diff --git a/java/res/values/donottranslate.xml b/java/res/values/donottranslate.xml
index 82c5ce4..42e692d 100644
--- a/java/res/values/donottranslate.xml
+++ b/java/res/values/donottranslate.xml
@@ -158,47 +158,47 @@
 
     <!-- Compatibility map from subtypeLocale:subtypeExtraValue to keyboardLayoutSet -->
     <string-array name="locale_and_extra_value_to_keyboard_layout_set_map">
-        <item>en_US:TrySuppressingImeSwitcher,AsciiCapable,SupportTouchPositionCorrection</item>
+        <item>en_US:TrySuppressingImeSwitcher,AsciiCapable,SupportTouchPositionCorrection,EmojiCapable</item>
         <item>qwerty</item>
-        <item>en_GB:TrySuppressingImeSwitcher,AsciiCapable,SupportTouchPositionCorrection</item>
+        <item>en_GB:TrySuppressingImeSwitcher,AsciiCapable,SupportTouchPositionCorrection,EmojiCapable</item>
         <item>qwerty</item>
-        <item>ar:SupportTouchPositionCorrection</item>
+        <item>ar:SupportTouchPositionCorrection,EmojiCapable</item>
         <item>arabic</item>
-        <item>cs:AsciiCapable,SupportTouchPositionCorrection</item>
+        <item>cs:AsciiCapable,SupportTouchPositionCorrection,EmojiCapable</item>
         <item>qwertz</item>
-        <item>da:AsciiCapable,SupportTouchPositionCorrection</item>
+        <item>da:AsciiCapable,SupportTouchPositionCorrection,EmojiCapable</item>
         <item>nordic</item>
-        <item>de:AsciiCapable,SupportTouchPositionCorrection</item>
+        <item>de:AsciiCapable,SupportTouchPositionCorrection,EmojiCapable</item>
         <item>qwertz</item>
-        <item>es:AsciiCapable,SupportTouchPositionCorrection</item>
+        <item>es:AsciiCapable,SupportTouchPositionCorrection,EmojiCapable</item>
         <item>spanish</item>
-        <item>fi:AsciiCapable,SupportTouchPositionCorrection</item>
+        <item>fi:AsciiCapable,SupportTouchPositionCorrection,EmojiCapable</item>
         <item>nordic</item>
-        <item>fr:AsciiCapable,SupportTouchPositionCorrection</item>
+        <item>fr:AsciiCapable,SupportTouchPositionCorrection,EmojiCapable</item>
         <item>azerty</item>
-        <item>fr_CA:AsciiCapable,SupportTouchPositionCorrection</item>
+        <item>fr_CA:AsciiCapable,SupportTouchPositionCorrection,EmojiCapable</item>
         <item>qwerty</item>
-        <item>hr:AsciiCapable,SupportTouchPositionCorrection</item>
+        <item>hr:AsciiCapable,SupportTouchPositionCorrection,EmojiCapable</item>
         <item>qwertz</item>
-        <item>hu:AsciiCapable,SupportTouchPositionCorrection</item>
+        <item>hu:AsciiCapable,SupportTouchPositionCorrection,EmojiCapable</item>
         <item>qwertz</item>
-        <item>it:AsciiCapable,SupportTouchPositionCorrection</item>
+        <item>it:AsciiCapable,SupportTouchPositionCorrection,EmojiCapable</item>
         <item>qwerty</item>
-        <item>iw:SupportTouchPositionCorrection</item>
+        <item>iw:SupportTouchPositionCorrection,EmojiCapable</item>
         <item>hebrew</item>
-        <item>nb:AsciiCapable,SupportTouchPositionCorrection</item>
+        <item>nb:AsciiCapable,SupportTouchPositionCorrection,EmojiCapable</item>
         <item>nordic</item>
-        <item>nl:AsciiCapable,SupportTouchPositionCorrection</item>
+        <item>nl:AsciiCapable,SupportTouchPositionCorrection,EmojiCapable</item>
         <item>qwerty</item>
-        <item>pl:AsciiCapable,SupportTouchPositionCorrection</item>
+        <item>pl:AsciiCapable,SupportTouchPositionCorrection,EmojiCapable</item>
         <item>qwerty</item>
-        <item>ru:SupportTouchPositionCorrection</item>
+        <item>ru:SupportTouchPositionCorrection,EmojiCapable</item>
         <item>east_slavic</item>
-        <item>sr:SupportTouchPositionCorrection</item>
+        <item>sr:SupportTouchPositionCorrection,EmojiCapable</item>
         <item>south_slavic</item>
-        <item>sv:AsciiCapable,SupportTouchPositionCorrection</item>
+        <item>sv:AsciiCapable,SupportTouchPositionCorrection,EmojiCapable</item>
         <item>nordic</item>
-        <item>tr:AsciiCapable,SupportTouchPositionCorrection</item>
+        <item>tr:AsciiCapable,SupportTouchPositionCorrection,EmojiCapable</item>
         <item>qwerty</item>
     </string-array>
 
