am 6a71f061: Fix UserHistoryBigram data contention in UserHistoryDictionary
* commit '6a71f0610c137c613a5fa44a658f31e9f4ec5525': Fix UserHistoryBigram data contention in UserHistoryDictionarymain
commit
ee78e780fc
|
@ -32,6 +32,7 @@ import com.android.inputmethod.latin.UserHistoryForgettingCurveUtils.ForgettingC
|
|||
import java.lang.ref.SoftReference;
|
||||
import java.util.HashMap;
|
||||
import java.util.concurrent.ConcurrentHashMap;
|
||||
import java.util.concurrent.locks.ReentrantLock;
|
||||
|
||||
/**
|
||||
* Locally gathers stats about the words user types and various other signals like auto-correction
|
||||
|
@ -40,6 +41,8 @@ import java.util.concurrent.ConcurrentHashMap;
|
|||
public class UserHistoryDictionary extends ExpandableDictionary {
|
||||
private static final String TAG = "UserHistoryDictionary";
|
||||
public static final boolean DBG_SAVE_RESTORE = false;
|
||||
public static final boolean DBG_STRESS_TEST = false;
|
||||
public static final boolean DBG_ALWAYS_WRITE = false;
|
||||
public static final boolean PROFILE_SAVE_RESTORE = LatinImeLogger.sDBG;
|
||||
|
||||
/** Any pair being typed or picked */
|
||||
|
@ -82,7 +85,7 @@ public class UserHistoryDictionary extends ExpandableDictionary {
|
|||
|
||||
private final UserHistoryDictionaryBigramList mBigramList =
|
||||
new UserHistoryDictionaryBigramList();
|
||||
private static volatile boolean sUpdatingDB = false;
|
||||
private final ReentrantLock mBigramListLock = new ReentrantLock();
|
||||
private final SharedPreferences mPrefs;
|
||||
|
||||
private final static HashMap<String, String> sDictProjectionMap;
|
||||
|
@ -173,28 +176,38 @@ public class UserHistoryDictionary extends ExpandableDictionary {
|
|||
* The second word may not be null (a NullPointerException would be thrown).
|
||||
*/
|
||||
public int addToUserHistory(final String word1, String word2, boolean isValid) {
|
||||
super.addWord(word2, null /* the "shortcut" parameter is null */, FREQUENCY_FOR_TYPED);
|
||||
// Do not insert a word as a bigram of itself
|
||||
if (word2.equals(word1)) {
|
||||
return 0;
|
||||
if (mBigramListLock.tryLock()) {
|
||||
try {
|
||||
super.addWord(
|
||||
word2, null /* the "shortcut" parameter is null */, FREQUENCY_FOR_TYPED);
|
||||
// Do not insert a word as a bigram of itself
|
||||
if (word2.equals(word1)) {
|
||||
return 0;
|
||||
}
|
||||
final int freq;
|
||||
if (null == word1) {
|
||||
freq = FREQUENCY_FOR_TYPED;
|
||||
} else {
|
||||
freq = super.setBigramAndGetFrequency(
|
||||
word1, word2, new ForgettingCurveParams(isValid));
|
||||
}
|
||||
mBigramList.addBigram(word1, word2);
|
||||
return freq;
|
||||
} finally {
|
||||
mBigramListLock.unlock();
|
||||
}
|
||||
}
|
||||
final int freq;
|
||||
if (null == word1) {
|
||||
freq = FREQUENCY_FOR_TYPED;
|
||||
} else {
|
||||
freq = super.setBigramAndGetFrequency(word1, word2, new ForgettingCurveParams(isValid));
|
||||
}
|
||||
synchronized (mBigramList) {
|
||||
mBigramList.addBigram(word1, word2);
|
||||
}
|
||||
|
||||
return freq;
|
||||
return -1;
|
||||
}
|
||||
|
||||
public boolean cancelAddingUserHistory(String word1, String word2) {
|
||||
synchronized (mBigramList) {
|
||||
if (mBigramList.removeBigram(word1, word2)) {
|
||||
return super.removeBigram(word1, word2);
|
||||
if (mBigramListLock.tryLock()) {
|
||||
try {
|
||||
if (mBigramList.removeBigram(word1, word2)) {
|
||||
return super.removeBigram(word1, word2);
|
||||
}
|
||||
} finally {
|
||||
mBigramListLock.unlock();
|
||||
}
|
||||
}
|
||||
return false;
|
||||
|
@ -204,70 +217,73 @@ public class UserHistoryDictionary extends ExpandableDictionary {
|
|||
* Schedules a background thread to write any pending words to the database.
