log: fix how stats are counted

lib/log/index.js

@@ -120,7 +120,7 @@ function Log(filename, opts) {
   let latestBlockIndex = /** @type {number | null} */ (null)
   let nextOffsetInBlock = /** @type {number | null} */ (null)
   let deletedBytes = 0
-  const since = Obv() // offset of last written record
+  const lastRecOffset = Obv() // offset of last written record
 
   let compacting = false
   const compactionProgress = Obv()
@@ -160,14 +160,15 @@ function Log(filename, opts) {
             latestBlockIndex = 0
             nextOffsetInBlock = 0
             cache.set(0, latestBlockBuf)
-            since.set(-1)
+            lastRecOffset.set(-1)
             // @ts-ignore
             while (waitingLoad.length) waitingLoad.shift()()
           } else {
             const blockStart = fileSize - blockSize
             loadLatestBlock(blockStart, function onLoadedLatestBlock(err) {
               if (err) throw err
-              debug('Opened log file, since: %d', since.value)
+              // prettier-ignore
+              debug('Opened log file, last record is at log offset %d', lastRecOffset.value)
               compact(function doneCompactingOnStartup(err) {
                 if (err) debug('Failed compacting on startup: %s', err.message)
                 // @ts-ignore
@@ -201,7 +202,7 @@ function Log(filename, opts) {
               latestBlockIndex = blockStart / blockSize
               const recSize = Record.readSize(blockBuf, offsetInBlock)
               nextOffsetInBlock = offsetInBlock + recSize
-              since.set(blockStart + offsetInBlock)
+              lastRecOffset.set(blockStart + offsetInBlock)
               cb()
             }
           )
@@ -380,7 +381,7 @@ function Log(filename, opts) {
 
     let nextOffset
     if (Record.isEOB(blockBuf, nextOffsetInBlock)) {
-      if (getNextBlockStart(offset) > since.value) nextOffset = -1
+      if (getNextBlockStart(offset) > lastRecOffset.value) nextOffset = -1
       else nextOffset = 0
     } else {
       nextOffset = offset + recSize
@@ -601,7 +602,7 @@ function Log(filename, opts) {
         debug('Failed to write block at log offset %d', blockStart)
         throw err
       } else {
-        since.set(offset)
+        lastRecOffset.set(offset)
 
         // prettier-ignore
         if (drainsBefore.length > 0) debug('Draining the waiting queue (%d functions) for the block at log offset %d', drainsBefore.length, blockStart)
@@ -663,18 +664,22 @@ function Log(filename, opts) {
     })
   }
 
+  function getTotalBytes() {
+    assert(typeof latestBlockIndex === 'number', 'latestBlockIndex not set')
+    assert(typeof nextOffsetInBlock === 'number', 'nextOffsetInBlock not set')
+    return latestBlockIndex * blockSize + nextOffsetInBlock
+  }
+
   /**
    * @param {CB<{ totalBytes: number; deletedBytes: number }>} cb
    */
   function stats(cb) {
-    if (since.value == null) {
-      since((/** @type {number} */ totalBytes) => {
-        cb(null, { totalBytes: Math.max(0, totalBytes), deletedBytes })
-        return false
+    onLoad(() => {
+      cb(null, {
+        totalBytes: getTotalBytes(),
+        deletedBytes,
       })
-    } else {
-      cb(null, { totalBytes: Math.max(0, since.value), deletedBytes })
-    }
+    })()
   }
 