diff --git a/java/res/xml-sw600dp/row_pcqwerty5.xml b/java/res/xml-sw600dp/row_pcqwerty5.xml
index a79d2a8..b854f10 100644
--- a/java/res/xml-sw600dp/row_pcqwerty5.xml
+++ b/java/res/xml-sw600dp/row_pcqwerty5.xml
@@ -53,7 +53,7 @@
                     latin:keyXPos="-9.0%p"
                     latin:keyWidth="9.0%p"
                     latin:backgroundType="functional"
-                    latin:keyboardLayout="@xml/key_symbols_period" />
+                    latin:keyboardLayout="@xml/key_f2" />
             </default>
         </switch>
     </Row>
diff --git a/java/res/xml/method.xml b/java/res/xml/method.xml
index d7424c0..d92dc29 100644
--- a/java/res/xml/method.xml
+++ b/java/res/xml/method.xml
@@ -62,8 +62,8 @@
     mn: Mongolian/mongolian
     ms: Malay/qwerty
     nb: Norwegian Bokmål/nordic
-    ne: Nepali Romanized/nepali_romanized
-    ne: Nepali Traditional/nepali_traditional
+    ne: Nepali Romanized/nepali_romanized  # disabled temporarily
+    ne: Nepali Traditional/nepali_traditional  # disabled temporarily
     nl: Dutch/qwerty
     nl_BE: Dutch Belgium/azerty
     pl: Polish/qwerty
@@ -380,6 +380,7 @@
             android:imeSubtypeMode="keyboard"
             android:imeSubtypeExtraValue="AsciiCapable,SupportTouchPositionCorrection,EmojiCapable"
     />
+    <!--
     <subtype android:icon="@drawable/ic_subtype_keyboard"
             android:label="@string/subtype_generic"
             android:subtypeId="0xd80a4cee"
@@ -394,6 +395,7 @@
             android:imeSubtypeMode="keyboard"
             android:imeSubtypeExtraValue="KeyboardLayoutSet=nepali_traditional,EmojiCapable"
     />
+    -->
     <subtype android:icon="@drawable/ic_subtype_keyboard"
             android:label="@string/subtype_generic"
             android:subtypeId="0x3f9fd91e"
diff --git a/java/res/xml/row_pcqwerty5.xml b/java/res/xml/row_pcqwerty5.xml
index 0e61805..4ec908b 100644
--- a/java/res/xml/row_pcqwerty5.xml
+++ b/java/res/xml/row_pcqwerty5.xml
@@ -51,13 +51,13 @@
                     latin:keyWidth="11.538%p" />
                 <Key
                     latin:keyStyle="spaceKeyStyle"
-                    latin:keyWidth="42.310%p" />
+                    latin:keyWidth="38.464%p" />
                 </case>
             <!-- languageSwitchKeyEnabled="false" -->
             <default>
                 <Key
                     latin:keyStyle="spaceKeyStyle"
-                    latin:keyWidth="53.848%p" />
+                    latin:keyWidth="50.002%p" />
             </default>
         </switch>
         <Key
@@ -71,9 +71,9 @@
             </case>
             <!-- keyboardLayoutSetElement="alphabetManualShifted|alphabetShiftLocked|alphabetShiftLockShifted" -->
             <default>
-                <include
-                    latin:keyboardLayout="@xml/key_symbols_period"
-                    latin:backgroundType="functional" />
+                <Key
+                    latin:keyStyle="emojiKeyStyle"
+                    latin:keyWidth="fillRight" />
             </default>
         </switch>
     </Row>
diff --git a/java/src/com/android/inputmethod/keyboard/ProximityInfo.java b/java/src/com/android/inputmethod/keyboard/ProximityInfo.java
index cd127c7..a031669 100644
--- a/java/src/com/android/inputmethod/keyboard/ProximityInfo.java
+++ b/java/src/com/android/inputmethod/keyboard/ProximityInfo.java
@@ -245,8 +245,8 @@
         final int threshold = (int) (defaultWidth * SEARCH_DISTANCE);
         final int thresholdSquared = threshold * threshold;
         // Round-up so we don't have any pixels outside the grid
-        final int fullGridWidth = mGridWidth * mCellWidth;
-        final int fullGridHeight = mGridHeight * mCellHeight;
+        final int lastPixelXCoordinate = mGridWidth * mCellWidth - 1;
+        final int lastPixelYCoordinate = mGridHeight * mCellHeight - 1;
 
         // For large layouts, 'neighborsFlatBuffer' is about 80k of memory: gridSize is usually 512,
         // keycount is about 40 and a pointer to a Key is 4 bytes. This contains, for each cell,
@@ -329,22 +329,20 @@
             final int yMiddleOfTopCell = topPixelWithinThreshold - yDeltaToGrid + halfCellHeight;
             final int yStart = Math.max(halfCellHeight,
                     yMiddleOfTopCell + (yDeltaToGrid <= halfCellHeight ? 0 : mCellHeight));
-            final int yEnd = Math.min(fullGridHeight, keyY + key.getHeight() + threshold);
+            final int yEnd = Math.min(lastPixelYCoordinate, keyY + key.getHeight() + threshold);
 
             final int leftPixelWithinThreshold = keyX - threshold;
             final int xDeltaToGrid = leftPixelWithinThreshold % mCellWidth;
             final int xMiddleOfLeftCell = leftPixelWithinThreshold - xDeltaToGrid + halfCellWidth;
             final int xStart = Math.max(halfCellWidth,
                     xMiddleOfLeftCell + (xDeltaToGrid <= halfCellWidth ? 0 : mCellWidth));
-            final int xEnd = Math.min(fullGridWidth, keyX + key.getWidth() + threshold);
+            final int xEnd = Math.min(lastPixelXCoordinate, keyX + key.getWidth() + threshold);
 
