pymongo 中的 Tailable 游标似乎已停止工作

Question

我已经成功地在 Pymongo 中使用可尾游标 2 年了，没有任何障碍，但是突然之间，今天，我的相同代码抛出了一个 "unexpected keyword" 错误：

几周前我升级到 3.0 Mongo，它仍然工作正常，但也许新的 pymongo 版本现在与我今天刚安装的新版本 (3.0.1) 不同？以前是pymongo 2.6.3。我的代码：

cursor = refreq.find(tailable = True, await_data = True)
while cursor.alive:
    xxx

所以基本上只要有东西被插入到 refreq 集合中，我就想知道它，而无需轮询。过去工作正常。最近安装了 Pymongo 3.0.1 版（今天）。

也尝试输入一个空字典

cursor = refreq.find({}, tailable = True, await_data = True)

但仍然给出相同的错误。有什么变化吗？

这里是完整的线程代码，供参考：

def handleRefRequests(db, refqueue):
    """ handles reference data requests. It's threaded. Needs the database id. 
    will create a capped collection and constantly poll it for new requests"""
    print("Dropping the reference requests collection")
    db.drop_collection("bbrefrequests")
    print("Recreating the reference requests collection")
    db.create_collection("bbrefrequests", capped = True, size = 100 * 1000000) # x * megabytes
    refreq = db.bbrefrequests
    # insert a dummy record otherwise exits immediately
    refreq.insert({"tickers":"test", "fields":"test", "overfields":"test", "overvalues":"test", "done": False})
    cursor = refreq.find({}, tailable = True, await_data = True)
    while cursor.alive:
        try:
            post = cursor.next()
            if ("tickers" in post) and ("fields" in post) and ("done" in post): # making sure request is well formed
                if post["tickers"] != "test":
                    refqueue.put(post)
        except StopIteration:
            time.sleep(0.1)
        if not runThreads:
            print("Exiting handleRefRequests thread")
            break

Answer 1

在 pymongo 3.0 中，find 为此采用了 cursor_type 选项。 tailable 和 await_data 参数已被删除。

所以应该是：

cursor = refreq.find(cursor_type = CursorType.TAILABLE_AWAIT)

pymongo 中的 Tailable 游标似乎已停止工作

Tailable cursor in pymongo seems to have stopped working

python

mongodb

pymongo