|
||||
*/
|
||||
private void flushPendingWrites() {
|
||||
synchronized (mBigramList) {
|
||||
// Nothing pending? Return
|
||||
if (mBigramList.isEmpty()) return;
|
||||
// Create a background thread to write the pending entries
|
||||
new UpdateDbTask(sOpenHelper, mBigramList, mLocale, this, mPrefs).execute();
|
||||
}
|
||||
}
|
||||
|
||||
/** Used for testing purpose **/
|
||||
void waitUntilUpdateDBDone() {
|
||||
synchronized (mBigramList) {
|
||||
while (sUpdatingDB) {
|
||||
try {
|
||||
Thread.sleep(100);
|
||||
} catch (InterruptedException e) {
|
||||
}
|
||||
}
|
||||
if (mBigramListLock.isLocked()) {
|
||||
return;
|
||||
}
|
||||
// Create a background thread to write the pending entries
|
||||
new UpdateDbTask(sOpenHelper, mBigramList, mLocale, this, mPrefs).execute();
|
||||
}
|
||||
|
||||
@Override
|
||||
public void loadDictionaryAsync() {
|
||||
synchronized(mBigramList) {
|
||||
final long last = SettingsValues.getLastUserHistoryWriteTime(mPrefs, mLocale);
|
||||
final boolean initializing = last == 0;
|
||||
final long now = System.currentTimeMillis();
|
||||
// Load the words that correspond to the current input locale
|
||||
final Cursor cursor = query(MAIN_COLUMN_LOCALE + "=?", new String[] { mLocale });
|
||||
if (null == cursor) return;
|
||||
// This must be run on non-main thread
|
||||
mBigramListLock.lock();
|
||||
try {
|
||||
loadDictionaryAsyncLocked();
|
||||
} finally {
|
||||
mBigramListLock.unlock();
|
||||
}
|
||||
}
|
||||
|
||||
private void loadDictionaryAsyncLocked() {
|
||||
if (DBG_STRESS_TEST) {
|
||||
try {
|
||||
if (cursor.moveToFirst()) {
|
||||
final int word1Index = cursor.getColumnIndex(MAIN_COLUMN_WORD1);
|
||||
final int word2Index = cursor.getColumnIndex(MAIN_COLUMN_WORD2);
|
||||
final int fcIndex = cursor.getColumnIndex(COLUMN_FORGETTING_CURVE_VALUE);
|
||||
while (!cursor.isAfterLast()) {
|
||||
final String word1 = cursor.getString(word1Index);
|
||||
final String word2 = cursor.getString(word2Index);
|
||||
final int fc = cursor.getInt(fcIndex);
|
||||
if (DBG_SAVE_RESTORE) {
|
||||
Log.d(TAG, "--- Load user history: " + word1 + ", " + word2 + ","
|
||||
+ mLocale + "," + this);
|
||||
}
|
||||
// Safeguard against adding really long words. Stack may overflow due
|
||||
// to recursive lookup
|
||||
if (null == word1) {
|
||||
super.addWord(word2, null /* shortcut */, fc);
|
||||
} else if (word1.length() < BinaryDictionary.MAX_WORD_LENGTH
|
||||
&& word2.length() < BinaryDictionary.MAX_WORD_LENGTH) {
|
||||
super.setBigramAndGetFrequency(
|
||||
word1, word2, initializing ? new ForgettingCurveParams(true)
|
||||
: new ForgettingCurveParams(fc, now, last));
|
||||
}
|
||||
mBigramList.addBigram(word1, word2, (byte)fc);
|
||||
cursor.moveToNext();
|
||||
Log.w(TAG, "Start stress in loading: " + mLocale);
|
||||
Thread.sleep(15000);
|
||||
Log.w(TAG, "End stress in loading");
|
||||
} catch (InterruptedException e) {
|
||||
}
|
||||
}
|
||||
final long last = SettingsValues.getLastUserHistoryWriteTime(mPrefs, mLocale);
|
||||
final boolean initializing = last == 0;
|
||||
final long now = System.currentTimeMillis();
|
||||
// Load the words that correspond to the current input locale
|
||||
final Cursor cursor = query(MAIN_COLUMN_LOCALE + "=?", new String[] { mLocale });
|
||||
if (null == cursor) return;
|
||||
try {
|
||||