             int baseIndexOfCurrentRow = (yStart / mCellHeight) * mGridWidth + (xStart / mCellWidth);
             for (int centerY = yStart; centerY <= yEnd; centerY += mCellHeight) {
                 int index = baseIndexOfCurrentRow;
                 for (int centerX = xStart; centerX <= xEnd; centerX += mCellWidth) {
-                    // TODO: Remove "index < neighborCountPerCell.length" below.
-                    if (index < neighborCountPerCell.length
-                            && key.squaredDistanceToEdge(centerX, centerY) < thresholdSquared) {
+                    if (key.squaredDistanceToEdge(centerX, centerY) < thresholdSquared) {
                         neighborsFlatBuffer[index * keyCount + neighborCountPerCell[index]] = key;
                         ++neighborCountPerCell[index];
                     }
diff --git a/java/src/com/android/inputmethod/latin/ExpandableBinaryDictionary.java b/java/src/com/android/inputmethod/latin/ExpandableBinaryDictionary.java
index 2a90764..fcd7ede 100644
--- a/java/src/com/android/inputmethod/latin/ExpandableBinaryDictionary.java
+++ b/java/src/com/android/inputmethod/latin/ExpandableBinaryDictionary.java
@@ -311,9 +311,10 @@
     }
 
     @Override
-    public ArrayList<SuggestedWordInfo> getSuggestions(final WordComposer composer,
+    public ArrayList<SuggestedWordInfo> getSuggestionsWithSessionId(final WordComposer composer,
             final String prevWord, final ProximityInfo proximityInfo,
-            final boolean blockOffensiveWords, final int[] additionalFeaturesOptions) {
+            final boolean blockOffensiveWords, final int[] additionalFeaturesOptions,
+            final int sessionId) {
         reloadDictionaryIfRequired();
         final ArrayList<SuggestedWordInfo> suggestions = CollectionUtils.newArrayList();
         final AsyncResultHolder<ArrayList<SuggestedWordInfo>> holder =
@@ -321,14 +322,16 @@
         getExecutor(mFilename).executePrioritized(new Runnable() {
             @Override
             public void run() {
-                final ArrayList<SuggestedWordInfo> inMemDictSuggestion =
-                        mDictionaryWriter.getSuggestions(composer, prevWord, proximityInfo,
-                                blockOffensiveWords, additionalFeaturesOptions);
+                final ArrayList<SuggestedWordInfo> inMemDictSuggestion = composer.isBatchMode() ?
+                        null : mDictionaryWriter.getSuggestionsWithSessionId(composer, prevWord,
+                                proximityInfo, blockOffensiveWords, additionalFeaturesOptions,
+                                sessionId);
                 // TODO: Remove checking mIsUpdatable and use native suggestion.
                 if (mBinaryDictionary != null && !mIsUpdatable) {
                     final ArrayList<SuggestedWordInfo> binarySuggestion =
-                            mBinaryDictionary.getSuggestions(composer, prevWord, proximityInfo,
-                                    blockOffensiveWords, additionalFeaturesOptions);
+                            mBinaryDictionary.getSuggestionsWithSessionId(composer, prevWord,
+                                    proximityInfo, blockOffensiveWords, additionalFeaturesOptions,
+                                    sessionId);
                     if (inMemDictSuggestion == null) {
                         holder.set(binarySuggestion);
                     } else if (binarySuggestion == null) {
@@ -342,11 +345,18 @@
                 }
             }
         });
-
         return holder.get(null, TIMEOUT_FOR_READ_OPS_IN_MILLISECONDS);
     }
 
     @Override
+    public ArrayList<SuggestedWordInfo> getSuggestions(final WordComposer composer,
+            final String prevWord, final ProximityInfo proximityInfo,
+            final boolean blockOffensiveWords, final int[] additionalFeaturesOptions) {
+        return getSuggestionsWithSessionId(composer, prevWord, proximityInfo, blockOffensiveWords,
+                additionalFeaturesOptions, 0 /* sessionId */);
+    }
+
+    @Override
     public boolean isValidWord(final String word) {
         reloadDictionaryIfRequired();
         return isValidWordInner(word);
diff --git a/java/src/com/android/inputmethod/latin/Suggest.java b/java/src/com/android/inputmethod/latin/Suggest.java
index 1684d47..6c18c94 100644
--- a/java/src/com/android/inputmethod/latin/Suggest.java
+++ b/java/src/com/android/inputmethod/latin/Suggest.java
@@ -361,12 +361,6 @@
 
