com.continuent.tungsten.replicator.thl
Class CommitSeqnoTable

java.lang.Object
  com.continuent.tungsten.replicator.thl.CommitSeqnoTable

public class CommitSeqnoTable
extends java.lang.Object

Encapsulates definition and management of the trep_commit_seqno table, which is used to ensure consistency between the current contents of the history table and the actual database. Here are the rules for master and slave:

• Master - Master must update trep_commit_seqno whenever an extracted event is stored.
• Slave - Slave must update trep_commit_seqno whenever an event is applied

Version:

1.0

Author:

Robert Hodges

Field Summary

static java.lang.String

TABLE_NAME

Constructor Summary

CommitSeqnoTable(Database database, java.lang.String schema, java.lang.String tableType, boolean syncNativeSlaveRequired)
Creates a new instance valid for life of the provided database connection.

Method Summary

int	count() Returns the count of rows in the trep_commit_seqno table.
void	expandTasks(int channels) Copies the single task 0 row left by a clean offline operation to add rows for each task in multi-channel operation.
void	initializeTable(int channels) Create the trep_commit_seqno table, if necessary, and ensure the number of channels matches the number of channels.
ReplDBMSHeader	lastCommitSeqno(int taskId) Fetches header data for last committed transaction or null if none such can be found.
ReplDBMSHeader	minCommitSeqno() Returns the header for the lowest committed sequence number or null if none such can be found.
void	prepare(int taskId) Prepares the instance for use.
boolean	reduceTasks(Database conn, int channels) Reduces the trep_commit_seqno table to task 0 entry *provided* there is a task 0 row and provide all rows are at the same sequence number.
void	release() Releases the instance.
void	updateLastCommitSeqno(int taskId, ReplDBMSHeader header, long appliedLatency) Updates the last commit seqno value.
void	validate(int channels)

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

TABLE_NAME

public static final java.lang.String TABLE_NAME

See Also:

Constant Field Values

Constructor Detail

CommitSeqnoTable

public CommitSeqnoTable(Database database,
                        java.lang.String schema,
                        java.lang.String tableType,
                        boolean syncNativeSlaveRequired)
                 throws java.sql.SQLException

Creates a new instance valid for life of the provided database connection.

Throws:

java.sql.SQLException

Method Detail

initializeTable

public void initializeTable(int channels)
                     throws java.sql.SQLException,
                            ReplicatorException

Create the trep_commit_seqno table, if necessary, and ensure the number of channels matches the number of channels.

Parameters:

channels - Number of channels in the pipeline

Throws:

java.sql.SQLException

ReplicatorException

prepare

public void prepare(int taskId)
             throws java.sql.SQLException,
                    ReplicatorException

Prepares the instance for use. This must occur before use.

Throws:

ReplicatorException - Thrown if we don't have a row for this entry

java.sql.SQLException

release

public void release()

Releases the instance. This must occur after last use.

lastCommitSeqno

public ReplDBMSHeader lastCommitSeqno(int taskId)
                               throws java.sql.SQLException

Fetches header data for last committed transaction or null if none such can be found.

Throws:

java.sql.SQLException

minCommitSeqno

public ReplDBMSHeader minCommitSeqno()
                              throws java.sql.SQLException

Returns the header for the lowest committed sequence number or null if none such can be found.

Throws:

java.sql.SQLException

expandTasks

public void expandTasks(int channels)
                 throws java.sql.SQLException,
                        ReplicatorException

Copies the single task 0 row left by a clean offline operation to add rows for each task in multi-channel operation. This fails if task 0 does not exist.

Throws:

ReplicatorException - Thrown if the task ID 0 does not exist

java.sql.SQLException

reduceTasks

public boolean reduceTasks(Database conn,
                           int channels)
                    throws java.sql.SQLException

Reduces the trep_commit_seqno table to task 0 entry *provided* there is a task 0 row and provide all rows are at the same sequence number. This operation allows the table to convert to a different number of apply threads.

Throws:

java.sql.SQLException

updateLastCommitSeqno

public void updateLastCommitSeqno(int taskId,
                                  ReplDBMSHeader header,
                                  long appliedLatency)
                           throws java.sql.SQLException

Updates the last commit seqno value.

Throws:

java.sql.SQLException

count

public int count()
          throws java.sql.SQLException

Returns the count of rows in the trep_commit_seqno table.

Throws:

java.sql.SQLException

validate

public void validate(int channels)
              throws java.sql.SQLException,
                     ReplicatorException

Throws:

java.sql.SQLException

ReplicatorException