Reset Process

The reset command sets the position from which a process continues the next time it is run. For an Apply Process it is the LSN of a transaction in the trail files of its Capture Process, which the Apply Process then applies or skips. For a Capture Process it is the LSN (SQL Server) or the SCN (Oracle) in the Source Database from which the changes are captured, or the current one. The process has to be stopped.

When to use it

• An Apply Process cannot apply a transaction and you have decided to skip it. The message of the process names the LSN of the transaction: reset with that LSN and skip=1, then run the process. Look at what the transaction contains first (see Report Process).
• An Apply Process has to apply transactions again, for example after you have repaired the Target Database. Reset with the LSN of the first transaction to apply and skip=0.
• A Capture Process has to leave out the changes made while it was stopped (lsn=now), or has to start from a position that you know.

Be careful: the transactions between the old and the new position are applied again (Apply), or are not captured at all when the position is moved forward (Capture). A transaction that is applied again can fail with a duplicate key error. After a Capture Process has skipped changes the Target Database does not have them: compare the data and repair it (see Data Comparison) or load the tables again.

With skip=1 the Apply Process leaves out the whole transaction with the LSN: all the rows that it changed in all the tables, not only the row or the statement that failed. A transaction can hold thousands of rows, so much more data than the failed row can be missing in the Target Database. Look at the transaction before you leave it out: the command report with the LSN at both ends lists its tables, with the numbers of inserts, updates and deletes (see Report Process). Use skip=1 when there is no other way, and compare and repair the tables that the report listed (see Data Comparison). When the transaction fails because a column or a table is missing in the Target Database, a rule of the Apply Process that leaves it out is a smaller step: the transaction is then applied without it (see Apply and Target Databases).

Command line (repcli)

The command returns at once. The process shows RESET (Completed) when it is done; it stays stopped, run it to continue from the new position (see Run any Capture or Apply Processes). The command is refused for a process that is running: stop it first (see Stop any Capture or Apply Processes).

Make an Apply Process start after the transaction with the last applied LSN:

Make an Apply Process start with a transaction:

The status of the Apply Process after the reset:

Make a Capture Process continue from the current position of the Source Database:

The Capture Process does not look for the current position when the command is given: it starts from the position that the Source Database has when the process is run. The changes made between the reset and the run are not captured. After the process has been run, the line “Total since” of status shows for a SQL Server Source Database the position 0x00000000000000000000, until the process is stopped and run again (for an Oracle Source Database it shows the position where the process started):

The messages when the command is refused. repcli prints them at once:

The Apply Process looks for the LSN after the command has been accepted, so the answer of the command is In Process also when the LSN is not in the trail files. The result is in the status of the process: it shows RESET (Failed) with a message that names the first LSN that is available. Reset the process again with an LSN from the trail files:

REST API

• Endpoint: https://repstance_url/reset/process
• Method: POST
• Header: Content-Type: application/json and X-Token: token

The body of the request. The pairs are in this order; the pair skip is only for an Apply Process:

The body of the answer is one object (not an array):

Web UI

Stop the process first (see Stop/Run Replication Processes): a running process cannot be reset. Then click “More” on the card of the process:

The window of the process opens. Click “Reset” at the bottom of the window:

The window “Reset Apply Process” opens. Enter the LSN. Tick “Skip” to start after the transaction with this LSN, leave it unticked to start with it. Click “Reset”:

The window “Reset Capture Process” has no “Skip”. Enter an LSN, or now to continue from the current position of the Source Database, and click “Reset”:

“Show JSON” shows the request that the button sends, the one that is described under REST API above, and “Copy” copies it. The LSN is required: the Web UI only checks that the field is filled in.

When the server accepts the reset, the process stays stopped at the new position. The window shows it as Stopped; repcli status shows RESET (Completed). Click “Run Process” to continue from the new position:

If the Apply Process does not find the LSN in the trail files, the window shows the process as Failed with the message and the first LSN that is available. Click “Reset” again and enter an LSN from the trail files:

The Web UI does not show a message when the server refuses a reset, for example because the process is running or the LSN is not valid: the window closes and nothing changes. Check the state of the process in the window, or send the command with repcli to see the message.