         // At second character typed, search the unigrams (scores being affected by bigrams)
         for (final String key : mDictionaries.keySet()) {
-            // Skip User history dictionary for lookup
-            // TODO: The user history dictionary should just override getSuggestionsWithSessionId
-            // to make sure it doesn't return anything and we should remove this test
-            if (key.equals(Dictionary.TYPE_USER_HISTORY)) {
-                continue;
-            }
             final Dictionary dictionary = mDictionaries.get(key);
             suggestionsSet.addAll(dictionary.getSuggestionsWithSessionId(wordComposer,
                     prevWordForBigram, proximityInfo, blockOffensiveWords,
diff --git a/native/jni/src/suggest/policyimpl/dictionary/bigram/bigram_list_read_write_utils.h b/native/jni/src/suggest/policyimpl/dictionary/bigram/bigram_list_read_write_utils.h
index 884bcd7..9092a80 100644
--- a/native/jni/src/suggest/policyimpl/dictionary/bigram/bigram_list_read_write_utils.h
+++ b/native/jni/src/suggest/policyimpl/dictionary/bigram/bigram_list_read_write_utils.h
@@ -98,6 +98,13 @@
            flags |= FLAG_ATTRIBUTE_ADDRESS_TYPE_ONEBYTE;
            *outOffsetFieldSize = 1;
        }
+
+       // Currently, all newly written bigram position fields are 3 bytes to simplify dictionary
+       // writing.
+       // TODO: Remove following 2 lines and optimize memory space.
+       flags = (flags & (~MASK_ATTRIBUTE_ADDRESS_TYPE)) | FLAG_ATTRIBUTE_ADDRESS_TYPE_THREEBYTES;
+       *outOffsetFieldSize = 3;
+
        *outBigramFlags = flags;
        *outOffset = absOffest;
        return true;
diff --git a/native/jni/src/suggest/policyimpl/dictionary/bigram/dynamic_bigram_list_policy.cpp b/native/jni/src/suggest/policyimpl/dictionary/bigram/dynamic_bigram_list_policy.cpp
index 4c44d22..bd58b99 100644
--- a/native/jni/src/suggest/policyimpl/dictionary/bigram/dynamic_bigram_list_policy.cpp
+++ b/native/jni/src/suggest/policyimpl/dictionary/bigram/dynamic_bigram_list_policy.cpp
@@ -54,8 +54,8 @@
     }
 }
 
-bool DynamicBigramListPolicy::copyAllBigrams(int *const fromPos, int *const toPos,
-        int *outBigramsCount) {
+bool DynamicBigramListPolicy::copyAllBigrams(BufferWithExtendableBuffer *const bufferToWrite,
+        int *const fromPos, int *const toPos, int *const outBigramsCount) const {
     const bool usesAdditionalBuffer = mBuffer->isInAdditionalBuffer(*fromPos);
     if (usesAdditionalBuffer) {
         *fromPos -= mBuffer->getOriginalBufferSize();
@@ -86,10 +86,10 @@
             continue;
         }
         // Write bigram entry. Target buffer is always the additional buffer.
-        if (!mBuffer->writeUintAndAdvancePosition(newBigramFlags, 1 /* size */,toPos)) {
+        if (!bufferToWrite->writeUintAndAdvancePosition(newBigramFlags, 1 /* size */,toPos)) {
             return false;
         }
-        if (!mBuffer->writeUintAndAdvancePosition(newBigramOffset, newBigramOffsetFieldSize,
+        if (!bufferToWrite->writeUintAndAdvancePosition(newBigramOffset, newBigramOffsetFieldSize,
                 toPos)) {
             return false;
         }
diff --git a/native/jni/src/suggest/policyimpl/dictionary/bigram/dynamic_bigram_list_policy.h b/native/jni/src/suggest/policyimpl/dictionary/bigram/dynamic_bigram_list_policy.h
index dafb62d..5d02d32 100644
--- a/native/jni/src/suggest/policyimpl/dictionary/bigram/dynamic_bigram_list_policy.h
+++ b/native/jni/src/suggest/policyimpl/dictionary/bigram/dynamic_bigram_list_policy.h
@@ -44,10 +44,11 @@
 
     void skipAllBigrams(int *const pos) const;
 
-    // Copy bigrams from the bigram list that starts at fromPos to toPos and advance these
-    // positions after bigram lists. This method skips invalid bigram entries and write the valid
-    // bigram entry count to outBigramsCount.
-    bool copyAllBigrams(int *const fromPos, int *const toPos, int *outBigramsCount);
+    // Copy bigrams from the bigram list that starts at fromPos in mBuffer to toPos in
+    // bufferToWrite and advance these positions after bigram lists. This method skips invalid
+    // bigram entries and write the valid bigram entry count to outBigramsCount.
+    bool copyAllBigrams(BufferWithExtendableBuffer *const bufferToWrite, int *const fromPos,
+            int *const toPos, int *const outBigramsCount) const;
 
     bool addNewBigramEntryToBigramList(const int bigramPos, const int probability, int *const pos);
 
