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6 Monitoring XStream Out

This chapter provides instructions for monitoring XStream.

This chapter contains these topics:

Note:

Whenever possible, this chapter uses ALL_ static data dictionary views for query examples. In some cases, information in the ALL_ views is more limited than the information in the DBA_ views.

About Monitoring XStream Out

This chapter describes monitoring an XStream Out configuration and an XStream In configuration. This chapter provides instructions for querying data dictionary views related to XStream. The queries provide information about XStream components and statistics related to XStream.

The main interface for monitoring XStream database components is SQL*Plus, although you can monitor some aspects of an XStream configuring using Oracle Enterprise Manager Cloud Control. For example, you can view information about capture processes, outbound servers, inbound servers, and rules in Oracle Enterprise Manager Cloud Control.

In SQL*Plus, trusted XStream administrators can query the ALL_ and DBA_ views. Untrusted XStream administrators can query the ALL_ views only.

This chapter also describes using the Oracle Streams Performance Advisor to monitor an XStream configuration. The Oracle Streams Performance Advisor consists of the DBMS_STREAMS_ADVISOR_ADM package and a collection of data dictionary views. The Oracle Streams Performance Advisor enables you to monitor the topology and performance of an XStream environment.

Monitoring Session Information About XStream Out Components

The query in this section displays the following session information about each XStream component in a database:

  • The XStream component name

  • The session identifier

  • The serial number

  • The operating system process identification number

  • The XStream program name

This query is especially useful for determining the session information for specific XStream components when there are multiple XStream Out components configured in a database.

To display this information for each XStream component in a database: 

  1. Connect to the database as the XStream administrator.

    See Oracle Database Administrator's Guide for information about connecting to a database in SQL*Plus.

  2. Run the following query:

    COLUMN ACTION HEADING 'XStream Component' FORMAT A30
    COLUMN SID HEADING 'Session ID' FORMAT 99999
    COLUMN SERIAL# HEADING 'Session|Serial|Number' FORMAT 99999999
    COLUMN PROCESS HEADING 'Operating System|Process ID' FORMAT A17
    COLUMN PROCESS_NAME HEADING 'XStream|Program|Name' FORMAT A7
     
    SELECT /*+PARAM('_module_action_old_length',0)*/ ACTION,
           SID,
           SERIAL#,
           PROCESS,
           SUBSTR(PROGRAM,INSTR(PROGRAM,'(')+1,4) PROCESS_NAME
      FROM V$SESSION
      WHERE MODULE ='XStream';
    
    
    

Your output for an XStream Out configuration looks similar to the following:

                                            Session                   XStream
                                             Serial Operating System  Program
XStream Component              Session ID    Number Process ID        Name
------------------------------ ---------- --------- ----------------- -------
XOUT - Apply Coordinator               21         9 27222             AP01
CAP$_XOUT_18 - Capture                 28        33 27248             CP01
XOUT - Apply Server                    97        43 27226             AS00
XOUT - Apply Reader                   105         5 27224             AS01
XOUT - Apply Server                   112        27 27342             TNS
XOUT - Propagation Send/Rcv           117         5 27250             CS00

The row that shows TNS for the XStream program name contains information about the session for the XStream client application that is attached to the outbound server.

See Also:

Oracle Database Reference for more information about the V$SESSION view

Monitoring XStream Out

This section provides sample queries that you can use to monitor XStream Out.

This section contains these topics:

With XStream Out, an Oracle Streams apply process functions as an outbound server. Therefore, you can also use the data dictionary views for apply processes to monitor outbound servers. In addition, an XStream Out environment includes capture processes and queues, and might include other components, such as propagations, rules, and rule-based transformations.

Displaying General Information About an Outbound Server

You can display the following information for an outbound server by running the query in this section:

  • The outbound server name

  • The name of the connect user for the outbound server

    The connect user is the user who can attach to the outbound server to retrieve the logical change record (LCR) stream. The client application must attach to the outbound server as the specified connect user.

  • The name of the capture user for the capture process that captures changes for the outbound server to process

  • The name of the capture process that captures changes for the outbound server to process

  • The name of the source database for the captured changes

  • The owner of the queue used by the outbound server

  • The name of the queue used by the outbound server

The ALL_XSTREAM_OUTBOUND view contains information about the capture user, the capture process, and the source database in either of the following cases:

  • The outbound server was created using the CREATE_OUTBOUND procedure in the DBMS_XSTREAM_ADM package.

  • The outbound server was created using the ADD_OUTBOUND procedure in the DBMS_XSTREAM_ADM package, and the capture process for the outbound server runs on the same database as the outbound server.

If the outbound server was created using the ADD_OUTBOUND procedure, and the capture process for the outbound server is on a different database, then the ALL_XSTREAM_OUTBOUND view does not contain information about the capture user, the capture process, or the source database.

To display this general information about an outbound server: 

  1. Connect to the database as the XStream administrator.

    See Oracle Database Administrator's Guide for information about connecting to a database in SQL*Plus.

  2. Run the following query:

    COLUMN SERVER_NAME HEADING 'Outbound|Server|Name' FORMAT A10
    COLUMN CONNECT_USER HEADING 'Connect|User' FORMAT A10
    COLUMN CAPTURE_USER HEADING 'Capture|User' FORMAT A10
    COLUMN CAPTURE_NAME HEADING 'Capture|Process|Name' FORMAT A12
    COLUMN SOURCE_DATABASE HEADING 'Source|Database' FORMAT A11
    COLUMN QUEUE_OWNER HEADING 'Queue|Owner' FORMAT A10
    COLUMN QUEUE_NAME HEADING 'Queue|Name' FORMAT A10
    
    SELECT SERVER_NAME, 
           CONNECT_USER, 
           CAPTURE_USER, 
           CAPTURE_NAME,
           SOURCE_DATABASE,
           QUEUE_OWNER,
           QUEUE_NAME
      FROM ALL_XSTREAM_OUTBOUND;
    

Your output looks similar to the following:

Outbound                         Capture
Server     Connect    Capture    Process      Source      Queue      Queue
Name       User       User       Name         Database    Owner      Name
---------- ---------- ---------- ------------ ----------- ---------- ----------
XOUT       XSTRMADMIN XSTRMADMIN CAP$_XOUT_18 XOUT.EXAMPL XSTRMADMIN Q$_XOUT_19
                                              E.COM

Displaying Status and Error Information for an Outbound Server

The DBA_APPLY view shows XStream Out in the PURPOSE column for an apply process that is functioning as an outbound server.