// TODO: Call SQLiteDataBase.beginTransaction / SQLiteDataBase.endTransaction
|
||||
if (cursor.moveToFirst()) {
|
||||
final int word1Index = cursor.getColumnIndex(MAIN_COLUMN_WORD1);
|
||||
final int word2Index = cursor.getColumnIndex(MAIN_COLUMN_WORD2);
|
||||
final int fcIndex = cursor.getColumnIndex(COLUMN_FORGETTING_CURVE_VALUE);
|
||||
while (!cursor.isAfterLast()) {
|
||||
final String word1 = cursor.getString(word1Index);
|
||||
final String word2 = cursor.getString(word2Index);
|
||||
final int fc = cursor.getInt(fcIndex);
|
||||
if (DBG_SAVE_RESTORE) {
|
||||
Log.d(TAG, "--- Load user history: " + word1 + ", " + word2 + ","
|
||||
+ mLocale + "," + this);
|
||||
}
|
||||
// Safeguard against adding really long words. Stack may overflow due
|
||||
// to recursive lookup
|
||||
if (null == word1) {
|
||||
super.addWord(word2, null /* shortcut */, fc);
|
||||
} else if (word1.length() < BinaryDictionary.MAX_WORD_LENGTH
|
||||
&& word2.length() < BinaryDictionary.MAX_WORD_LENGTH) {
|
||||
super.setBigramAndGetFrequency(
|
||||
word1, word2, initializing ? new ForgettingCurveParams(true)
|
||||
: new ForgettingCurveParams(fc, now, last));
|
||||
}
|
||||
mBigramList.addBigram(word1, word2, (byte)fc);
|
||||
cursor.moveToNext();
|
||||
}
|
||||
} finally {
|
||||
cursor.close();
|
||||
if (PROFILE_SAVE_RESTORE) {
|
||||
final long diff = System.currentTimeMillis() - now;
|
||||
Log.w(TAG, "PROF: Load User HistoryDictionary: "
|
||||
+ mLocale + ", " + diff + "ms.");
|
||||
}
|
||||
}
|
||||
} finally {
|
||||
cursor.close();
|
||||
if (PROFILE_SAVE_RESTORE) {
|
||||
final long diff = System.currentTimeMillis() - now;
|
||||
Log.w(TAG, "PROF: Load User HistoryDictionary: "
|
||||
+ mLocale + ", " + diff + "ms.");
|
||||
}
|
||||
}
|
||||
}
|
||||
|
@ -388,146 +404,167 @@ public class UserHistoryDictionary extends ExpandableDictionary {
|
|||
}
|
||||
|
||||
@Override
|
||||
protected void onPreExecute() {
|
||||
sUpdatingDB = true;
|
||||
protected Void doInBackground(Void... v) {
|
||||
SQLiteDatabase db = null;
|
||||
if (mUserHistoryDictionary.mBigramListLock.tryLock()) {
|
||||
try {
|
||||
try {
|
||||
db = mDbHelper.getWritableDatabase();
|
||||
} catch (android.database.sqlite.SQLiteCantOpenDatabaseException e) {
|
||||
// If we can't open the db, don't do anything. Exit through the next test
|
||||
// for non-nullity of the db variable.
|
||||
}
|
||||
if (null == db) {
|
||||
// Not much we can do. Just exit.
|
||||
return null;
|
||||
}
|
||||
db.beginTransaction();
|
||||
return doLoadTaskLocked(db);
|
||||
} finally {
|
||||
if (db != null) {
|
||||
db.endTransaction();
|
||||
}
|
||||
mUserHistoryDictionary.mBigramListLock.unlock();
|
||||
}
|
||||
}
|
||||
return null;
|
||||
}
|
||||
|
||||
@Override
|
||||
protected Void doInBackground(Void... v) {
|
||||
synchronized(mBigramList) {
|
||||
final long now = PROFILE_SAVE_RESTORE ? System.currentTimeMillis() : 0;
|
||||
int profTotal = 0;
|
||||
int profInsert = 0;
|
||||
int profDelete = 0;
|
||||
SQLiteDatabase db = null;
|
||||
private Void doLoadTaskLocked(SQLiteDatabase db) {
|
||||
if (DBG_STRESS_TEST) {
|
||||
try {
|
||||
db = mDbHelper.getWritableDatabase();
|
||||
} catch (android.database.sqlite.SQLiteCantOpenDatabaseException e) {
|
||||
// If we can't open the db, don't do anything. Exit through the next test
|
||||
// for non-nullity of the db variable.
