB {
@@ -1288,3 +1379,22 @@ impl fmt::Debug for DB {
         write!(f, "RocksDB {{ path: {:?} }}", self.path())
     }
 }
+
+/// The metadata that describes a SST file
+#[derive(Debug, Clone)]
+pub struct LiveFile {
+    /// Name of the file
+    pub name: String,
+    /// Size of the file
+    pub size: usize,
+    /// Level at which this file resides
+    pub level: i32,
+    /// Smallest user defined key in the file
+    pub start_key: Option<Vec<u8>>,
+    /// Largest user defined key in the file
+    pub end_key: Option<Vec<u8>>,
+    /// Number of entries/alive keys in the file
+    pub num_entries: u64,
+    /// Number of deletions/tomb key(s) in the file
+    pub num_deletions: u64,
+}

src/db_options.rs

@@ -433,8 +433,8 @@ impl BlockBasedOptions {
         }
     }
 
-    /// Sets the control over blocks (user data is stored in a set of blocks, and
-    /// a block is the unit of reading from disk).
+    /// Sets global cache for blocks (user data is stored in a set of blocks, and
+    /// a block is the unit of reading from disk). Cache must outlive DB instance which uses it.
     ///
     /// If set, use the specified cache for blocks.
     /// By default, rocksdb will automatically create and use an 8MB internal cache.
@@ -444,7 +444,8 @@ impl BlockBasedOptions {
         }
     }
 
-    /// Sets the cache for compressed blocks.
+    /// Sets global cache for compressed blocks. Cache must outlive DB instance which uses it.
+    ///
     /// By default, rocksdb will not use a compressed block cache.
     pub fn set_block_cache_compressed(&mut self, cache: &Cache) {
         unsafe {
@@ -2428,7 +2429,7 @@ impl Options {
         }
     }
 
-    /// Sets global cache for table-level rows.
+    /// Sets global cache for table-level rows. Cache must outlive DB instance which uses it.
     ///
     /// Default: null (disabled)
     /// Not supported in ROCKSDB_LITE mode!
@@ -2591,6 +2592,31 @@ impl Options {
             ffi::rocksdb_options_set_arena_block_size(self.inner, size);
         }
     }
+
+    /// If true, then print malloc stats together with rocksdb.stats when printing to LOG.
+    ///
+    /// Default: false
+    pub fn set_dump_malloc_stats(&mut self, enabled: bool) {
+        unsafe {
+            ffi::rocksdb_options_set_dump_malloc_stats(self.inner, enabled as c_uchar);
+        }
+    }
+
+    /// Enable whole key bloom filter in memtable. Note this will only take effect
+    /// if memtable_prefix_bloom_size_ratio is not 0. Enabling whole key filtering
+    /// can potentially reduce CPU usage for point-look-ups.
+    ///
+    /// Default: false (disable)
+    ///
+    /// Dynamically changeable through SetOptions() API
+    pub fn set_memtable_whole_key_filtering(&mut self, whole_key_filter: bool) {
+        unsafe {
+            ffi::rocksdb_options_set_memtable_whole_key_filtering(
+                self.inner,
+                whole_key_filter as c_uchar,
+            );
+        }
+    }
 }
 
 impl Default for Options {

src/ffi_util.rs

@@ -19,13 +19,28 @@ use std::ffi::{CStr, CString};
 use std::path::Path;
 use std::ptr;
 
+pub(crate) unsafe fn from_cstr(ptr: *const c_char) -> String {
+    let cstr = CStr::from_ptr(ptr as *const _);
+    String::from_utf8_lossy(cstr.to_bytes()).into_owned()
+}
+
+pub(crate) unsafe fn raw_data(ptr: *const c_char, size: usize) -> Option<Vec<u8>> {
+    if ptr.is_null() {
+        None
+    } else {
+        let mut dst = Vec::with_capacity(size);
+        dst.set_len(size);
+        ptr::copy(ptr as *const u8, dst.as_mut_ptr(), size);
+        Some(dst)
+    }
+}
+
 pub fn error_message(ptr: *const c_char) -> String {
-    let cstr = unsafe { CStr::from_ptr(ptr as *const _) };
-    let s = String::from_utf8_lossy(cstr.to_bytes()).into_owned();
     unsafe {
+        let s = from_cstr(ptr);
         libc::free(ptr as *mut c_void);
-    }
         s
+    }
 }
 
 pub fn opt_bytes_to_ptr<T: AsRef<[u8]>>(opt: Option<T>) -> *const c_char {

src/lib.rs

@@ -94,7 +94,7 @@ mod write_batch;
 pub use crate::{
     column_family::{ColumnFamily, ColumnFamilyDescriptor, DEFAULT_COLUMN_FAMILY_NAME},
     compaction_filter::Decision as CompactionDecision,
-    db::DB,
+    db::{LiveFile, DB},
     db_iterator::{DBIterator, DBRawIterator, DBWALIterator, Direction, IteratorMode},
     db_options::{
         BlockBasedIndexType, BlockBasedOptions, BottommostLevelCompaction, Cache, CompactOptions,

src/perf.rs

@@ -12,10 +12,9 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-use libc::{c_char, c_int, c_uchar, c_void};
-use std::ffi::CStr;
+use libc::{c_int, c_uchar, c_void};
 