To display detailed information about an outbound server: 

  1. Connect to the database as the XStream administrator.

    See Oracle Database Administrator's Guide for information about connecting to a database in SQL*Plus.

  2. Run the following query:

    COLUMN APPLY_NAME HEADING 'Outbound Server|Name' FORMAT A15
    COLUMN STATUS HEADING 'Status' FORMAT A8
    COLUMN ERROR_NUMBER HEADING 'Error Number' FORMAT 9999999
    COLUMN ERROR_MESSAGE HEADING 'Error Message' FORMAT A40
    
    SELECT APPLY_NAME, 
           STATUS,
           ERROR_NUMBER,
           ERROR_MESSAGE
      FROM DBA_APPLY
      WHERE PURPOSE = 'XStream Out';
    

Your output looks similar to the following:

Outbound Server
Name            Status   Error Number Error Message
--------------- -------- ------------ ----------------------------------------
XOUT            ENABLED

This output shows that XOUT is an apply process that is functioning as an outbound server.

Note:

This example queries the DBA_APPLY view. This view enables trusted users to see information for all apply users in the database. Untrusted users must query the ALL_APPLY view, which limits information to the current user.

Displaying Information About an Outbound Server's Current Transaction

The V$XSTREAM_OUTBOUND_SERVER view contains the following information about the transaction currently being processed by an XStream outbound server:

  • The name of the outbound server

  • The transaction ID of the transaction currently being processed

  • Commit system change number (SCN) of the transaction currently being processed

  • Commit position of the transaction currently being processed

  • The position of the last LCR sent to the XStream client application

  • The message number of the current LCR being processed by the outbound server

Run this query to determine how many LCRs an outbound server has processed in a specific transaction. You can query the TOTAL_MESSAGE_COUNT column in the V$XSTREAM_TRANSACTION view to determine the total number of LCRs in a transaction.

To display information about an outbound server's current transaction: 

  1. Connect to the database as the XStream administrator.

    See Oracle Database Administrator's Guide for information about connecting to a database in SQL*Plus.

  2. Run the following query:

    COLUMN SERVER_NAME HEADING 'Outbound|Server|Name' FORMAT A10
    COLUMN 'Transaction ID' HEADING 'Transaction|ID' FORMAT A11
    COLUMN COMMITSCN HEADING 'Commit SCN' FORMAT 9999999999999
    COLUMN COMMIT_POSITION HEADING 'Commit Position' FORMAT A15
    COLUMN LAST_SENT_POSITION HEADING 'Last Sent|Position' FORMAT A15
    COLUMN MESSAGE_SEQUENCE HEADING 'Message|Number' FORMAT 999999999
     
    SELECT SERVER_NAME,
           XIDUSN ||'.'|| 
           XIDSLT ||'.'||
           XIDSQN "Transaction ID",
           COMMITSCN,
           COMMIT_POSITION,
           LAST_SENT_POSITION,
           MESSAGE_SEQUENCE
      FROM V$XSTREAM_OUTBOUND_SERVER;
    

Your output looks similar to the following:

Outbound
Server     Transaction                                Last Sent          Message
Name       ID              Commit SCN Commit Position Position            Number
---------- ----------- -------------- --------------- --------------- ----------
XOUT       2.22.304            820023 0000000C82E4000 0000000C8337000        616
                                      000010000000100 000010000000100
                                      00000C82E400000 00000C833700000
                                      0010000000101   0010000000101

Note:

The COMMITSCN and COMMIT_POSITION values are populated only if the COMMITTED_DATA_ONLY value is YES in V$XSTREAM_OUTBOUND_SERVER.

Displaying Statistics for an Outbound Server

The V$XSTREAM_OUTBOUND_SERVER view contains the following statistics about the database changes processed by an XStream outbound server:

  • The name of the outbound server

  • The number of transactions sent from the outbound server to the XStream client application since the last time the client application attached to the outbound server

  • The number of LCRs sent from the outbound server to the XStream client application since the last time the client application attached to the outbound server

  • The number of megabytes sent from the outbound server to the XStream client application since the last time the client application attached to the outbound server

  • The amount of time the outbound server spent sending LCRs to the XStream client application since the last time the client application attached to the outbound server

  • The message number of the last LCR sent by the outbound server to the XStream client application

  • Creation time at the source database of the last LCR sent by the outbound server to the client application

To display statistics for an outbound server: 

  1. Connect to the database as the XStream administrator.

    See Oracle Database Administrator's Guide for information about connecting to a database in SQL*Plus.

  2. Run the following query:

    COLUMN SERVER_NAME HEADING 'Outbound|Server|Name' FORMAT A8
    COLUMN TOTAL_TRANSACTIONS_SENT HEADING 'Total|Trans|Sent' FORMAT 9999999
    COLUMN TOTAL_MESSAGES_SENT HEADING 'Total|LCRs|Sent' FORMAT 9999999999
    COLUMN BYTES_SENT HEADING 'Total|MB|Sent' FORMAT 99999999999999
    COLUMN ELAPSED_SEND_TIME HEADING 'Time|Sending|LCRs|(in seconds)' FORMAT 99999999
    COLUMN LAST_SENT_MESSAGE_NUMBER HEADING 'Last|Sent|Message|Number' FORMAT 99999999
    COLUMN LAST_SENT_MESSAGE_CREATE_TIME HEADING 'Last|Sent|Message|Creation|Time' FORMAT A9
     
    SELECT SERVER_NAME,
           TOTAL_TRANSACTIONS_SENT,
           TOTAL_MESSAGES_SENT,
           (BYTES_SENT/1024)/1024 BYTES_SENT,
           (ELAPSED_SEND_TIME/100) ELAPSED_SEND_TIME,
           LAST_SENT_MESSAGE_NUMBER,
           TO_CHAR(LAST_SENT_MESSAGE_CREATE_TIME,'HH24:MI:SS MM/DD/YY') 
              LAST_SENT_MESSAGE_CREATE_TIME
      FROM V$XSTREAM_OUTBOUND_SERVER;
    

Your output looks similar to the following:

                                                                     Last
                                                      Time      Last Sent
Outbound    Total       Total           Total      Sending      Sent Message
Server      Trans        LCRs              MB         LCRs   Message Creation
Name         Sent        Sent            Sent (in seconds)    Number Time
-------- -------- ----------- --------------- ------------ --------- ---------
XOUT         4028      256632              67            1    820023 10:11:00
                                                                     02/28/11

Note:

The TOTAL_TRANSACTIONS_SENT value is populated only if the COMMITTED_DATA_ONLY value is YES in V$XSTREAM_OUTBOUND_SERVER.

