Motivation

When we call cursor.close will trigger cursor info persistent, there are two steps to persistence( ensure as little data loss as possible ):

• try to persist to Bookie
• if Bookie doesn't work, try to persist to ZK

Here's how we want it to work:

1. change state to closing
2. try to persist to BK
3. if Bookie doesn't work, try to persist to ZK
4. change state to closed

(High light)But there's something wrong with this code, here's how it exactly works:

1. change state to closing
2. try to persist to BK
3. (High light) race condition
   3-1. if Bookie doesn't work, try to persist to ZK. (High light) this command asynchronously works on thread bk client worker, and will fail caused of cursor state check(see code below).
   3-2. change state to closed

Modifications

Make change cursor state to closing always be executed after persistence

Documentation

• doc-required

• doc-not-needed

• doc

• doc-complete