|
||||
Log.w(TAG, "Start stress in closing: " + mLocale);
|
||||
Thread.sleep(15000);
|
||||
Log.w(TAG, "End stress in closing");
|
||||
} catch (InterruptedException e) {
|
||||
}
|
||||
if (null == db) {
|
||||
// Not much we can do. Just exit.
|
||||
sUpdatingDB = false;
|
||||
return null;
|
||||
}
|
||||
db.execSQL("PRAGMA foreign_keys = ON;");
|
||||
final boolean addLevel0Bigram = mBigramList.size() <= sMaxHistoryBigrams;
|
||||
}
|
||||
final long now = PROFILE_SAVE_RESTORE ? System.currentTimeMillis() : 0;
|
||||
int profTotal = 0;
|
||||
int profInsert = 0;
|
||||
int profDelete = 0;
|
||||
db.execSQL("PRAGMA foreign_keys = ON;");
|
||||
final boolean addLevel0Bigram = mBigramList.size() <= sMaxHistoryBigrams;
|
||||
|
||||
// Write all the entries to the db
|
||||
for (String word1 : mBigramList.keySet()) {
|
||||
final HashMap<String, Byte> word1Bigrams = mBigramList.getBigrams(word1);
|
||||
for (String word2 : word1Bigrams.keySet()) {
|
||||
if (PROFILE_SAVE_RESTORE) {
|
||||
++profTotal;
|
||||
// Write all the entries to the db
|
||||
for (String word1 : mBigramList.keySet()) {
|
||||
final HashMap<String, Byte> word1Bigrams = mBigramList.getBigrams(word1);
|
||||
for (String word2 : word1Bigrams.keySet()) {
|
||||
if (PROFILE_SAVE_RESTORE) {
|
||||
++profTotal;
|
||||
}
|
||||
// Get new frequency. Do not insert unigrams/bigrams which freq is "-1".
|
||||
final int freq; // -1, or 0~255
|
||||
if (word1 == null) { // unigram
|
||||
freq = FREQUENCY_FOR_TYPED;
|
||||
final byte prevFc = word1Bigrams.get(word2);
|
||||
if (prevFc == FREQUENCY_FOR_TYPED) {
|
||||
// No need to update since we found no changes for this entry.
|
||||
// Just skip to the next entry.
|
||||
if (DBG_SAVE_RESTORE) {
|
||||
Log.d(TAG, "Skip update user history: " + word1 + "," + word2
|
||||
+ "," + prevFc);
|
||||
}
|
||||
if (!DBG_ALWAYS_WRITE) {
|
||||
continue;
|
||||
}
|
||||
}
|
||||
// Get new frequency. Do not insert unigrams/bigrams which freq is "-1".
|
||||
final int freq; // -1, or 0~255
|
||||
if (word1 == null) { // unigram
|
||||
freq = FREQUENCY_FOR_TYPED;
|
||||
} else { // bigram
|
||||
final NextWord nw = mUserHistoryDictionary.getBigramWord(word1, word2);
|
||||
if (nw != null) {
|
||||
final ForgettingCurveParams fcp = nw.getFcParams();
|
||||
final byte prevFc = word1Bigrams.get(word2);
|
||||
if (prevFc == FREQUENCY_FOR_TYPED) {
|
||||
final byte fc = (byte)fcp.getFc();
|
||||
final boolean isValid = fcp.isValid();
|
||||
if (prevFc > 0 && prevFc == fc) {
|
||||
// No need to update since we found no changes for this entry.
|
||||
// Just skip to the next entry.