diff --git a/native/jni/src/suggest/policyimpl/dictionary/dynamic_patricia_trie_writing_helper.cpp b/native/jni/src/suggest/policyimpl/dictionary/dynamic_patricia_trie_writing_helper.cpp
index 31178fb..f4c98d8 100644
--- a/native/jni/src/suggest/policyimpl/dictionary/dynamic_patricia_trie_writing_helper.cpp
+++ b/native/jni/src/suggest/policyimpl/dictionary/dynamic_patricia_trie_writing_helper.cpp
@@ -97,8 +97,8 @@
         return false;
     }
     int writingPos = newNodePos;
-    // Write a new PtNode using original PtNode's info to the tail of the dictionary.
-    if (!writePtNodeToBufferByCopyingPtNodeInfo(&nodeReader, nodeReader.getParentPos(),
+    // Write a new PtNode using original PtNode's info to the tail of the dictionary in mBuffer.
+    if (!writePtNodeToBufferByCopyingPtNodeInfo(mBuffer, &nodeReader, nodeReader.getParentPos(),
             mMergedNodeCodePoints, nodeReader.getCodePointCount(), nodeReader.getProbability(),
             &writingPos)) {
         return false;
@@ -143,38 +143,20 @@
     if (!headerPolicy->writeHeaderToBuffer(&headerBuffer, false /* updatesLastUpdatedTime */)) {
         return;
     }
-    const int tmpFileNameBufSize = strlen(fileName)
-            + strlen(TEMP_FILE_SUFFIX_FOR_WRITING_DICT_FILE) + 1;
-    char tmpFileName[tmpFileNameBufSize];
-    snprintf(tmpFileName, tmpFileNameBufSize, "%s%s", fileName,
-            TEMP_FILE_SUFFIX_FOR_WRITING_DICT_FILE);
-    FILE *const file = fopen(tmpFileName, "wb");
-    if (!file) {
+    flushAllToFile(fileName, &headerBuffer, mBuffer);
+}
+
+void DynamicPatriciaTrieWritingHelper::writeToDictFileWithGC(const int rootPtNodeArrayPos,
+        const char *const fileName, const HeaderPolicy *const headerPolicy) {
+    BufferWithExtendableBuffer headerBuffer(0 /* originalBuffer */, 0 /* originalBufferSize */);
+    if (!headerPolicy->writeHeaderToBuffer(&headerBuffer, true /* updatesLastUpdatedTime */)) {
         return;
     }
-    // Write header.
-    if (fwrite(headerBuffer.getBuffer(true /* usesAdditionalBuffer */),
-            headerBuffer.getTailPosition(), 1, file) < 1) {
-        fclose(file);
-        remove(tmpFileName);
+    BufferWithExtendableBuffer newDictBuffer(0 /* originalBuffer */, 0 /* originalBufferSize */);
+    if (!runGC(rootPtNodeArrayPos, &newDictBuffer)) {
         return;
     }
-    // Write data in original buffer.
-    if (fwrite(mBuffer->getBuffer(false /* usesAdditionalBuffer */),
-            mBuffer->getOriginalBufferSize(), 1, file) < 1) {
-        fclose(file);
-        remove(tmpFileName);
-        return;
-    }
-    // Write data in additional buffer.
-    if (fwrite(mBuffer->getBuffer(true /* usesAdditionalBuffer */),
-            mBuffer->getTailPosition() - mBuffer->getOriginalBufferSize(), 1, file) < 1) {
-        fclose(file);
-        remove(tmpFileName);
-        return;
-    }
-    fclose(file);
-    rename(tmpFileName, fileName);
+    flushAllToFile(fileName, &headerBuffer, &newDictBuffer);
 }
 
 bool DynamicPatriciaTrieWritingHelper::markNodeAsMovedAndSetPosition(
@@ -232,7 +214,8 @@
 }
 
 // Write new PtNode at writingPos.
-bool DynamicPatriciaTrieWritingHelper::writePtNodeWithFullInfoToBuffer(const bool isBlacklisted,
+bool DynamicPatriciaTrieWritingHelper::writePtNodeWithFullInfoToBuffer(
+        BufferWithExtendableBuffer *const bufferToWrite, const bool isBlacklisted,
         const bool isNotAWord, const int parentPos, const int *const codePoints,
         const int codePointCount, const int probability, const int childrenPos,
         const int originalBigramListPos, const int originalShortcutListPos,
@@ -240,38 +223,39 @@
     const int nodePos = *writingPos;
     // Write dummy flags. The Node flags are updated with appropriate flags at the last step of the
     // PtNode writing.
-    if (!DynamicPatriciaTrieWritingUtils::writeFlagsAndAdvancePosition(mBuffer, 0 /* nodeFlags */,
-            writingPos)) {
+    if (!DynamicPatriciaTrieWritingUtils::writeFlagsAndAdvancePosition(bufferToWrite,
+            0 /* nodeFlags */, writingPos)) {
         return false;
     }
     // Calculate a parent offset and write the offset.
     const int parentOffset = (parentPos != NOT_A_DICT_POS) ? parentPos - nodePos : NOT_A_DICT_POS;
-    if (!DynamicPatriciaTrieWritingUtils::writeParentOffsetAndAdvancePosition(mBuffer,
+    if (!DynamicPatriciaTrieWritingUtils::writeParentOffsetAndAdvancePosition(bufferToWrite,
             parentOffset, writingPos)) {
         return false;
     }
     // Write code points
-    if (!DynamicPatriciaTrieWritingUtils::writeCodePointsAndAdvancePosition(mBuffer, codePoints,
-            codePointCount, writingPos)) {
+    if (!DynamicPatriciaTrieWritingUtils::writeCodePointsAndAdvancePosition(bufferToWrite,
+            codePoints, codePointCount, writingPos)) {
         return false;
     }
     // Write probability when the probability is a valid probability, which means this node is
     // terminal.
     if (probability != NOT_A_PROBABILITY) {
-        if (!DynamicPatriciaTrieWritingUtils::writeProbabilityAndAdvancePosition(mBuffer,
+        if (!DynamicPatriciaTrieWritingUtils::writeProbabilityAndAdvancePosition(bufferToWrite,
                 probability, writingPos)) {
             return false;
         }
     }
     // Write children position
-    if (!DynamicPatriciaTrieWritingUtils::writeChildrenPositionAndAdvancePosition(mBuffer,
+    if (!DynamicPatriciaTrieWritingUtils::writeChildrenPositionAndAdvancePosition(bufferToWrite,
             childrenPos, writingPos)) {
         return false;
     }
     // Copy shortcut list when the originalShortcutListPos is valid dictionary position.
     if (originalShortcutListPos != NOT_A_DICT_POS) {
         int fromPos = originalShortcutListPos;
-        if (!mShortcutPolicy->copyAllShortcutsAndReturnIfSucceededOrNot(&fromPos, writingPos)) {
+        if (!mShortcutPolicy->copyAllShortcutsAndReturnIfSucceededOrNot(bufferToWrite, &fromPos,
+                writingPos)) {
             return false;
         }
     }
@@ -279,7 +263,7 @@
     int bigramCount = 0;
     if (originalBigramListPos != NOT_A_DICT_POS) {
         int fromPos = originalBigramListPos;
-        if (!mBigramPolicy->copyAllBigrams(&fromPos, writingPos, &bigramCount)) {
+        if (!mBigramPolicy->copyAllBigrams(bufferToWrite, &fromPos, writingPos, &bigramCount)) {
             return false;
         }
     }
@@ -291,27 +275,29 @@
                     bigramCount > 0 /* hasBigrams */, codePointCount > 1 /* hasMultipleChars */,
                     CHILDREN_POSITION_FIELD_SIZE);
     int flagsFieldPos = nodePos;
-    if (!DynamicPatriciaTrieWritingUtils::writeFlagsAndAdvancePosition(mBuffer, nodeFlags,
+    if (!DynamicPatriciaTrieWritingUtils::writeFlagsAndAdvancePosition(bufferToWrite, nodeFlags,
             &flagsFieldPos)) {
         return false;
     }
     return true;
 }
 
