发布于 2015-09-14 15:07:17 | 238 次阅读 | 评论: 0 | 来源: 网络整理
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getLastError
The getLastError command returns the error status of
the last operation on the current connection. By default MongoDB
does not provide a response to confirm the success or failure of a
write operation, clients typically use getLastError in
combination with write operations to ensure that the write
succeeds.
Consider the following prototype form.
The following options are available:
| 参数: |
- j (boolean) – If true, wait for the next journal commit
before returning, rather than a full disk
flush. If mongod does not have
journaling enabled, this option has no effect.
- w – When running with replication, this is the number of
servers to replicate to before returning. A w value of
1 indicates the primary only. A w value of 2
includes the primary and at least one secondary, etc.
In place of a number, you may also set w to
majority to indicate that the command should wait
until the latest write propagates to a majority of
replica set members. If using w, you should also use
wtimeout. Specifying a value for w without also
providing a wtimeout may cause
getLastError to block indefinitely.
- fsync (boolean) – If true, wait for mongod to write this
data to disk before returning. Defaults to
false. In most cases, use the j option
to ensure durability and consistency of the
data set.
- wtimeout (integer) – Optional. Milliseconds. Specify a value in
milliseconds to control how long to
wait for write propagation to complete. If
replication does not complete in the given
timeframe, the getLastError
command will return with an error status.
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