Batch remote bitfield index refreshes

lib/remote-bitfield.js

@@ -51,11 +51,16 @@ class RemoteBitfieldPage {
 
   insert(start, bitfield) {
     this.bitfield.set(bitfield, start / 32)
-    this.segment.refresh()
   }
 
   clear(start, bitfield) {
     quickbit.clear(this.bitfield, { field: bitfield, offset: start })
+
+    // The sparse index is chunked in 128-bit ranges, so update the chunks touched by this clear.
+    let i = Math.floor(start / 128)
+    const n = i + Math.ceil((bitfield.byteLength * 8) / 128)
+
+    while (i <= n) this.tree.update(this.offset * 8 + i++ * 128)
   }
 }
 
@@ -283,6 +288,7 @@ module.exports = class RemoteBitfield {
 
     let j = start & (BITS_PER_PAGE - 1)
     let i = (start - j) / BITS_PER_PAGE
+    const refresh = new Set()
 
     while (length > 0) {
       let p = this._pages.get(i)
@@ -299,6 +305,7 @@ module.exports = class RemoteBitfield {
       const range = end - j
 
       p.insert(j, bitfield.subarray(0, range / 32))
+      refresh.add(p.segment)
 
       bitfield = bitfield.subarray(range / 32)
 
@@ -307,6 +314,8 @@ module.exports = class RemoteBitfield {
       length -= range
     }
 
+    for (const segment of refresh) segment.refresh()
+
     return true
   }
 

test/remote-bitfield.js

@@ -1,5 +1,6 @@
 const test = require('brittle')
 const b4a = require('b4a')
+const quickbit = require('../lib/compat').quickbit
 const RemoteBitfield = require('../lib/remote-bitfield')
 const { create, replicate } = require('./helpers')
 
@@ -27,6 +28,47 @@ test('remote bitfield - set range to false', function (t) {
   t.is(b.findFirst(true, 0), -1)
 })
 
+test('remote bitfield - batch refreshes insert indexes once per segment', function (t) {
+  const from = quickbit.Index.from
+  let sparseIndexes = 0
+
+  quickbit.Index.from = function (fieldOrChunks, byteLength) {
+    if (Array.isArray(fieldOrChunks)) sparseIndexes++
+    return from.call(this, fieldOrChunks, byteLength)
+  }
+
+  t.teardown(function () {
+    quickbit.Index.from = from
+  })
+
+  const b = new RemoteBitfield()
+  const bitfield = new Uint32Array(RemoteBitfield.BITS_PER_SEGMENT / 32)
+  bitfield.fill(0xffffffff)
+
+  b.insert(0, bitfield)
+
+  t.is(sparseIndexes, 2) // one segment init, one refresh
+  t.is(b.findFirst(true, 0), 0)
+  t.is(b.findFirst(false, 0), RemoteBitfield.BITS_PER_SEGMENT)
+})
+
+test('remote bitfield - clear refreshes indexes for firstUnset', function (t) {
+  const b = new RemoteBitfield()
+  const bitfield = new Uint32Array(RemoteBitfield.BITS_PER_PAGE / 32)
+  bitfield.fill(0xffffffff)
+
+  b.insert(0, bitfield)
+
+  const half = new Uint32Array(RemoteBitfield.BITS_PER_PAGE / 32)
+  half.fill(0xffffffff, 0, half.length / 2)
+
+  b.clear(0, half)
+
+  t.is(b.get(0), false)
+  t.is(b.findFirst(false, 0), 0)
+  t.is(b.findFirst(true, 0), RemoteBitfield.BITS_PER_PAGE / 2)
+})
+
 test('set last bits in segment and findFirst', function (t) {
   const b = new RemoteBitfield()