When to use PURGE vs APPEND for an international DNC file

When you load an international DNC list into VICIdial, one of the three required fields is the DNC file action. You have two choices: PURGE or APPEND. Choosing the wrong one can either leave stale suppression data in the table or silently drop numbers that should still be suppressed. Understanding what each option does at the database level makes the decision straightforward.

What each action does

PURGE replaces the existing data in the country's DNC suppression table with the contents of the incoming file. Every number that was previously stored for that country is removed, and only the numbers in the new file remain. APPEND does the opposite: it inserts new distinct numbers from the incoming file into the table alongside the records already there. Existing numbers stay in place; only numbers not already present are added.

flowchart LR
  A[Upload DNC file] --> B{File action}
  B -->|PURGE| C[Delete all existing records for country]
  C --> D[Insert all numbers from new file]
  B -->|APPEND| E[Keep all existing records]
  E --> F[Insert only new distinct numbers]
  D --> G[Country DNC table updated]
  F --> G

When PURGE is the right choice

Use PURGE when the new file is a complete, authoritative replacement for the country's DNC data. The most common scenario is a periodic refresh: the regulatory body or your data provider sends an updated full list each month, and that list supersedes everything from the prior period. In that case you want the old table data gone — otherwise numbers that were removed from the official list remain in your Internal DNC table, suppressing leads that are now legally dialable.

PURGE is also the right choice when you discover the existing data is incorrect — for example, if a previous file was loaded with the wrong country code, or the file contained bad data. A PURGE with the correct file starts clean and ensures nothing from the bad load lingers in the table.

When APPEND is the right choice

Use APPEND when the incoming file contains only incremental additions — numbers that should be added to the existing suppression set without disturbing records already there. This happens when your provider sends delta files: additions since the last full export, rather than a complete replacement. It is also useful when you are combining multiple source files for the same country. Each file adds to the table rather than resetting it.

The APPEND operation only inserts distinct numbers, so loading overlapping files does not create duplicate entries in the table. You do not need to pre-deduplicate the incoming file against the existing data before uploading. VICIdial handles that at the database level during the insert.

First load for a country

If no file has ever been loaded for a particular country, the country's DNC table is empty. In that case PURGE and APPEND produce identical results: both load the file's numbers into an empty table. There is no existing data to replace or preserve. You can pick either option on a first load without affecting the outcome. This is worth knowing because it means you do not need to second-guess the choice if you are setting up a country's DNC for the first time.

The compliance risk of choosing wrong

The Campaign DNC scrub that runs when the Lead loader imports records depends entirely on what is in the country table at that moment. A PURGE that inadvertently removes a large portion of the suppression data creates a compliance gap until the next correct file is loaded. Any leads imported during that window may include numbers that should have been blocked. Treating the PURGE vs APPEND decision with care — the same care you would give a destructive database operation — prevents that kind of exposure.

For a full walkthrough of the upload process including setting the country code and file layout, see how to upload and load a country DNC list in bulk. For context on how all the international DNC tools connect, read our VICIdial admin bulk tools guide.

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