   /**
@@ -751,19 +756,20 @@ function Log(filename, opts) {
     }
 
     // Scan the old log and write blocks on the new log
+    const oldTotalBytes = getTotalBytes()
+    const oldLastRecOffset = lastRecOffset.value
     let latestBlockBufNew = b4a.alloc(blockSize)
     let latestBlockIndexNew = 0
     let nextOffsetInBlockNew = 0
     let holesFound = 0
     let timestampLastEmit = Date.now()
-    const oldLogSize = since.value
     const err3 = await new Promise((done) => {
       scan(
-        function compactScanningRecord(oldOffset, data, size) {
+        function compactScanningRecord(oldRecOffset, data, size) {
           const now = Date.now()
           if (now - timestampLastEmit > COMPACTION_PROGRESS_EMIT_INTERVAL) {
             timestampLastEmit = now
-            const percent = oldOffset / oldLogSize
+            const percent = oldRecOffset / oldLastRecOffset
             compactionProgress.set({ percent, done: false })
           }
           if (!data) {
@@ -825,8 +831,8 @@ function Log(filename, opts) {
     nextOffsetInBlock = nextOffsetInBlockNew
     cache.clear()
     const nextSince = latestBlockIndex * blockSize + nextOffsetInBlock
-    const sizeDiff = oldLogSize - nextSince
-    since.set(nextSince)
+    const sizeDiff = oldTotalBytes - getTotalBytes()
+    lastRecOffset.set(nextSince)
     compacting = false
     deletedBytes = 0
     saveStats(function onSavedStatsAfterCompaction(err) {
@@ -907,7 +913,7 @@ function Log(filename, opts) {
     onOverwritesFlushed: onLoad(onOverwritesFlushed),
     compact: onLoad(compact), // TODO
     compactionProgress,
-    since,
+    lastRecOffset,
     stats, // TODO
 
     // Useful for tests

test/add.test.js

@@ -50,7 +50,7 @@ test('add()', async (t) => {
 
   await p(peer.db._getLog().onDrain)()
   const stats = await p(peer.db.logStats)()
-  assert.deepEqual(stats, { totalBytes: 943, deletedBytes: 0 })
+  assert.deepEqual(stats, { totalBytes: 1450, deletedBytes: 0 })
 
   await p(peer.close)(true)
 })

test/log/basic.test.js

@@ -66,7 +66,7 @@ test('Log basics', async function (t) {
     })
 
     await p(log.onDrain)()
-    assert.equal(log.since.value, 22)
+    assert.equal(log.lastRecOffset.value, 22)
 
     const rec1 = await p(log._get)(0)
     assert.deepEqual(rec1, json1)

test/log/compact.test.js

@@ -21,7 +21,7 @@ test('Log compaction', async (t) => {
     assert('append two records')
 
     const stats2 = await p(log.stats)()
-    assert.equal(stats2.totalBytes, 15, 'stats.totalBytes (2)')
+    assert.equal(stats2.totalBytes, 25, 'stats.totalBytes (2)')
     assert.equal(stats2.deletedBytes, 0, 'stats.deletedBytes (2)')
 
     const progressArr = []
@@ -41,6 +41,10 @@ test('Log compaction', async (t) => {
       'progress events'
     )
 
+    const stats3 = await p(log.stats)()
+    assert.equal(stats3.totalBytes, 25, 'stats.totalBytes (3)')
+    assert.equal(stats3.deletedBytes, 0, 'stats.deletedBytes (3)')
+
     await new Promise((resolve, reject) => {
       const arr = []
       log.scan(
@@ -75,6 +79,10 @@ test('Log compaction', async (t) => {
     await p(log.onDrain)()
     assert('append two records')
 
+    const stats1 = await p(log.stats)()
+    assert.equal(stats1.totalBytes, 25, 'stats.totalBytes before')
+    assert.equal(stats1.deletedBytes, 0, 'stats.deletedBytes before')
+
     await p(log.del)(offset1)
     await p(log.onOverwritesFlushed)()
     assert('delete first record')
@@ -86,11 +94,15 @@ test('Log compaction', async (t) => {
       progressArr,
       [
         { percent: 0, done: false },
-        { percent: 1, done: true, sizeDiff: 5, holesFound: 1 },
+        { percent: 1, done: true, sizeDiff: 15, holesFound: 1 },
       ],
       'progress events'
     )
 
+    const stats2 = await p(log.stats)()
+    assert.equal(stats2.totalBytes, 10, 'stats.totalBytes after')
+    assert.equal(stats2.deletedBytes, 0, 'stats.deletedBytes after')
+
     await new Promise((resolve, reject) => {
       const arr = []
       log.scan(