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https://issues.apache.org/jira/browse/DERBY-6066?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Mamta A. Satoor updated DERBY-6066:
-----------------------------------
Attachment: DERBY6066_patch1_diff.txt
The attached patch has the changes to use PreparedStatement rather than
Statement to get the transaction isolation level.
This is similar to what we did for set tranaction isolation level as part of
DERBY-6053.
But I noticed that my changes do not get run (I put a System.out.println inside
the changes to see if it got printed when running derbyall and junit suite and
the println never got printed) when I ask for get transaction isolation level
or when I run the derbyall and junit suite. I found that this is because of the
checkin that went in as part of DERBY-2084 which gets the current isolation
level piggy backed as part of some other communication happening between cient
and server and because of that get transaction isolation call on the client
side does not need to go over the line to the server to find the current
isolation. Copying below the piece of code(from
o.a.d.client.am.Connection.getTransactionIsolationX) where we take advantage of
isolation level picked from piggbacking
if (isolation_ != TRANSACTION_UNKNOWN) {
if (SanityManager.DEBUG) {
SanityManager.ASSERT(supportsSessionDataCaching(),
"Cannot return cached isolation when caching is " +
"not supported!");
}
return isolation_;
}
Just for testing my code changes, I commented out the code above(this will
require us to send get isolation level on the wire to the server everytime
client asks for it) and added the println in my changes and ran the tests again
and I see that we spit out the println when get transaction isolation level is
requested by the user. This verifies that my changes are working fine. The
attached patch obviosuly doesn't have the println and it does not comment out
the piggybacking isolation level usage
if (getTransactionIsolationPrepStmt == null ||
!getTransactionIsolationPrepStmt.openOnClient_) {
System.out.println("came in new code");
getTransactionIsolationPrepStmt =
prepareStatementX(
"VALUES CURRENT ISOLATION",
java.sql.ResultSet.TYPE_FORWARD_ONLY,
java.sql.ResultSet.CONCUR_READ_ONLY,
holdability(),
java.sql.Statement.NO_GENERATED_KEYS,
null, null);
}
So the usage of prepared statement rather than statement for get transaction
isolation will not improve the performance by a lot since we do not send these
calls on the wire so much but I think it is still a good change. If there are
no objections to this change, I will go ahead and commit it in couple days
> Client should use a prepared statement rather than regular statement for
> Connection.getTransactionIsolation
> -----------------------------------------------------------------------------------------------------------
>
> Key: DERBY-6066
> URL: https://issues.apache.org/jira/browse/DERBY-6066
> Project: Derby
> Issue Type: Improvement
> Components: Network Client
> Reporter: Mamta A. Satoor
> Assignee: Mamta A. Satoor
> Attachments: DERBY6066_patch1_diff.txt
>
>
> This jira is similar to DERBY-6053 but for
> o.a.d.client.am.Connection.getTransactionIsolation. Use prepared statement
> rather than regular statement every time user makes a get transaction
> isolation call.
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