Application Continuity Checking for Application Continuity allows you to deploy Application Continuity easily and transparently.
2.3.1 Overview of Application Continuity
Oracle ORAchk identifies any references to deprecated JDNVC concrete classes that need to be changed.
Oracle ORAchk analyzes the database operations in the application and reports the level of protection. It also reports where and why the applications are not protected.
Together, these checks can help you ensure that your application workload is covered by Oracle Application Continuity.
2.3.2 Checks for Application Continuity
Application Continuity Checking for Concrete Classes
Determine whether Java applications use deprecated Oracle JDBC concrete classes.
To use Application Continuity with Java, replace the deprecated Oracle JDBC concrete classes. For information about the deprecation of concrete classes including actions to take if an application uses them, see My Oracle Support Note 1364193.1.
To know if the application is using concrete classes, use Application Continuity checking (called
acchk in Oracle ORAchk). There is no need to use 12c driver or database, or to have source code for concrete class checks. Verify the application in advance while planning for high availability for your application.
Application Continuity is unable to replay transactions that use
oracle.sql deprecated concrete classes of the form
STRUCT as a variable type, a cast, the return type of a method, or calling a constructor.
Modify them for Application Continuity to work with the application.
Table 2-1 Application Continuity Checking for Concrete Classes
|Command-Line Argument||Shell Environment Variable||Usage|
This must point to a version of
This must point to the
To analyze the application code for references to Oracle concrete classes, this must point to the parent directory name for the code. The program analyzes
Example Application Continuity Concrete Class Checks Summary
The following command checks the Application Continuity checking for Oracle concrete classes.
$ ./orachk -acchk -asmhome
Outage Type Status Message Concrete class checks Total : 19845 Passed : 19610 Warning : 0 Failed : 235 (Failed check count is one per file) FAILED [oracle/jdbc/driver/ArrayDataResultSet] [[CAST]desc= oracle/sql/STRUCT method name=getObject, lineno=1477] FAILED [oracle/jdbc/driver/ArrayDataResultSet] [[CAST]desc= oracle/sql/NCLOB method name=getNClob, lineno=1776] FAILED [oracle/jdbc/driver/BfileAccessor] [[Method]name=getBFILE, desc=(I)Loracle/sql/BFILE;, lineno=99] FAILED [oracle/jdbc/driver/BlobAccessor] [[Method]name=getBLOB, desc=(I)Loracle/sql/BLOB;, lineno=129] FAILED [oracle/jdbc/driver/ClobAccessor] [[Method]name=getCLOB_, desc=(I[B)Loracle/sql/CLOB;, lineno=230] FAILED [oracle/jdbc/driver/ClobAccessor] [[Method] name=getCLOB, desc=(I)Loracle/sql/CLOB;, lineno=226]
Application Continuity Checking for the Protection Level Application Continuity is Providing Your Application
Destructive testing is a good thing to do. However, introducing failures is non-deterministic. The application can fail over in all the tests, and then in production a failure occurs elsewhere and unexpectedly some requests do not fail over.
Using AC Check Coverage Analysis averts this situation by reporting in advance the percentage of requests that are fully protected by Application Continuity, and for the requests that are not fully protected, which they are and where. Use the coverage check before deployment, and the after application changes. Developers and management know how protected an application release is from failures of the underlying infrastructure. If there is a problem, then it can be fixed before the application is released or waived knowing the level of coverage.
Executing the coverage check is rather like using
SQL_TRACE. First run the application in a representative test environment with Application Continuity trace turned on at the server side. The trace is collected in the standard database user trace directory in user trace files. Then, pass this directory as input to Oracle ORAchk to report the coverage for the application functions that were run. As this check uses Application Continuity, the database and client must be using 12c. The application need not necessarily released with Application Continuity. The check is to help you release.
The following is a summary of the coverage analysis.
If a round trip is made to the database server and returns while Application Continuity’ capture is enabled during capture phase, then it is counted as a protected call.