-use crate::ffi;
+use crate::{ffi, ffi_util::from_cstr, Cache, Error, DB};
 
 #[derive(Debug, Copy, Clone, PartialEq)]
 #[repr(i32)]
@@ -143,15 +142,6 @@ impl Drop for PerfContext {
     }
 }
 
-fn convert(ptr: *const c_char) -> String {
-    let cstr = unsafe { CStr::from_ptr(ptr as *const _) };
-    let s = String::from_utf8_lossy(cstr.to_bytes()).into_owned();
-    unsafe {
-        libc::free(ptr as *mut c_void);
-    }
-    s
-}
-
 impl PerfContext {
     /// Reset context
     pub fn reset(&mut self) {
@@ -163,10 +153,10 @@ impl PerfContext {
     /// Get the report on perf
     pub fn report(&self, exclude_zero_counters: bool) -> String {
         unsafe {
-            convert(ffi::rocksdb_perfcontext_report(
-                self.inner,
-                exclude_zero_counters as c_uchar,
-            ))
+            let ptr = ffi::rocksdb_perfcontext_report(self.inner, exclude_zero_counters as c_uchar);
+            let report = from_cstr(ptr);
+            libc::free(ptr as *mut c_void);
+            report
         }
     }
 
@@ -175,3 +165,121 @@ impl PerfContext {
         unsafe { ffi::rocksdb_perfcontext_metric(self.inner, id as c_int) }
     }
 }
+
+/// Memory usage stats
+pub struct MemoryUsageStats {
+    /// Approximate memory usage of all the mem-tables
+    pub mem_table_total: u64,
+    /// Approximate memory usage of un-flushed mem-tables
+    pub mem_table_unflushed: u64,
+    /// Approximate memory usage of all the table readers
+    pub mem_table_readers_total: u64,
+    /// Approximate memory usage by cache
+    pub cache_total: u64,
+}
+
+/// Wrap over memory_usage_t. Hold current memory usage of the specified DB instances and caches
+struct MemoryUsage {
+    inner: *mut ffi::rocksdb_memory_usage_t,
+}
+
+impl Drop for MemoryUsage {
+    fn drop(&mut self) {
+        unsafe {
+            ffi::rocksdb_approximate_memory_usage_destroy(self.inner);
+        }
+    }
+}
+
+impl MemoryUsage {
+    /// Approximate memory usage of all the mem-tables
+    fn approximate_mem_table_total(&self) -> u64 {
+        unsafe { ffi::rocksdb_approximate_memory_usage_get_mem_table_total(self.inner) }
+    }
+
+    /// Approximate memory usage of un-flushed mem-tables
+    fn approximate_mem_table_unflushed(&self) -> u64 {
+        unsafe { ffi::rocksdb_approximate_memory_usage_get_mem_table_unflushed(self.inner) }
+    }
+
+    /// Approximate memory usage of all the table readers
+    fn approximate_mem_table_readers_total(&self) -> u64 {
+        unsafe { ffi::rocksdb_approximate_memory_usage_get_mem_table_readers_total(self.inner) }
+    }
+
+    /// Approximate memory usage by cache
+    fn approximate_cache_total(&self) -> u64 {
+        unsafe { ffi::rocksdb_approximate_memory_usage_get_cache_total(self.inner) }
+    }
+}
+
+/// Builder for MemoryUsage
+struct MemoryUsageBuilder {
+    inner: *mut ffi::rocksdb_memory_consumers_t,
+}
+
+impl Drop for MemoryUsageBuilder {
+    fn drop(&mut self) {
+        unsafe {
+            ffi::rocksdb_memory_consumers_destroy(self.inner);
+        }
+    }
+}
+
+impl MemoryUsageBuilder {
+    /// Create new instance
+    fn new() -> Result<Self, Error> {
+        let mc = unsafe { ffi::rocksdb_memory_consumers_create() };
+        if mc.is_null() {
+            Err(Error::new(
+                "Could not create MemoryUsage builder".to_owned(),
+            ))
+        } else {
+            Ok(Self { inner: mc })
+        }
+    }
+
+    /// Add a DB instance to collect memory usage from it and add up in total stats
+    fn add_db(&mut self, db: &DB) {
+        unsafe {
+            ffi::rocksdb_memory_consumers_add_db(self.inner, db.inner);
+        }
+    }
+
+    /// Add a cache to collect memory usage from it and add up in total stats
+    fn add_cache(&mut self, cache: &Cache) {
+        unsafe {
+            ffi::rocksdb_memory_consumers_add_cache(self.inner, cache.inner);
+        }
+    }
+
+    /// Build up MemoryUsage
+    fn build(&self) -> Result<MemoryUsage, Error> {
+        unsafe {
+            let mu = ffi_try!(ffi::rocksdb_approximate_memory_usage_create(self.inner));
+            Ok(MemoryUsage { inner: mu })
+        }
+    }
+}
+
+/// Get memory usage stats from DB instances and Cache instances
+pub fn get_memory_usage_stats(
+    dbs: Option<&[&DB]>,
+    caches: Option<&[&Cache]>,
+) -> Result<MemoryUsageStats, Error> {
+    let mut builder = MemoryUsageBuilder::new()?;
+    if let Some(dbs_) = dbs {
+        dbs_.iter().for_each(|db| builder.add_db(db));
+    }
+    if let Some(caches_) = caches {
+        caches_.iter().for_each(|cache| builder.add_cache(cache));
+    }
+
+    let mu = builder.build()?;
+    Ok(MemoryUsageStats {
+        mem_table_total: mu.approximate_mem_table_total(),
+        mem_table_unflushed: mu.approximate_mem_table_unflushed(),
+        mem_table_readers_total: mu.approximate_mem_table_readers_total(),
+        cache_total: mu.approximate_cache_total(),
+    })
+}