-bool DynamicPatriciaTrieWritingHelper::writePtNodeToBuffer(const int parentPos,
+bool DynamicPatriciaTrieWritingHelper::writePtNodeToBuffer(
+        BufferWithExtendableBuffer *const bufferToWrite, const int parentPos,
         const int *const codePoints, const int codePointCount, const int probability,
         int *const writingPos) {
-    return writePtNodeWithFullInfoToBuffer(false /* isBlacklisted */, false /* isNotAWord */,
-            parentPos, codePoints, codePointCount, probability,
+    return writePtNodeWithFullInfoToBuffer(bufferToWrite, false /* isBlacklisted */,
+            false /* isNotAWord */, parentPos, codePoints, codePointCount, probability,
             NOT_A_DICT_POS /* childrenPos */, NOT_A_DICT_POS /* originalBigramsPos */,
             NOT_A_DICT_POS /* originalShortcutPos */, writingPos);
 }
 
 bool DynamicPatriciaTrieWritingHelper::writePtNodeToBufferByCopyingPtNodeInfo(
+        BufferWithExtendableBuffer *const bufferToWrite,
         const DynamicPatriciaTrieNodeReader *const originalNode, const int parentPos,
         const int *const codePoints, const int codePointCount, const int probability,
         int *const writingPos) {
-    return writePtNodeWithFullInfoToBuffer(originalNode->isBlacklisted(),
+    return writePtNodeWithFullInfoToBuffer(bufferToWrite, originalNode->isBlacklisted(),
             originalNode->isNotAWord(), parentPos, codePoints, codePointCount, probability,
             originalNode->getChildrenPos(), originalNode->getBigramsPos(),
             originalNode->getShortcutPos(), writingPos);
@@ -345,8 +331,9 @@
         if (!markNodeAsMovedAndSetPosition(originalPtNode, movedPos, movedPos)) {
             return false;
         }
-        if (!writePtNodeToBufferByCopyingPtNodeInfo(originalPtNode, originalPtNode->getParentPos(),
-                codePoints, originalPtNode->getCodePointCount(), probability, &movedPos)) {
+        if (!writePtNodeToBufferByCopyingPtNodeInfo(mBuffer, originalPtNode,
+                originalPtNode->getParentPos(), codePoints, originalPtNode->getCodePointCount(),
+                probability, &movedPos)) {
             return false;
         }
     }
@@ -374,8 +361,8 @@
             1 /* arraySize */, &writingPos)) {
         return false;
     }
-    if (!writePtNodeToBuffer(parentPtNodePos, nodeCodePoints, nodeCodePointCount, probability,
-            &writingPos)) {
+    if (!writePtNodeToBuffer(mBuffer, parentPtNodePos, nodeCodePoints, nodeCodePointCount,
+            probability, &writingPos)) {
         return false;
     }
     if (!DynamicPatriciaTrieWritingUtils::writeForwardLinkPositionAndAdvancePosition(mBuffer,
@@ -404,8 +391,9 @@
     // Write the 1st part of the reallocating node. The children position will be updated later
     // with actual children position.
     const int newProbability = addsExtraChild ? NOT_A_PROBABILITY : probabilityOfNewPtNode;
-    if (!writePtNodeToBuffer(reallocatingPtNode->getParentPos(), reallocatingPtNodeCodePoints,
-            overlappingCodePointCount, newProbability, &writingPos)) {
+    if (!writePtNodeToBuffer(mBuffer, reallocatingPtNode->getParentPos(),
+            reallocatingPtNodeCodePoints, overlappingCodePointCount, newProbability,
+            &writingPos)) {
         return false;
     }
     const int actualChildrenPos = writingPos;
@@ -417,14 +405,15 @@
     }
     // Write the 2nd part of the reallocating node.
     const int secondPartOfReallocatedPtNodePos = writingPos;
-    if (!writePtNodeToBufferByCopyingPtNodeInfo(reallocatingPtNode, firstPartOfReallocatedPtNodePos,
+    if (!writePtNodeToBufferByCopyingPtNodeInfo(mBuffer, reallocatingPtNode,
+            firstPartOfReallocatedPtNodePos,
             reallocatingPtNodeCodePoints + overlappingCodePointCount,
             reallocatingPtNode->getCodePointCount() - overlappingCodePointCount,
             reallocatingPtNode->getProbability(), &writingPos)) {
         return false;
     }
     if (addsExtraChild) {
-        if (!writePtNodeToBuffer(firstPartOfReallocatedPtNodePos,
+        if (!writePtNodeToBuffer(mBuffer, firstPartOfReallocatedPtNodePos,
                 newNodeCodePoints + overlappingCodePointCount,
                 newNodeCodePointCount - overlappingCodePointCount, probabilityOfNewPtNode,
                 &writingPos)) {
@@ -452,4 +441,64 @@
     return true;
 }
 