Displaying the Processed Low Position for an Outbound Server

For an outbound server, the processed low position is the position below which all transactions have been committed and logged by the client application. The processed low position is important when the outbound server or the client application is restarted.

You can display the following information about the processed low position for an outbound server by running the query in this section:

  • The outbound server name

  • The name of the source database for the captured changes

  • The processed low position, which indicates the low watermark position processed by the client application

  • The time when the processed low position was last updated by the outbound server

To display the processed low position for an outbound server: 

  1. Connect to the database as the XStream administrator.

    See Oracle Database Administrator's Guide for information about connecting to a database in SQL*Plus.

  2. Run the following query:

    COLUMN SERVER_NAME HEADING 'Outbound|Server|Name' FORMAT A10
    COLUMN SOURCE_DATABASE HEADING 'Source|Database' FORMAT A20
    COLUMN PROCESSED_LOW_POSITION HEADING 'Processed|Low LCR|Position' FORMAT A30
    COLUMN PROCESSED_LOW_TIME HEADING 'Processed|Low|Time' FORMAT A9
    
    SELECT SERVER_NAME,
           SOURCE_DATABASE,
           PROCESSED_LOW_POSITION,
           TO_CHAR(PROCESSED_LOW_TIME,'HH24:MI:SS MM/DD/YY') PROCESSED_LOW_TIME
    FROM ALL_XSTREAM_OUTBOUND_PROGRESS; 
    

Your output looks similar to the following:

Outbound                        Processed                      Processed
Server     Source               Low LCR                        Low
Name       Database             Position                       Time
---------- -------------------- ------------------------------ ---------
XOUT       XOUT.EXAMPLE.COM     0000000C84EA000000000000000000 10:18:37
                                00000C84EA000000000000000001   02/28/11

Determining the Process Information for an Outbound Server

An outbound server is an Oracle background process. This background process runs only when an XStream client application attaches to the outbound server. The V$XSTREAM_OUTBOUND_SERVER view contains information about this background process.

You can display the following information for an outbound server by running the query in this section:

  • The outbound server name

  • The session ID of the outbound server's session

  • The serial number of the outbound server's session

  • The process identification number of the operating-system process that sends LCRs to the client application

To display the process information for an outbound server: 

  1. Connect to the database as the XStream administrator.

    See Oracle Database Administrator's Guide for information about connecting to a database in SQL*Plus.

  2. Run the following query:

    COLUMN SERVER_NAME HEADING 'Outbound Server Name' FORMAT A20
    COLUMN SID HEADING 'Session ID' FORMAT 9999999999
    COLUMN SERIAL# HEADING 'Serial Number' FORMAT 9999999999
    COLUMN SPID HEADING 'Operating-System Process' FORMAT A25
    
    SELECT SERVER_NAME, 
           SID, 
           SERIAL#, 
           SPID
      FROM V$XSTREAM_OUTBOUND_SERVER;
    

Your output looks similar to the following:

Outbound Server Name  Session ID Serial Number Operating-System Process
-------------------- ----------- ------------- -------------------------
XOUT                          18            19 15906

Note:

The V$XSTREAM_APPLY_SERVER view provides additional information about the outbound server process, and information about the apply server background processes used by the outbound server.

Displaying the Apply Parameter Settings for an Outbound Server

Apply parameters determine how an outbound server operates.

To display the apply parameter settings for an outbound server: 

  1. Connect to the database as the XStream administrator.

    See Oracle Database Administrator's Guide for information about connecting to a database in SQL*Plus.

  2. Run the following query:

    COLUMN APPLY_NAME HEADING 'Outbound Server|Name' FORMAT A15
    COLUMN PARAMETER HEADING 'Parameter' FORMAT A30
    COLUMN VALUE HEADING 'Value' FORMAT A22
    COLUMN SET_BY_USER HEADING 'Set by|User?' FORMAT A10
     
    SELECT APPLY_NAME,
           PARAMETER, 
           VALUE,
           SET_BY_USER  
      FROM ALL_APPLY_PARAMETERS a, ALL_XSTREAM_OUTBOUND o
      WHERE a.APPLY_NAME=o.SERVER_NAME
      ORDER BY a.PARAMETER;
    

Your output looks similar to the following:

Outbound Server                                                       Set by
Name            Parameter                      Value                  User?
--------------- ------------------------------ ---------------------- ----------
XOUT            ALLOW_DUPLICATE_ROWS           N                      NO
XOUT            APPLY_SEQUENCE_NEXTVAL         Y                      NO
XOUT            COMMIT_SERIALIZATION           DEPENDENT_TRANSACTIONS NO
XOUT            COMPARE_KEY_ONLY               N                      NO
XOUT            COMPUTE_LCR_DEP_ON_ARRIVAL     N                      NO
XOUT            DISABLE_ON_ERROR               Y                      NO
XOUT            DISABLE_ON_LIMIT               N                      NO
XOUT            EAGER_SIZE                     9500                   NO
XOUT            ENABLE_XSTREAM_TABLE_STATS     Y                      NO
XOUT            EXCLUDETAG                                            NO
XOUT            EXCLUDETRANS                                          NO
XOUT            EXCLUDEUSER                                           NO
XOUT            EXCLUDEUSERID                                         NO
XOUT            GETAPPLOPS                     Y                      NO
XOUT            GETREPLICATES                  N                      NO
XOUT            GROUPTRANSOPS                  10000                  NO
XOUT            HANDLECOLLISIONS               N                      NO
XOUT            IGNORE_TRANSACTION                                    NO
XOUT            MAXIMUM_SCN                    INFINITE               NO
XOUT            MAX_PARALLELISM                1                      NO
XOUT            MAX_SGA_SIZE                   INFINITE               NO
XOUT            OPTIMIZE_PROGRESS_TABLE        Y                      NO
XOUT            OPTIMIZE_SELF_UPDATES          Y                      NO
XOUT            PARALLELISM                    1                      NO
XOUT            PRESERVE_ENCRYPTION            Y                      NO
XOUT            RTRIM_ON_IMPLICIT_CONVERSION   Y                      NO
XOUT            STARTUP_SECONDS                0                      NO
XOUT            SUPPRESSTRIGGERS               Y                      NO
XOUT            TIME_LIMIT                     INFINITE               NO
XOUT            TRACE_LEVEL                    0                      NO
XOUT            TRANSACTION_LIMIT              INFINITE               NO
XOUT            TXN_AGE_SPILL_THRESHOLD        900                    NO
XOUT            TXN_LCR_SPILL_THRESHOLD        10000                  NO
XOUT            WRITE_ALERT_LOG                Y                      NO

