问题描述

我有一个经常访问本地 sqlite3 数据库的 android 应用程序，出于性能考虑，所以我始终保持连接打开.但是我的一位朋友建议我每次操作都打开/关闭连接.

I have an android application that access local sqlite3 db frequently, for performance consideration so i always keep the connection open. But one of my friends recommended me to open/close the connection every operation.

1) 你们对这两种方法有什么看法?缺点/优点.2)我做了一些测试，发现数据库连接没有太多的性能开销.DB连接的性能开销是否因DB的大小而异?

1) What's your guys opinion on these two methods ? cons/pros. 2) I did some testing and find the DB connection doesn't have too much perf overhead. Does the performance overhead of DB connection varies on the size of the DB ?

推荐答案

我不知道频繁关闭/打开数据库(无论其大小)有什么性能损失.我认为这个问题的答案还取决于访问数据库的应用程序类型.

I don't know of any performance penalties in frequent closing/opening of the database (regardless of its size). I think the answer to this question also depends on what type of application is accessing the database.

您是否经常重新查询"数据库?
然后它似乎纠正了保持打开状态.

Do you "re-query" the database a lot?
Then it seems rectified to keep it open.

每次获取数据时是否获取不同的数据?
同样，将其保持打开状态似乎是合理的(因为您不会获得缓存数据的好处).

Do you fetch different data each time you fetch something?
Again, it seems reasonable to leave it open (as you won't gain in caching the data instead).

是否有其他应用程序访问同一数据库?
如果存在并发或阻塞问题的风险，在完成读取/写入数据库后关闭数据库可能是明智之举.

Are there any other applications accessing the same database?
If there is a risk for concurrency or blocking issues, it might be wise to close the database after finished reading/writing from/to it.

通常我会说，在优化性能时，缓存数据可能比保持数据库打开(相反关闭它)获得更多.

Generally I would say that you might gain more in caching data than in leaving the database open (contra closing it) when optimizing for performance.

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