+// TODO: Create a struct which contains header, body and etc... and use here as an argument.
+void DynamicPatriciaTrieWritingHelper::flushAllToFile(const char *const fileName,
+        BufferWithExtendableBuffer *const dictHeader,
+        BufferWithExtendableBuffer *const dictBody) const {
+    const int tmpFileNameBufSize = strlen(fileName)
+            + strlen(TEMP_FILE_SUFFIX_FOR_WRITING_DICT_FILE) + 1 /* terminator */;
+    // Name of a temporary file used for writing that is a connected string of original name and
+    // TEMP_FILE_SUFFIX_FOR_WRITING_DICT_FILE.
+    char tmpFileName[tmpFileNameBufSize];
+    snprintf(tmpFileName, tmpFileNameBufSize, "%s%s", fileName,
+            TEMP_FILE_SUFFIX_FOR_WRITING_DICT_FILE);
+    FILE *const file = fopen(tmpFileName, "wb");
+    if (!file) {
+        AKLOGI("Dictionary file %s cannnot be opened.", tmpFileName);
+        ASSERT(false);
+        return;
+    }
+    // Write the dictionary header.
+    if (!writeBufferToFilePointer(file, dictHeader)) {
+        remove(tmpFileName);
+        AKLOGI("Dictionary header cannnot be written. size: %d", dictHeader->getTailPosition());
+        ASSERT(false);
+        return;
+    }
+    // Write the dictionary body.
+    if (!writeBufferToFilePointer(file, dictBody)) {
+        remove(tmpFileName);
+        AKLOGI("Dictionary body cannnot be written. size: %d", dictBody->getTailPosition());
+        ASSERT(false);
+        return;
+    }
+    fclose(file);
+    rename(tmpFileName, fileName);
+}
+
+// This closes file pointer when an error is caused and returns whether the writing was succeeded
+// or not.
+bool DynamicPatriciaTrieWritingHelper::writeBufferToFilePointer(FILE *const file,
+        const BufferWithExtendableBuffer *const buffer) const {
+    const int originalBufSize = buffer->getOriginalBufferSize();
+    if (originalBufSize > 0 && fwrite(buffer->getBuffer(false /* usesAdditionalBuffer */),
+            originalBufSize, 1, file) < 1) {
+        fclose(file);
+        return false;
+    }
+    const int additionalBufSize = buffer->getTailPosition() - buffer->getOriginalBufferSize();
+    if (additionalBufSize > 0 && fwrite(buffer->getBuffer(true /* usesAdditionalBuffer */),
+            additionalBufSize, 1, file) < 1) {
+        fclose(file);
+        return false;
+    }
+    return true;
+}
+
+bool DynamicPatriciaTrieWritingHelper::runGC(const int rootPtNodeArrayPos,
+        BufferWithExtendableBuffer *const bufferToWrite) {
+    // TODO: Implement.
+    return false;
+}
+
 } // namespace latinime
diff --git a/native/jni/src/suggest/policyimpl/dictionary/dynamic_patricia_trie_writing_helper.h b/native/jni/src/suggest/policyimpl/dictionary/dynamic_patricia_trie_writing_helper.h
index 219ea98..8f78d84 100644
--- a/native/jni/src/suggest/policyimpl/dictionary/dynamic_patricia_trie_writing_helper.h
+++ b/native/jni/src/suggest/policyimpl/dictionary/dynamic_patricia_trie_writing_helper.h
@@ -17,6 +17,7 @@
 #ifndef LATINIME_DYNAMIC_PATRICIA_TRIE_WRITING_HELPER_H
 #define LATINIME_DYNAMIC_PATRICIA_TRIE_WRITING_HELPER_H
 
+#include <cstdio>
 #include <stdint.h>
 
 #include "defines.h"
@@ -51,7 +52,8 @@
 
     void writeToDictFile(const char *const fileName, const HeaderPolicy *const headerPolicy);
 
-    void writeToDictFileWithGC(const char *const fileName, const HeaderPolicy *const headerPolicy);
+    void writeToDictFileWithGC(const int rootPtNodeArrayPos, const char *const fileName,
+            const HeaderPolicy *const headerPolicy);
 
  private:
     DISALLOW_IMPLICIT_CONSTRUCTORS(DynamicPatriciaTrieWritingHelper);
@@ -66,15 +68,17 @@
     bool markNodeAsMovedAndSetPosition(const DynamicPatriciaTrieNodeReader *const nodeToUpdate,
             const int movedPos, const int bigramLinkedNodePos);
 