tests/test_db.rs

@@ -15,10 +15,10 @@
 mod util;
 
 use rocksdb::{
-    BlockBasedOptions, BottommostLevelCompaction, Cache, CompactOptions, DBCompactionStyle, Env,
-    Error, FifoCompactOptions, IteratorMode, Options, PerfContext, PerfMetric, ReadOptions,
-    SliceTransform, Snapshot, UniversalCompactOptions, UniversalCompactionStopStyle, WriteBatch,
-    DB,
+    perf::get_memory_usage_stats, BlockBasedOptions, BottommostLevelCompaction, Cache,
+    CompactOptions, DBCompactionStyle, Env, Error, FifoCompactOptions, IteratorMode, Options,
+    PerfContext, PerfMetric, ReadOptions, SliceTransform, Snapshot, UniversalCompactOptions,
+    UniversalCompactionStopStyle, WriteBatch, DB,
 };
 use std::sync::Arc;
 use std::time::Duration;
@@ -495,11 +495,13 @@ fn compact_range_test() {
         opts.create_missing_column_families(true);
 
         // set compaction style
+        {
             let mut uni_co_opts = UniversalCompactOptions::default();
             uni_co_opts.set_size_ratio(2);
             uni_co_opts.set_stop_style(UniversalCompactionStopStyle::Total);
             opts.set_compaction_style(DBCompactionStyle::Universal);
             opts.set_universal_compaction_options(&uni_co_opts);
+        }
 
         // set compaction options
         let mut compact_opts = CompactOptions::default();
@@ -540,10 +542,12 @@ fn fifo_compaction_test() {
         opts.create_missing_column_families(true);
 
         // set compaction style
+        {
             let mut fifo_co_opts = FifoCompactOptions::default();
             fifo_co_opts.set_max_table_files_size(4 << 10); // 4KB
             opts.set_compaction_style(DBCompactionStyle::Fifo);
             opts.set_fifo_compaction_options(&fifo_co_opts);
+        }
 
         // put and compact column family cf1
         let cfs = vec!["cf1"];
@@ -560,11 +564,11 @@ fn fifo_compaction_test() {
         let ctx = PerfContext::default();
 
         let block_cache_hit_count = ctx.metric(PerfMetric::BlockCacheHitCount);
-        assert!(block_cache_hit_count > 0);
-
+        if block_cache_hit_count > 0 {
             let expect = format!("block_cache_hit_count = {}", block_cache_hit_count);
             assert!(ctx.report(true).contains(&expect));
         }
+    }
 }
 
 #[test]
@@ -577,14 +581,18 @@ fn env_and_dbpaths_test() {
         opts.create_if_missing(true);
         opts.create_missing_column_families(true);
 
+        {
             let mut env = Env::default().unwrap();
             env.lower_high_priority_thread_pool_cpu_priority();
             opts.set_env(&env);
+        }
 