|
||||
if (DBG_SAVE_RESTORE) {
|
||||
Log.d(TAG, "Skip update user history: " + word1 + "," + word2
|
||||
+ "," + prevFc);
|
||||
Log.d(TAG, "Skip update user history: " + word1 + ","
|
||||
+ word2 + "," + prevFc);
|
||||
}
|
||||
continue;
|
||||
}
|
||||
} else { // bigram
|
||||
final NextWord nw = mUserHistoryDictionary.getBigramWord(word1, word2);
|
||||
if (nw != null) {
|
||||
final ForgettingCurveParams fcp = nw.getFcParams();
|
||||
final byte prevFc = word1Bigrams.get(word2);
|
||||
final byte fc = (byte)fcp.getFc();
|
||||
final boolean isValid = fcp.isValid();
|
||||
if (prevFc > 0 && prevFc == fc) {
|
||||
// No need to update since we found no changes for this entry.
|
||||
// Just skip to the next entry.
|
||||
if (DBG_SAVE_RESTORE) {
|
||||
Log.d(TAG, "Skip update user history: " + word1 + ","
|
||||
+ word2 + "," + prevFc);
|
||||
}
|
||||
if (!DBG_ALWAYS_WRITE) {
|
||||
continue;
|
||||
} else if (UserHistoryForgettingCurveUtils.
|
||||
needsToSave(fc, isValid, addLevel0Bigram)) {
|
||||
freq = fc;
|
||||
} else {
|
||||
freq = -1;
|
||||
freq = fc;
|
||||
}
|
||||
} else if (UserHistoryForgettingCurveUtils.
|
||||
needsToSave(fc, isValid, addLevel0Bigram)) {
|
||||
freq = fc;
|
||||
} else {
|
||||
freq = -1;
|
||||
}
|
||||
} else {
|
||||
freq = -1;
|
||||
}
|
||||
}
|
||||
// TODO: this process of making a text search for each pair each time
|
||||
// is terribly inefficient. Optimize this.
|
||||
// Find pair id
|
||||
Cursor c = null;
|
||||
try {
|
||||
if (null != word1) {
|
||||
c = db.query(MAIN_TABLE_NAME, new String[] { MAIN_COLUMN_ID },
|
||||
MAIN_COLUMN_WORD1 + "=? AND " + MAIN_COLUMN_WORD2 + "=? AND "
|
||||
+ MAIN_COLUMN_LOCALE + "=?",
|
||||
new String[] { word1, word2, mLocale }, null, null,
|
||||
null);
|
||||
} else {
|
||||
c = db.query(MAIN_TABLE_NAME, new String[] { MAIN_COLUMN_ID },
|
||||
MAIN_COLUMN_WORD1 + " IS NULL AND " + MAIN_COLUMN_WORD2
|
||||
+ "=? AND " + MAIN_COLUMN_LOCALE + "=?",
|
||||
new String[] { word2, mLocale }, null, null, null);
|
||||
}
|
||||
// TODO: this process of making a text search for each pair each time
|
||||
// is terribly inefficient. Optimize this.
|
||||
// Find pair id
|
||||
Cursor c = null;
|
||||
try {
|
||||
if (null != word1) {
|
||||
c = db.query(MAIN_TABLE_NAME, new String[] { MAIN_COLUMN_ID },
|
||||
MAIN_COLUMN_WORD1 + "=? AND " + MAIN_COLUMN_WORD2 + "=? AND "
|
||||
+ MAIN_COLUMN_LOCALE + "=?",
|
||||
new String[] { word1, word2, mLocale }, null, null,
|
||||
null);
|
||||
} else {
|
||||
c = db.query(MAIN_TABLE_NAME, new String[] { MAIN_COLUMN_ID },
|
||||
MAIN_COLUMN_WORD1 + " IS NULL AND " + MAIN_COLUMN_WORD2
|
||||
+ "=? AND " + MAIN_COLUMN_LOCALE + "=?",
|
||||
new String[] { word2, mLocale }, null, null, null);
|
||||
}
|
||||
|
||||
final int pairId;
|
||||
if (c.moveToFirst()) {
|
||||
if (PROFILE_SAVE_RESTORE) {
|
||||
++profDelete;
|
||||
}
|
||||
// Delete existing pair
|
||||
pairId = c.getInt(c.getColumnIndex(MAIN_COLUMN_ID));
|
||||
db.delete(FREQ_TABLE_NAME, FREQ_COLUMN_PAIR_ID + "=?",
|
||||
new String[] { Integer.toString(pairId) });
|
||||
} else {
|
||||
// Create new pair
|
||||
Long pairIdLong = db.insert(MAIN_TABLE_NAME, null,
|
||||
getContentValues(word1, word2, mLocale));
|
||||
pairId = pairIdLong.intValue();
|
||||
final int pairId;
|
||||
if (c.moveToFirst()) {
|
||||
if (PROFILE_SAVE_RESTORE) {
|
||||
++profDelete;
|
||||
}
|
||||
if (freq > 0) {
|
||||
if (PROFILE_SAVE_RESTORE) {
|
||||
++profInsert;
|
||||
}
|
||||
if (DBG_SAVE_RESTORE) {
|
||||
Log.d(TAG, "--- Save user history: " + word1 + ", " + word2
|
||||
+ mLocale + "," + this);
|
||||
}
|
||||
// Insert new frequency
|
||||
db.insert(FREQ_TABLE_NAME, null,
|
||||
getFrequencyContentValues(pairId, freq));
|
||||
// Update an existing bigram entry in mBigramList too in order to
|
||||
// synchronize the SQL DB and mBigramList.
