Acumatica · Cache

Acumatica Cache Attach — The Invalidation Pitfalls

Acumatica cache attach is the most subtle and most abused feature in customisation. A clear explanation of what it does, when to use it, and the pitfalls that catch even senior developers.

John Kihiu7 min read

Cache attach is how Acumatica graph extensions share data with their base graph. It is also how you can silently corrupt the data context if you are not careful. Here is the mental model that makes it predictable.

What cache attach does

When you extend a graph, you can declare a [PXCacheName]-decorated DAC that the base graph "does not know about". By attaching it to the base graph, the extension makes the data visible to the base graph's views, events, and actions.

The three pitfalls

  1. Attaching too aggressively. If your extension attaches a DAC that the base graph already knows, you create duplicate views, doubled event handlers, and memory waste.
  2. Forgetting to invalidate. When you update a cached value outside a graph context, the cache will serve stale data. Call cache.Clear() or cache.ClearQueryCache() deliberately.
  3. Sharing data across graphs. A cache is per-graph-instance. A separate graph will not see your changes.

The "the value didn't update" bug in Acumatica customizations is almost always a cache invalidation bug. Always suspect the cache first.

Going deeper: production-grade patterns

The patterns above cover the basics. In production, the same patterns have to survive three things: scale, edge cases, and the next Acumatica upgrade. Here are the patterns that distinguish a working customisation from a great one — the ones I have applied to every client project in East and Southern Africa, and the ones that make the difference between a customisation the user trusts and a customisation they curse.

Defensive coding for the unexpected

Production is where the assumption dies. Every customisation that "works in test" fails in production the first time a customer name has a special character, an invoice is in a foreign currency, or a record has a null in a field you thought was required. The defensive habit is to explicitly handle the null, the empty, the special character, and the foreign currency in every event handler and every code path. The cost is 20% more code. The payoff is 95% fewer production tickets.

Three patterns I apply everywhere:

C# · DEFENSIVE PATTERN
public class DefensiveExt : PXGraphExtension<BaseGraph>
{
    protected void _(Events.RowSelected<MyDAC> e)
    {
        var row = e.Row;
        if (row == null) return;                          // null-safe
        var ext = row.GetExtension<MyDACExt>();
        if (ext == null) return;                         // null-safe extension
        var value = ext.UsrField ?? "DEFAULT";           // null-coalesce
        var ok = decimal.TryParse(value, out var n);    // try-parse
        if (!ok) { /* handle */ }
    }
}

Performance: the patterns that scale

Five performance patterns I apply on every customisation, in order of impact:

  1. Move heavy logic out of RowSelected. Push validation to RowPersisting, side effects to a graph action triggered by a button. RowSelected fires for every row on every render.
  2. Index the join columns. Every BQL Where<> filter needs an index. Check the execution plan before you ship.
  3. Filter at the GI, not the UI. A GI that returns 5 million rows and filters in the presentation layer will time out. Push filters into the Conditions tab.
  4. Batch the work. Loop with 1,000 calls is slow; loop with 10 calls of 100 records is fast. Batch where you can.
  5. Cache the static. Tax schedules, account lists, and other static reference data can be cached for the lifetime of the app pool. Reduce the database load.

For the full performance playbook, see the performance tuning guide and the SQL Server indexing guide.

Upgrade survival

The customisation that breaks on the next Acumatica upgrade is the one that took a shortcut. The patterns that survive:

C# · USR PREFIX CONVENTION
// Base field — Acumatica owns this
[PXDBString(40)]
public string RefNbr { get; set; }

// Your field — always Usr prefix, never collides
[PXDBString(40)]
[PXUIField(DisplayName = "External Ref")]
public string UsrExternalRef { get; set; }

// Your DAC extension — soft extension, survives table drops
[PXTable(IsOptional = true)]
public class MyDACExt : PXCacheExtension<MyDAC>
{
    #region UsrCustomField
    [PXDBString(60)]
    public string UsrCustomField { get; set; }
    public abstract class usrCustomField :
        PX.Data.BQL.BqlString.Field<usrCustomField> { }
    #endregion
}

Testing: the habit that pays for itself

If you are not testing your customisation with the Acumatica Unit Test Framework, you are running blind. The framework ships with every installation, costs nothing, and pays for itself the first time an upgrade changes a method signature on you. The minimum coverage:

For the full test framework walkthrough, see the unit test framework guide.

Operations: what to do after the customisation is live

A customisation is not "done" when it ships. It is "done" when it has run in production for a quarter without a critical incident. The operational habits that get you there:

For the broader operational patterns, see the monitoring guide and the licence concurrency guide.

The migration off the old customisation

Every customisation is eventually replaced. Plan for that day from the start. The patterns:

For the broader migration patterns, see the data migration guide.

Wrapping up

That is the working approach I use on Acumatica projects. The same patterns show up whether you are in Nairobi, Johannesburg, Kigali, Lusaka or Harare — and they are the things that keep work moving when an upgrade lands at 6 PM on a Friday. If you are stuck on something specific, reach out or keep reading through the rest of the Acumatica blog.

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