Outbound servers ignore some apply parameter settings. See Oracle Database PL/SQL Packages and Types Reference for information about these apply parameters.

Note:

If the Set by User? column is NO for a parameter, then the parameter is set to its default value. If the Set by User? column is YES for a parameter, then the parameter was set by a user and might or might not be set to its default value.

Monitoring the Capture Process for an Outbound Server

This section provides sample queries that you can use to monitor the capture process for an outbound server.

This section contains these topics:

See Also:

Oracle Streams Concepts and Administration includes more queries that you can use to monitor a capture process

Displaying Change Capture Information About Each Capture Process

The query in this section displays the following information about each capture process in a database:

  • The name of the capture process.

  • The current state of the capture process

    See "Capture Process States".

  • The total number of redo entries passed by LogMiner to the capture process for detailed rule evaluation. A capture process converts a redo entry into an LCR and performs detailed rule evaluation on the LCR when capture process prefiltering cannot discard the change.

  • The total number LCRs enqueued since the capture process was last started.

To display this change capture information about each capture process in a database: 

  1. Connect to the database as the XStream administrator.

    See Oracle Database Administrator's Guide for information about connecting to a database in SQL*Plus.

  2. Run the following query:

    COLUMN CAPTURE_NAME HEADING 'Capture|Name' FORMAT A15
    COLUMN STATE HEADING 'State' FORMAT A25
    COLUMN TOTAL_MESSAGES_CAPTURED HEADING 'Redo|Entries|Evaluated|In Detail' FORMAT 99999999999999
    COLUMN TOTAL_MESSAGES_ENQUEUED HEADING 'Total|LCRs|Enqueued' FORMAT 99999999999999
    
    SELECT CAPTURE_NAME,
           STATE,
           TOTAL_MESSAGES_CAPTURED,
           TOTAL_MESSAGES_ENQUEUED 
      FROM V$XSTREAM_CAPTURE;
    

Your output looks similar to the following:

                                                     Redo
                                                  Entries           Total
Capture                                         Evaluated            LCRs
Name            State                           In Detail        Enqueued
--------------- ------------------------- --------------- ---------------
CAP$_XOUT_1     WAITING FOR TRANSACTION            297666          261798

The number of redo entries scanned can be higher than the number of DML and DDL redo entries captured by a capture process. Only DML and DDL redo entries that satisfy the rule sets of a capture process are captured and sent to an outbound server. Also, the total LCRs enqueued includes LCRs that contain transaction control statements. These row LCRs contain directives such as COMMIT and ROLLBACK. Therefore, the total LCRs enqueued is a number higher than the number of row changes and DDL changes enqueued by a capture process.

See Also:

"Row LCRs" for more information about transaction control statements

Displaying the Registered Redo Log Files for Each Capture Process

You can display information about the archived redo log files that are registered for each capture process in a database by running the query in this section. This query displays information about these files for both local capture processes and downstream capture processes.

The query displays the following information for each registered archived redo log file:

  • The name of a capture process that uses the file

  • The source database of the file

  • The sequence number of the file

  • The name and location of the file at the local site

  • Whether the file contains the beginning of a data dictionary build

  • Whether the file contains the end of a data dictionary build

To display the registered redo log files for each capture process: 

  1. Connect to the database as the XStream administrator.

    See Oracle Database Administrator's Guide for information about connecting to a database in SQL*Plus.

  2. Run the following query:

    COLUMN CONSUMER_NAME HEADING 'Capture|Process|Name' FORMAT A15
    COLUMN SOURCE_DATABASE HEADING 'Source|Database' FORMAT A10
    COLUMN SEQUENCE# HEADING 'Sequence|Number' FORMAT 99999
    COLUMN NAME HEADING 'Archived Redo Log|File Name' FORMAT A20
    COLUMN DICTIONARY_BEGIN HEADING 'Dictionary|Build|Begin' FORMAT A10
    COLUMN DICTIONARY_END HEADING 'Dictionary|Build|End' FORMAT A10
    
    SELECT r.CONSUMER_NAME,
           r.SOURCE_DATABASE,
           r.SEQUENCE#, 
           r.NAME, 
           r.DICTIONARY_BEGIN, 
           r.DICTIONARY_END 
      FROM DBA_REGISTERED_ARCHIVED_LOG r, ALL_CAPTURE c
      WHERE r.CONSUMER_NAME = c.CAPTURE_NAME;  
    

Your output looks similar to the following:

Capture                                                  Dictionary Dictionary
Process         Source     Sequence Archived Redo Log    Build      Build
Name            Database     Number File Name            Begin      End
--------------- ---------- -------- -------------------- ---------- ----------
CAP$_XOUT_1     DBS2.EXAMP       15 /orc/dbs/log/arch2_1 NO         NO
                LE.COM              _15_478347508.arc
CAP$_XOUT_1     DBS2.EXAMP       16 /orc/dbs/log/arch2_1 NO         NO
                LE.COM              _16_478347508.arc 
CAP$_XOUT_2     DBS1.EXAMP       45 /remote_logs/arch1_1 YES        YES
                LE.COM              _45_478347335.arc
CAP$_XOUT_2     DBS1.EXAMP       46 /remote_logs/arch1_1 NO         NO
                LE.COM              _46_478347335.arc
CAP$_XOUT_2     DBS1.EXAMP       47 /remote_logs/arch1_1 NO         NO
                LE.COM              _47_478347335.arc

Assume that this query was run at the dbs2.example.com database, and that cap$_xout_1 is a local capture process, and cap$_xout_2 is a downstream capture process. The source database for the cap$_xout_2 downstream capture process is dbs1.example.com. This query shows that there are two registered archived redo log files for cap$_xout_1 and three registered archived redo log files for cap$_xout_2. This query shows the name and location of each of these files in the local file system.