If a round trip is made to the database server while Application Continuity’ capture is disabled (not in a request, or following a restricted call or a disable replay API was called), then it is counted as an unprotected call.
Round trips ignored by capture and replay are ignored in the protection-level statistics.
At the end of processing each trace file, a level of protection for the calls sent to the database is computed.
For each trace:
PASS (>= 75),
WARNING (25 <= value <75), and
FAIL (< 25)
Running the Coverage Report
Turn on tracing at either a session level or database level.To enable for a single application function, run as follows (put this statement in the callback or before
beginRequestso replay is not disabled by setting events):
alter session set events 'trace [progint_appcont_rdbms]';To enable for all sessions, run as follows:
alter system set event='trace[progint_appcont_rdbms]' scope = spfile;
Run through the application functions. To report on an application function, the application function must be run. The more application functions run, the better the information that the coverage analysis provides.
Use Oracle ORAchk to analyze the collected database traces and report the level of protection, and where not protected, reports why a request is not protected.
To control the Application Continuity checking for coverage, set the following four values through command line or shell environment variables (or mixed):
Table 2-2 Using Application Continuity Checking for Protection Level
Command-Line Argument Shell Environment Variable Usage
This must point to a version of
asm-all-5.0.3.jarthat you download from ASM Home Page.
This must point to the
JAVA_HOMEdirectory for a JDK8 installation.
RAT_AC_TRCDIRTo analyze the coverage, specify a directory name that contains one or more database server trace files. The trace directory is generally,
When scanning the trace directory, this optional value limits the analysis to scanning to files created in the most recent specified number of days
Example Coverage Report
$ ./orachk -asmhome /tmp/asm-all-5.0.3.jar -javahome /tmp/jdk1.8.0_40 -apptrc $ORACLE_BASE/diag/rdbms/$ORACLE_SID/trace 3
Reading the Coverage Report
The coverage check produces a directory named
orachk_uname_date_time. This report summaries coverage and lists trace files that have WARNINGS or FAIL status. To ensure all requests PASS (Coverage(%) = 100), check the PASS report,
acchk_scorecard_pass.html in the reports directory. To see all the details, look for
reports/acchk_scorecard_pass.html under the
The output includes the database service name, the module name (from
v$session.program, which can be set on the client side using the connection property on Java, for example,
CLIENT_ID, which can be set using
Outage Type Status/Message Coverage checks Total : 19845 Passed : 19610 Warning : 0 Failed : 235 (Failed check count is one per file) [FAIL] Trace file name = SAMPLE_ora_1234.trc Row number = 2222 SERVICE NAME = (SAMPLE_WEB_SERVICE.OCS.QA) MODULE NAME = (DEBIT) ACTION NAME = null CLIENT ID = null Coverage(%) = 50 ProtectedCalls = 4 UnProtectedCalls = 4 [FAIL] Trace file name = SAMPLE_ora_5678.trc Row number = 7653 SERVICE NAME = (SAMPLE_WEB_SERVICE.OCS.QA) MODULE NAME = (PAYMENTS) ACTION NAME = null CLIENT ID = null Coverage(%) = 20 ProtectedCalls = 1 UnProtectedCalls = 4 [FAIL] Trace file name = SAMPLE_ora_90123.trc Row number = 15099 SERVICE NAME = (SAMPLE_WEB_SERVICE.OCS.QA) MODULE NAME = (PAYMENTS) ACTION NAME = null CLIENT ID = null Coverage(%) = 60 ProtectedCalls = 3 UnProtectedCalls = 2 [FAIL] Trace file name = SAMPLE_ora_4747.trc Row number = 789 SERVICE NAME = (SAMPLE_WEB_SERVICE.OCS.QA) MODULE NAME = (ACCOUNT) ACTION NAME = null CLIENT ID = null Coverage(%) = 50 ProtectedCalls = 2 UnProtectedCalls = 2