|
||||
mBigramList.updateBigram(word1, word2, (byte)freq);
|
||||
// Delete existing pair
|
||||
pairId = c.getInt(c.getColumnIndex(MAIN_COLUMN_ID));
|
||||
db.delete(FREQ_TABLE_NAME, FREQ_COLUMN_PAIR_ID + "=?",
|
||||
new String[] { Integer.toString(pairId) });
|
||||
} else {
|
||||
// Create new pair
|
||||
Long pairIdLong = db.insert(MAIN_TABLE_NAME, null,
|
||||
getContentValues(word1, word2, mLocale));
|
||||
pairId = pairIdLong.intValue();
|
||||
}
|
||||
if (freq > 0) {
|
||||
if (PROFILE_SAVE_RESTORE) {
|
||||
++profInsert;
|
||||
}
|
||||
} finally {
|
||||
if (c != null) {
|
||||
c.close();
|
||||
if (DBG_SAVE_RESTORE) {
|
||||
Log.d(TAG, "--- Save user history: " + word1 + ", " + word2
|
||||
+ mLocale + "," + this);
|
||||
}
|
||||
// Insert new frequency
|
||||
db.insert(FREQ_TABLE_NAME, null,
|
||||
getFrequencyContentValues(pairId, freq));
|
||||
// Update an existing bigram entry in mBigramList too in order to
|
||||
// synchronize the SQL DB and mBigramList.
|
||||
mBigramList.updateBigram(word1, word2, (byte)freq);
|
||||
}
|
||||
} finally {
|
||||
if (c != null) {
|
||||
c.close();
|
||||
}
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
checkPruneData(db);
|
||||
// Save the timestamp after we finish writing the SQL DB.
|
||||
SettingsValues.setLastUserHistoryWriteTime(mPrefs, mLocale);
|
||||
sUpdatingDB = false;
|
||||
if (PROFILE_SAVE_RESTORE) {
|
||||
final long diff = System.currentTimeMillis() - now;
|
||||
Log.w(TAG, "PROF: Write User HistoryDictionary: " + mLocale + ", "+ diff
|
||||
+ "ms. Total: " + profTotal + ". Insert: " + profInsert + ". Delete: "
|
||||
+ profDelete);
|
||||
}
|
||||
return null;
|
||||
} // synchronized
|
||||
checkPruneData(db);
|
||||
// Save the timestamp after we finish writing the SQL DB.
|
||||
SettingsValues.setLastUserHistoryWriteTime(mPrefs, mLocale);
|
||||
if (PROFILE_SAVE_RESTORE) {
|
||||
final long diff = System.currentTimeMillis() - now;
|
||||
Log.w(TAG, "PROF: Write User HistoryDictionary: " + mLocale + ", "+ diff
|
||||
+ "ms. Total: " + profTotal + ". Insert: " + profInsert + ". Delete: "
|
||||
+ profDelete);
|
||||
}
|
||||
db.setTransactionSuccessful();
|
||||
return null;
|
||||
}
|
||||
|
||||
private static ContentValues getContentValues(String word1, String word2, String locale) {
|
||||
|
|
Loading…
Reference in New Issue