Displaying Redo Log Files That Are Required by Each Capture Process

A capture process needs the redo log file that includes the required checkpoint SCN, and all subsequent redo log files. You can query the REQUIRED_CHECKPOINT_SCN column in the ALL_CAPTURE data dictionary view to determine the required checkpoint SCN for a capture process. Redo log files before the redo log file that contains the required checkpoint SCN are no longer needed by the capture process. These redo log files can be stored offline if they are no longer needed for any other purpose. If you reset the start SCN for a capture process to a lower value in the future, then these redo log files might be needed.

The query displays the following information for each required archived redo log file:

  • The name of a capture process that uses the file

  • The source database of the file

  • The sequence number of the file

  • The name and location of the required redo log file at the local site

To display this information about each required archive redo log file in a database, run the following query:

  1. Connect to the database as the XStream administrator.

    See Oracle Database Administrator's Guide for information about connecting to a database in SQL*Plus.

  2. Run the following query:

    COLUMN CONSUMER_NAME HEADING 'Capture|Process|Name' FORMAT A15
    COLUMN SOURCE_DATABASE HEADING 'Source|Database' FORMAT A10
    COLUMN SEQUENCE# HEADING 'Sequence|Number' FORMAT 99999
    COLUMN NAME HEADING 'Required|Archived Redo Log|File Name' FORMAT A40
    
    SELECT r.CONSUMER_NAME,
           r.SOURCE_DATABASE,
           r.SEQUENCE#, 
           r.NAME 
      FROM DBA_REGISTERED_ARCHIVED_LOG r, ALL_CAPTURE c
      WHERE r.CONSUMER_NAME =  c.CAPTURE_NAME AND
            r.NEXT_SCN      >= c.REQUIRED_CHECKPOINT_SCN;  
    

Your output looks similar to the following:

Capture                             Required
Process         Source     Sequence Archived Redo Log
Name            Database     Number File Name
--------------- ---------- -------- ----------------------------------------
CAP$_XOUT_1     DBS2.EXAMP       16 /orc/dbs/log/arch2_1_16_478347508.arc
                LE.COM
CAP$_XOUT_2     DBS1.EXAMP       47 /remote_logs/arch1_1_47_478347335.arc
                LE.COM

Displaying SCN Values for Each Redo Log File Used by Each Capture Process

You can display information about the SCN values for archived redo log files that are registered for each capture process in a database by running the query in this section. This query displays information the SCN values for these files for both local capture processes and downstream capture processes. This query also identifies redo log files that are no longer needed by any capture process at the local database.

The query displays the following information for each registered archived redo log file:

  • The capture process name of a capture process that uses the file

  • The name and location of the file at the local site

  • The lowest SCN value for the information contained in the redo log file

  • The lowest SCN value for the next redo log file in the sequence

  • Whether the redo log file is purgeable

To display SCN values for each redo log file used by each capture process: 

  1. Connect to the database as the XStream administrator.

    See Oracle Database Administrator's Guide for information about connecting to a database in SQL*Plus.

  2. Run the following query:

    COLUMN CONSUMER_NAME HEADING 'Capture|Process|Name' FORMAT A15
    COLUMN NAME HEADING 'Archived Redo Log|File Name' FORMAT A25
    COLUMN FIRST_SCN HEADING 'First SCN' FORMAT 99999999999
    COLUMN NEXT_SCN HEADING 'Next SCN' FORMAT 99999999999
    COLUMN PURGEABLE HEADING 'Purgeable?' FORMAT A10
     
    SELECT r.CONSUMER_NAME,
           r.NAME, 
           r.FIRST_SCN,
           r.NEXT_SCN,
           r.PURGEABLE 
      FROM DBA_REGISTERED_ARCHIVED_LOG r, ALL_CAPTURE c
      WHERE r.CONSUMER_NAME = c.CAPTURE_NAME;
    

Your output looks similar to the following:

Capture
Process         Archived Redo Log
Name            File Name                    First SCN     Next SCN Purgeable?
--------------- ------------------------- ------------ ------------ ----------
CAP$_XOUT_1     /private1/ARCHIVE_LOGS/1_       509686       549100 YES
                3_502628294.dbf
 
CAP$_XOUT_1     /private1/ARCHIVE_LOGS/1_       549100       587296 YES
                4_502628294.dbf
 
CAP$_XOUT_1     /private1/ARCHIVE_LOGS/1_       587296       623107 NO
                5_502628294.dbf

The redo log files with YES for Purgeable? for all capture processes will never be needed by any capture process at the local database. These redo log files can be removed without affecting any existing capture process at the local database. The redo log files with NO for Purgeable? for one or more capture processes must be retained.

Listing the Parameter Settings for Each Capture Process

Capture process parameters determine how a capture process operates.

To list the parameter settings for each capture process: 

  1. Connect to the database as the XStream administrator.

    See Oracle Database Administrator's Guide for information about connecting to a database in SQL*Plus.

