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From: Lars George <lars.george@gmail.com>
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Subject: HTable thread safe for scans?
Message-Id: <88552E7E-5486-4185-8FDA-0C9438C5EAB6@gmail.com>
Date: Mon, 15 Jul 2013 10:02:16 +0200
To: "dev@hbase.apache.org" <dev@hbase.apache.org>
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Hi,

Please see =
https://issues.apache.org/jira/browse/HBASE-7035#comment-13708295 for =
context. We added a while ago some wording around why HTable is not =
thread safe and how you should use HTablePool instead. I do get the =
point about the local write buffer, and also maybe if you do Get's or =
any Batch/Multi operation. But what about scans? I mean, looking at the =
code, it does not seem to be interfering with HTable at all, it gets =
handed in the connection reference (the ClientScanner) and since after =
that it has its own ID based counterpart on the server side, it seems =
that the thread which created the scan is safe to release the table =
instance to the pool again.

In other words, if a thread (#1) creates a scanner, then another thread =
(#2) is allowed to use the table instance used by the first thread, =
would thread #1 have any issues with using the already created scanner? =
I'd say no, reading the code.=20

If that is the case, we should fix the JavaDoc.

Lars=

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