Android Sqlite ANR 问题解决及其事物处理 -- waiting on (a java.lang.VMThread) held by tid=1 (main)

错误日志

The connection pool for database '/data/data/com.meelive.ingkee/databases/Ingkee45997756' has been unable to grant a connection to thread 1 (main) with flags 0x5 for 30.000002 seconds.
Connections: 0 active, 1 idle, 0 available.

"main" prio=5 tid=1 ·
| group="main" sCount=1 dsCount=0 obj=0x41ad2de0 self=0x41a86130
| sysTid=3866 nice=0 sched=0/0 cgrp=default handle=1074348420
| state=S schedstat=( 22153833728 1885119937 37454 ) utm=1925 stm=290 core=0
at java.lang.Object.wait(Native Method)
- waiting on <0x41ad2eb0> (a java.lang.VMThread) held by tid=1 (main)
at java.lang.Thread.parkFor(Thread.java:1212)
at sun.misc.Unsafe.park(Unsafe.java:325)
at java.util.concurrent.locks.LockSupport.parkNanos(LockSupport.java:197)
at android.database.sqlite.SQLiteConnectionPool.waitForConnection(SQLiteConnectionPool.java:672)
at android.database.sqlite.SQLiteConnectionPool.acquireConnection(SQLiteConnectionPool.java:348)
at android.database.sqlite.SQLiteSession.acquireConnection(SQLiteSession.java:894)
at android.database.sqlite.SQLiteSession.prepare(SQLiteSession.java:586)
at android.database.sqlite.SQLiteProgram.<init>(SQLiteProgram.java:58)
at android.database.sqlite.SQLiteQuery.<init>(SQLiteQuery.java:37)
at android.database.sqlite.SQLiteDirectCursorDriver.query(SQLiteDirectCursorDriver.java:44)
at android.database.sqlite.SQLiteDatabase.rawQueryWithFactory(SQLiteDatabase.java:1364)
at android.database.sqlite.SQLiteDatabase.rawQuery(SQLiteDatabase.java:1303)
at com.meelive.ingkee.db.a.c(ContactDao.java:100)
at com.***.***.v1.chat.model.chat.k.b(JsonToBean.java:157)
at com.***.***.v1.chat.model.chat.e$b.a(ChatEventManagerImpl.java:558)
at com.loopj.android.http.q.a(TextHttpResponseHandler.java:98)
at com.loopj.android.http.c.a(AsyncHttpResponseHandler.java:371)
at com.loopj.android.http.c$a.handleMessage(AsyncHttpResponseHandler.java:195)
at android.os.Handler.dispatchMessage(Handler.java:110)
at android.os.Looper.loop(Looper.java:193)
at android.app.ActivityThread.main(ActivityThread.java:5468)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:515)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:860)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:676)
at dalvik.system.NativeStart.main(Native Method)

1、数据库要去请求锁 但是VMThread持有着 所以在等待

2、beginTransaction();…1…execSQL(sql);….2……endTransaction(); 在2初又执行了查询数据库操作引起的。

解决方法：在endTransaction();后再执行查询操作

stackoverflow 相关问题

这是原来的数据库操作代码

try {
-            DbManager.getInstance().db.beginTransaction();
for (int i = 0; i < list.size(); i++) {
DbManager.getInstance().db.execSQL("delete from " + FEED_LOCAL_VIDEO_TABLE + " where id=" + list.get(i).id);
}
DbManager.getInstance().db.setTransactionSuccessful();
-            DbManager.getInstance().db.endTransaction();
} catch (Exception e) {
e.printStackTrace();
}

下面说一下SQLite中的事物处理

使用SQLiteDatabase的beginTransaction()方法可以开启一个事务，程序执行到endTransaction()

方法时会检查事务的标志是否为成功，如果程序执行到endTransaction()之前调用了setTransactionSuccessful()

方法设置事务的标志为成功则提交事务，如果没有调用setTransactionSuccessful()

方法则回滚事务。事务处理应用：很多时候我们需要批量的向Sqlite中插入大量数据时，单独的使用添加方法导致应用响应缓慢,

因为sqlite插入数据的时候默认一条语句就是一个事务，有多少条数据就有多少次磁盘操作。如初始8000条记录也就是要8000次读写磁盘操作。同时也是为了保证数据的一致性，避免出现数据缺失等情况。

下面是正确的使用方法

SQLiteDatabase db = dbOpenHelper.getWritableDatabase();

//开启事务
db.beginTransaction();
try{
//批量处理操作
//do something
db.execSQL("SQL语句", new Object[]{});
db.execSQL("SQL语句", new Object[]{});
//设置事务标志为成功，当结束事务时就会提交事务
db.setTransactionSuccessful();
}
catch(Exception e){

}

finally{
//结束事务
db.endTransaction();
}

上面的代码修改如下

+        DbManager.getInstance().db.beginTransaction();
try {
for (int i = 0; i < list.size(); i++) {
DbManager.getInstance().db.execSQL("delete from " + FEED_USER_INFO_TABLE + " where uid=" + list.get(i).uid);
}
DbManager.getInstance().db.setTransactionSuccessful();
} catch (Exception e) {
e.printStackTrace();
return null;
+        }finally {
+            DbManager.getInstance().db.endTransaction();
}