  2. Run the following query:

    COLUMN CAPTURE_NAME HEADING 'Capture|Process|Name' FORMAT A25
    COLUMN PARAMETER HEADING 'Parameter' FORMAT A30
    COLUMN VALUE HEADING 'Value' FORMAT A10
    COLUMN SET_BY_USER HEADING 'Set by|User?' FORMAT A10
     
    SELECT c.CAPTURE_NAME,
           PARAMETER,
           VALUE,
           SET_BY_USER
      FROM ALL_CAPTURE_PARAMETERS c, ALL_XSTREAM_OUTBOUND o
      WHERE c.CAPTURE_NAME=o.CAPTURE_NAME
      ORDER BY PARAMETER;
    

Your output looks similar to the following:

Capture
Process                                                             Set by
Name                      Parameter                      Value      User?
------------------------- ------------------------------ ---------- ----------
CAP$_XOUT_1               CAPTURE_IDKEY_OBJECTS          N          NO
CAP$_XOUT_1               CAPTURE_SEQUENCE_NEXTVAL       N          NO
CAP$_XOUT_1               DISABLE_ON_LIMIT               N          NO
CAP$_XOUT_1               DOWNSTREAM_REAL_TIME_MINE      Y          NO
CAP$_XOUT_1               EXCLUDETAG                                NO
CAP$_XOUT_1               EXCLUDETRANS                              NO
CAP$_XOUT_1               EXCLUDEUSER                               NO
CAP$_XOUT_1               EXCLUDEUSERID                             NO
CAP$_XOUT_1               GETAPPLOPS                     Y          NO
CAP$_XOUT_1               GETREPLICATES                  N          NO
CAP$_XOUT_1               IGNORE_TRANSACTION                        NO
CAP$_XOUT_1               IGNORE_UNSUPPORTED_TABLE       *          NO
CAP$_XOUT_1               INCLUDE_OBJECTS                           NO
CAP$_XOUT_1               INLINE_LOB_OPTIMIZATION        N          NO
CAP$_XOUT_1               MAXIMUM_SCN                    INFINITE   NO
CAP$_XOUT_1               MAX_SGA_SIZE                   INFINITE   NO
CAP$_XOUT_1               MERGE_THRESHOLD                60         NO
CAP$_XOUT_1               MESSAGE_LIMIT                  INFINITE   NO
CAP$_XOUT_1               MESSAGE_TRACKING_FREQUENCY     2000000    NO
CAP$_XOUT_1               PARALLELISM                    0          NO
CAP$_XOUT_1               SKIP_AUTOFILTERED_TABLE_DDL    Y          NO
CAP$_XOUT_1               SPLIT_THRESHOLD                1800       NO
CAP$_XOUT_1               STARTUP_SECONDS                0          NO
CAP$_XOUT_1               TIME_LIMIT                     INFINITE   NO
CAP$_XOUT_1               TRACE_LEVEL                    0          NO
CAP$_XOUT_1               USE_RAC_SERVICE                N          NO
CAP$_XOUT_1               WRITE_ALERT_LOG                Y          NO
CAP$_XOUT_1               XOUT_CLIENT_EXISTS             Y          NO

Note:

If the Set by User? column is NO for a parameter, then the parameter is set to its default value. If the Set by User? column is YES for a parameter, then the parameter was set by a user and might or might not be set to its default value.

Determining the Applied SCN for Each Capture Process

The applied system change number (SCN) for a capture process is the SCN of the most recent logical change record (LCR) dequeued by the relevant outbound servers. All changes below this applied SCN have been processed by all outbound servers that process changes captured by the capture process.

To determine the applied SCN for each capture process: 

  1. Connect to the database as the XStream administrator.

    See Oracle Database Administrator's Guide for information about connecting to a database in SQL*Plus.

  2. Run the following query:

    COLUMN CAPTURE_NAME HEADING 'Capture Process Name' FORMAT A30
    COLUMN APPLIED_SCN HEADING 'Applied SCN' FORMAT 99999999999
    
    SELECT CAPTURE_NAME, APPLIED_SCN FROM ALL_CAPTURE;
    

Your output looks similar to the following:

Capture Process Name            Applied SCN
------------------------------ ------------
CAP$_XOUT_1                          824825

Displaying the Redo Log Scanning Latency for Each Capture Process

You can find the following information about each capture process by running the query in this section:

  • The redo log scanning latency, which specifies the number of seconds between the creation time of the most recent redo log entry scanned by a capture process and the current time. This number might be relatively large immediately after you start a capture process.

  • The seconds since last recorded status, which is the number of seconds since a capture process last recorded its status.

  • The current capture process time, which is the latest time when the capture process recorded its status.

  • The logical change record (LCR) creation time, which is the time when the data manipulation language (DML) or data definition language (DDL) change generated the redo data at the source database for the most recently captured LCR.

The information displayed by this query is valid only for an enabled capture process.

To display the redo log scanning latency for each capture process: 

  1. Connect to the database as the XStream administrator.

    See Oracle Database Administrator's Guide for information about connecting to a database in SQL*Plus.

  2. Run the following query:

    COLUMN CAPTURE_NAME HEADING 'Capture|Process|Name' FORMAT A12
    COLUMN LATENCY_SECONDS HEADING 'Latency|in|Seconds' FORMAT 999999
    COLUMN LAST_STATUS HEADING 'Seconds Since|Last Status' FORMAT 999999
    COLUMN CAPTURE_TIME HEADING 'Current|Process|Time'
    COLUMN CREATE_TIME HEADING 'Message|Creation Time' FORMAT 999999
    
    SELECT CAPTURE_NAME,
           ((SYSDATE - CAPTURE_MESSAGE_CREATE_TIME)*86400) LATENCY_SECONDS,
           ((SYSDATE - CAPTURE_TIME)*86400) LAST_STATUS,
           TO_CHAR(CAPTURE_TIME, 'HH24:MI:SS MM/DD/YY') CAPTURE_TIME,       
           TO_CHAR(CAPTURE_MESSAGE_CREATE_TIME, 'HH24:MI:SS MM/DD/YY') CREATE_TIME
      FROM V$XSTREAM_CAPTURE;
    

Your output looks similar to the following:

Capture      Latency               Current
Process           in Seconds Since Process           Message
Name         Seconds   Last Status Time              Creation Time
------------ ------- ------------- ----------------- -----------------
CAP$_XOUT_1        1             1 10:32:52 02/28/11 10:32:52 02/28/11

The "Latency in Seconds" returned by this query is the difference between the current time (SYSDATE) and the "Message Creation Time." The "Seconds Since Last Status" returned by this query is the difference between the current time (SYSDATE) and the "Current Process Time."