-    bool writePtNodeWithFullInfoToBuffer(const bool isBlacklisted, const bool isNotAWord,
+    bool writePtNodeWithFullInfoToBuffer(BufferWithExtendableBuffer *const bufferToWrite,
+            const bool isBlacklisted, const bool isNotAWord,
             const int parentPos,  const int *const codePoints, const int codePointCount,
             const int probability, const int childrenPos, const int originalBigramListPos,
             const int originalShortcutListPos, int *const writingPos);
 
-    bool writePtNodeToBuffer(const int parentPos, const int *const codePoints,
-            const int codePointCount, const int probability, int *const writingPos);
+    bool writePtNodeToBuffer(BufferWithExtendableBuffer *const bufferToWrite,
+            const int parentPos, const int *const codePoints, const int codePointCount,
+            const int probability, int *const writingPos);
 
-    bool writePtNodeToBufferByCopyingPtNodeInfo(
+    bool writePtNodeToBufferByCopyingPtNodeInfo(BufferWithExtendableBuffer *const bufferToWrite,
             const DynamicPatriciaTrieNodeReader *const originalNode, const int parentPos,
             const int *const codePoints, const int codePointCount, const int probability,
             int *const writingPos);
@@ -97,6 +101,15 @@
             const int *const reallocatingPtNodeCodePoints, const int overlappingCodePointCount,
             const int probabilityOfNewPtNode, const int *const newNodeCodePoints,
             const int newNodeCodePointCount);
+
+    void flushAllToFile(const char *const fileName,
+            BufferWithExtendableBuffer *const dictHeader,
+            BufferWithExtendableBuffer *const dictBody) const;
+
+    bool writeBufferToFilePointer(FILE *const file,
+            const BufferWithExtendableBuffer *const buffer) const;
+
+    bool runGC(const int rootPtNodeArrayPos, BufferWithExtendableBuffer *const bufferToWrite);
 };
 } // namespace latinime
 #endif /* LATINIME_DYNAMIC_PATRICIA_TRIE_WRITING_HELPER_H */
diff --git a/native/jni/src/suggest/policyimpl/dictionary/shortcut/dynamic_shortcut_list_policy.h b/native/jni/src/suggest/policyimpl/dictionary/shortcut/dynamic_shortcut_list_policy.h
index 1803c09..bd3211f 100644
--- a/native/jni/src/suggest/policyimpl/dictionary/shortcut/dynamic_shortcut_list_policy.h
+++ b/native/jni/src/suggest/policyimpl/dictionary/shortcut/dynamic_shortcut_list_policy.h
@@ -31,7 +31,7 @@
  */
 class DynamicShortcutListPolicy : public DictionaryShortcutsStructurePolicy {
  public:
-    explicit DynamicShortcutListPolicy(BufferWithExtendableBuffer *const buffer)
+    explicit DynamicShortcutListPolicy(const BufferWithExtendableBuffer *const buffer)
             : mBuffer(buffer) {}
 
     ~DynamicShortcutListPolicy() {}
@@ -82,18 +82,20 @@
         }
     }
 
-    // Copy shortcuts from the shortcut list that starts at fromPos to toPos and advance these
-    // positions after the shortcut lists. This returns whether the copy was succeeded or not.
-    bool copyAllShortcutsAndReturnIfSucceededOrNot(int *const fromPos, int *const toPos) {
+    // Copy shortcuts from the shortcut list that starts at fromPos in mBuffer to toPos in
+    // bufferToWrite and advance these positions after the shortcut lists. This returns whether
+    // the copy was succeeded or not.
+    bool copyAllShortcutsAndReturnIfSucceededOrNot(BufferWithExtendableBuffer *const bufferToWrite,
+            int *const fromPos, int *const toPos) const {
         const bool usesAdditionalBuffer = mBuffer->isInAdditionalBuffer(*fromPos);
-        const uint8_t *const buffer = mBuffer->getBuffer(usesAdditionalBuffer);
         if (usesAdditionalBuffer) {
             *fromPos -= mBuffer->getOriginalBufferSize();
         }
         const int shortcutListSize = ShortcutListReadingUtils
-                ::getShortcutListSizeAndForwardPointer(buffer, fromPos);
+                ::getShortcutListSizeAndForwardPointer(mBuffer->getBuffer(usesAdditionalBuffer),
+                        fromPos);
         // Copy shortcut list size.
-        if (!mBuffer->writeUintAndAdvancePosition(
+        if (!bufferToWrite->writeUintAndAdvancePosition(
                 shortcutListSize + ShortcutListReadingUtils::getShortcutListSizeFieldSize(),
                 ShortcutListReadingUtils::getShortcutListSizeFieldSize(), toPos)) {
             return false;
@@ -102,7 +104,7 @@
         for (int i = 0; i < shortcutListSize; ++i) {
             const uint8_t data = ByteArrayUtils::readUint8AndAdvancePosition(
                     mBuffer->getBuffer(usesAdditionalBuffer), fromPos);
-            if (!mBuffer->writeUintAndAdvancePosition(data, 1 /* size */, toPos)) {
+            if (!bufferToWrite->writeUintAndAdvancePosition(data, 1 /* size */, toPos)) {
                 return false;
             }
         }
@@ -115,7 +117,7 @@
  private:
     DISALLOW_IMPLICIT_CONSTRUCTORS(DynamicShortcutListPolicy);
 
-    BufferWithExtendableBuffer *const mBuffer;
+    const BufferWithExtendableBuffer *const mBuffer;
 };
 } // namespace latinime
 #endif // LATINIME_DYNAMIC_SHORTCUT_LIST_POLICY_H