+        {
             let mut paths = Vec::new();
             paths.push(rocksdb::DBPath::new(&path1, 20 << 20).unwrap());
             paths.push(rocksdb::DBPath::new(&path2, 30 << 20).unwrap());
             opts.set_db_paths(&paths);
+        }
 
         let db = DB::open(&opts, &path).unwrap();
         db.put(b"k1", b"v1").unwrap();
@@ -626,7 +634,7 @@ fn prefix_extract_and_iterate_test() {
 fn get_with_cache_and_bulkload_test() {
     let path = DBPath::new("_rust_rocksdb_get_with_cache_and_bulkload_test");
     let log_path = DBPath::new("_rust_rocksdb_log_path_test");
-    {
+
     // create options
     let mut opts = Options::default();
     opts.create_if_missing(true);
@@ -638,9 +646,17 @@ fn get_with_cache_and_bulkload_test() {
     opts.set_max_subcompactions(2);
     opts.set_max_background_jobs(4);
     opts.set_use_adaptive_mutex(true);
+    opts.set_db_log_dir(&log_path);
+    opts.set_memtable_whole_key_filtering(true);
+    opts.set_dump_malloc_stats(true);
+
+    // trigger all sst files in L1/2 instead of L0
+    opts.set_max_bytes_for_level_base(64 << 10); // 64KB
 
+    {
         // set block based table and cache
-        let cache = Cache::new_lru_cache(64 << 10).unwrap();
+        let cache = Cache::new_lru_cache(512 << 10).unwrap();
+        assert_eq!(cache.get_usage(), 0);
         let mut block_based_opts = BlockBasedOptions::default();
         block_based_opts.set_block_cache(&cache);
         block_based_opts.set_cache_index_and_filter_blocks(true);
@@ -651,29 +667,30 @@ fn get_with_cache_and_bulkload_test() {
 
         // write a lot
         let mut batch = WriteBatch::default();
-        for i in 0..1_000 {
+        for i in 0..10_000 {
             batch.put(format!("{:0>4}", i).as_bytes(), b"v");
         }
         assert!(db.write(batch).is_ok());
 
-        // flush memory table to sst, trigger cache usage on `get`
+        // flush memory table to sst and manual compaction
         assert!(db.flush().is_ok());
+        db.compact_range(Some(format!("{:0>4}", 0).as_bytes()), None::<Vec<u8>>);
 
         // get -> trigger caching
         let _ = db.get(b"1");
         assert!(cache.get_usage() > 0);
+
+        // get approximated memory usage
+        let mem_usage = get_memory_usage_stats(Some(&[&db]), None).unwrap();
+        assert!(mem_usage.mem_table_total > 0);
+
+        // get approximated cache usage
+        let mem_usage = get_memory_usage_stats(None, Some(&[&cache])).unwrap();
+        assert!(mem_usage.cache_total > 0);
     }
 
     // bulk loading
     {
-        // create new options
-        let mut opts = Options::default();
-        opts.set_delete_obsolete_files_period_micros(100_000);
-        opts.prepare_for_bulk_load();
-        opts.set_db_log_dir(&log_path);
-        opts.set_max_sequential_skip_in_iterations(16);
-        opts.set_paranoid_checks(true);
-
         // open db
         let db = DB::open(&opts, &path).unwrap();
 
@@ -682,12 +699,41 @@ fn get_with_cache_and_bulkload_test() {
         for (expected, (k, _)) in iter.enumerate() {
             assert_eq!(k.as_ref(), format!("{:0>4}", expected).as_bytes());
         }
+
+        // check live files (sst files meta)
+        let livefiles = db.live_files().unwrap();
+        assert_eq!(livefiles.len(), 1);
+        livefiles.iter().for_each(|f| {
+            assert_eq!(f.level, 2);
+            assert!(!f.name.is_empty());
+            assert_eq!(
+                f.start_key.as_ref().unwrap().as_slice(),
+                format!("{:0>4}", 0).as_bytes()
+            );
+            assert_eq!(
+                f.end_key.as_ref().unwrap().as_slice(),
+                format!("{:0>4}", 9999).as_bytes()
+            );
+            assert_eq!(f.num_entries, 10000);
+            assert_eq!(f.num_deletions, 0);
+        });
+
+        // delete sst file in range (except L0)
+        assert!(db
+            .delete_file_in_range(
+                format!("{:0>4}", 0).as_bytes(),
+                format!("{:0>4}", 9999).as_bytes()
+            )
+            .is_ok());
+        let livefiles = db.live_files().unwrap();
+        assert_eq!(livefiles.len(), 0);
+
+        // try to get a deleted key
+        assert!(db.get(format!("{:0>4}", 123).as_bytes()).unwrap().is_none());
     }
 
     // raise error when db exists
     {
-        // create new options
-        let mut opts = Options::default();
         opts.set_error_if_exists(true);
         assert!(DB::open(&opts, &path).is_err());
     }