Displaying the Extra Attributes Captured by a Capture Process

You can use the INCLUDE_EXTRA_ATTRIBUTE procedure in the DBMS_CAPTURE_ADM package to instruct a capture process to capture one or more extra attributes and include the extra attributes in logical change records (LCRs).

To display extra attributes captured by a capture process: 

  1. Connect to the database as the XStream administrator.

    See Oracle Database Administrator's Guide for information about connecting to a database in SQL*Plus.

  2. Run the following query:

    COLUMN CAPTURE_NAME HEADING 'Capture Process' FORMAT A20
    COLUMN ATTRIBUTE_NAME HEADING 'Attribute Name' FORMAT A15
    COLUMN INCLUDE HEADING 'Include Attribute in LCRs?' FORMAT A30
    
    SELECT CAPTURE_NAME, ATTRIBUTE_NAME, INCLUDE 
      FROM ALL_CAPTURE_EXTRA_ATTRIBUTES
      ORDER BY CAPTURE_NAME;
    

Your output looks similar to the following:

Capture Process      Attribute Name  Include Attribute in LCRs?
-------------------- --------------- ------------------------------
CAP$_XOUT_1          ROW_ID          NO
CAP$_XOUT_1          SERIAL#         NO
CAP$_XOUT_1          SESSION#        NO
CAP$_XOUT_1          THREAD#         NO
CAP$_XOUT_1          TX_NAME         YES
CAP$_XOUT_1          USERNAME        NO

Based on this output, the capture process named xcapture includes the transaction name (tx_name) in the LCRs that it captures, but this capture process does not include any other extra attributes in the LCRs that it captures.

See Also:

Monitoring XStream Rules

The ALL_XSTREAM_RULES view contains information about the rules used by outbound servers and inbound servers. If an outbound server was created using the CREATE_OUTBOUND procedure in the DBMS_XSTREAM_ADM package, then these views also contain information about the rules used by the capture process that sends changes to the outbound server. However, if an outbound server was created using the ADD_OUTBOUND procedure, then these views do not contain information about the capture process rules. Also, these views do not contain information about the rules used by any propagation in the stream from a capture process to an outbound server.

To display information about the rules used by XStream components: 

  1. Connect to the database as the XStream administrator.

    See Oracle Database Administrator's Guide for information about connecting to a database in SQL*Plus.

  2. Run the following query:

    COLUMN STREAMS_NAME HEADING 'XStream|Component|Name' FORMAT A9
    COLUMN STREAMS_TYPE HEADING 'XStream|Component|Type' FORMAT A9
    COLUMN RULE_NAME HEADING 'Rule|Name' FORMAT A13
    COLUMN RULE_SET_TYPE HEADING 'Rule Set|Type' FORMAT A8
    COLUMN STREAMS_RULE_TYPE HEADING 'Rule|Level' FORMAT A7
    COLUMN SCHEMA_NAME HEADING 'Schema|Name' FORMAT A6
    COLUMN OBJECT_NAME HEADING 'Object|Name' FORMAT A11
    COLUMN RULE_TYPE HEADING 'Rule|Type' FORMAT A4
    
    SELECT STREAMS_NAME, 
           STREAMS_TYPE,
           RULE_NAME,
           RULE_SET_TYPE,
           STREAMS_RULE_TYPE,
           SCHEMA_NAME,
           OBJECT_NAME,
           RULE_TYPE
      FROM ALL_XSTREAM_RULES;
    

Your output looks similar to the following:

XStream   XStream
Component Component Rule          Rule Set Rule    Schema Object      Rule
Name      Type      Name          Type     Level   Name   Name        Type
--------- --------- ------------- -------- ------- ------ ----------- ----
XOUT      APPLY     ORDERS11      POSITIVE TABLE   OE     ORDERS      DML
XOUT      APPLY     ORDERS12      POSITIVE TABLE   OE     ORDERS      DDL
XOUT      APPLY     ORDER_ITEMS14 POSITIVE TABLE   OE     ORDER_ITEMS DML
XOUT      APPLY     ORDER_ITEMS15 POSITIVE TABLE   OE     ORDER_ITEMS DDL
XOUT      APPLY     HR16          POSITIVE SCHEMA  HR                 DML
XOUT      APPLY     HR17          POSITIVE SCHEMA  HR                 DDL

Notice that the STREAMS_TYPE is APPLY even though the rules are in the positive rule set for the outbound server xout. You can determine the purpose of an apply component by querying the PURPOSE column in the ALL_APPLY view.

The ALL_XSTREAM_RULES view contains more information about the rules used in an XStream configuration than what is shown in this example. For example, you can query this view to show information about the rule sets used by XStream components.

To view information about the rules used by all components, including capture processes, propagations, apply processes, outbound servers, and inbound servers, you can query the ALL_XSTREAM_RULES view. See Oracle Streams Concepts and Administration for sample queries that enable you to monitor rules.

Monitoring Declarative Rule-Based Transformations

A declarative rule-based transformations is a rule-based transformation that covers one of a common set of transformation scenarios for row LCRs. Declarative rule-based transformations are run internally without using PL/SQL.

The query in this section displays the following information about each declarative rule-based transformation in a database:

  • The owner of the rule for which a declarative rule-based transformation is specified.

  • The name of the rule for which a declarative rule-based transformation is specified.

  • The type of declarative rule-based transformation specified. The following types are possible: ADD COLUMN, DELETE COLUMN, KEEP COLUMNS, RENAME COLUMN, RENAME SCHEMA, and RENAME TABLE.

  • The precedence of the declarative rule-based transformation. The precedence is the execution order of a transformation in relation to other transformations with the same step number specified for the same rule. For transformations with the same step number, the transformation with the lowest precedence is executed first.

  • The step number of the declarative rule-based transformation. If more than one declarative rule-based transformation is specified for the same rule, then the transformation with the lowest step number is executed first. You can specify the step number for a declarative rule-based transformation when you create the transformation.

You must have DBA role in order to access the DBA_XSTREAM_TRANSFORMATIONS view.

Run the following query to display this information for the declarative rule-based transformations in a database:

  1. Connect to the database as the XStream administrator.

    See Oracle Database Administrator's Guide for information about connecting to a database in SQL*Plus.

  2. Run the following query:

    COLUMN RULE_OWNER HEADING 'Rule Owner' FORMAT A15
    COLUMN RULE_NAME HEADING 'Rule Name' FORMAT A15
    COLUMN DECLARATIVE_TYPE HEADING 'Declarative|Type' FORMAT A15
    COLUMN PRECEDENCE HEADING 'Precedence' FORMAT 99999
    COLUMN STEP_NUMBER HEADING 'Step Number' FORMAT 99999
    
    SELECT RULE_OWNER, 
           RULE_NAME, 
           DECLARATIVE_TYPE,
           PRECEDENCE,
           STEP_NUMBER
      FROM DBA_XSTREAM_TRANSFORMATIONS
      WHERE TRANSFORM_TYPE = 'DECLARATIVE TRANSFORMATION';
    

Your output looks similar to the following:

                                Declarative
Rule Owner      Rule Name       Type            Precedence Step Number
--------------- --------------- --------------- ---------- -----------
XSTRMADMIN      JOBS26          RENAME TABLE             4           0
XSTRMADMIN      EMPLOYEES22     ADD COLUMN               3           0

Based on this output, the ADD COLUMN transformation executes before the RENAME TABLE transformation because the step number is the same (zero) for both transformations and the ADD COLUMN transformation has the lower precedence.

The DBA_XSTREAM_TRANSFORMATIONS view can display more detailed information about each transformation based on the declarative type of the transformation. Include a WHERE clause in the query with the DECLARATIVE_TYPE equal to the type of transformation, such as ADD COLUMN, DELETE COLUMN, and so on.

For example, the previous query listed an ADD COLUMN transformation and a RENAME TABLE transformation. The following sections contain queries that display detailed information about these transformations:

Note:

Precedence and step number pertain only to declarative rule-based transformations. They do not pertain to subset rule transformations or custom rule-based transformations.

Displaying Information About ADD COLUMN Transformations

The query in this section displays detailed information about the ADD COLUMN declarative rule-based transformations in a database.

You use the view DBA_XTREAM_TRANSFORMATIONS to display information about the columns that are added to row LCRs with the declarative rule-based transformation procedure DBMS_XSTREAM_ADM.

To display information about ADD COLUMN transformations: 

  1. Connect to the database as the XStream administrator.

    See Oracle Database Administrator's Guide for information about connecting to a database in SQL*Plus.

  2. Run the following query:

    COLUMN RULE_OWNER HEADING 'Rule|Owner' FORMAT A10
    COLUMN RULE_NAME HEADING 'Rule|Name' FORMAT A11
    COLUMN SCHEMA_NAME HEADING 'Schema|Name' FORMAT A6
    COLUMN TABLE_NAME HEADING 'Table|Name' FORMAT A9
    COLUMN COLUMN_NAME HEADING 'Column|Name' FORMAT A10
    COLUMN COLUMN_VALUE HEADING 'Column|Value' FORMAT A10
    COLUMN COLUMN_TYPE HEADING 'Column|Type' FORMAT A8
    
    SELECT RULE_OWNER,
           RULE_NAME,
           SCHEMA_NAME,
           TABLE_NAME,
           COLUMN_NAME,
           ANYDATA.AccessDate(COLUMN_VALUE) "Value",
           COLUMN_TYPE
      FROM DBA_XSTREAM_TRANSFORMATIONS
      WHERE DECLARATIVE_TYPE = 'ADD COLUMN';
    

Your output looks similar to the following:

Rule       Rule        Schema   Table    Column     Column      Column
Owner      Name        Name     Name     Name       Value       Type
----------  ----------- ------  --------- ---------- ---------- --------
XSTRMADMIN  EMPLOYEES22 HR      EMPLOYEES BIRTH_DATE            SYS.DATE

This output show the following information about the ADD COLUMN declarative rule-based transformation:

  • It is specified on the employees22 rule in the xstrmadmin schema.

  • It adds a column to row LCRs that involve the employees table in the hr schema.

  • The column name of the added column is BIRTH_DATE.

  • The value of the added column is NULL. The COLUMN_VALUE column in the ALL_XSTREAM_TRANSFORMATIONS view is type ANYDATA. In this example, because the column type is DATE, the ANYDATA.AccessDate member function is used to display the value. Use the appropriate member function to display values of other types.

  • The column type of the added column is DATE.

Displaying Information About RENAME TABLE Transformations

The query in this section displays detailed information about the RENAME TABLE declarative rule-based transformations in a database.

You use the view DBA_XSTREAM_TRANSFORMATIONS to display information about declarative rule-based transformations that rename a table in a row logical change record (LCR).

To display information about RENAME TABLE transformations: 

  1. Connect to the database as the XStream administrator.

    See Oracle Database Administrator's Guide for information about connecting to a database in SQL*Plus.

  2. Run the following query:

    COLUMN RULE_OWNER HEADING 'Rule|Owner' FORMAT A10
    COLUMN RULE_NAME HEADING 'Rule|Name' FORMAT A10
    COLUMN FROM_SCHEMA_NAME HEADING 'From|Schema|Name' FORMAT A10
    COLUMN TO_SCHEMA_NAME HEADING 'To|Schema|Name' FORMAT A10
    COLUMN FROM_TABLE_NAME HEADING 'From|Table|Name' FORMAT A15
    COLUMN TO_TABLE_NAME HEADING 'To|Table|Name' FORMAT A15
    
    SELECT RULE_OWNER, 
           RULE_NAME, 
           FROM_SCHEMA_NAME,
           TO_SCHEMA_NAME,
           FROM_TABLE_NAME,
           TO_TABLE_NAME
      FROM DBA_XSTREAM_TRANSFORMATIONS
      WHERE DECLARATIVE_TYPE = 'RENAME TABLE';
    

Your output looks similar to the following:

                      From       To         From            To
Rule       Rule       Schema     Schema     Table           Table
Owner      Name       Name       Name       Name            Name
---------- ---------- ---------- ---------- --------------- ---------------
XSTRMADMIN JOBS26     HR         HR         HR.JOBS         HR.ASSIGNMENTS

This output show the following information about the RENAME TABLE declarative rule-based transformation:

  • It is specified on the jobs26 rule in the xstrmadmin schema.

  • It renames the hr.jobs table in row LCRs to the hr.assignments table.