[jira] [Created] (DAFFODIL-1877) Slow schema compilation due to unambiguous checks

["Steve Lawrence (JIRA)" <ji...@apache.org>]

Steve Lawrence created DAFFODIL-1877:
----------------------------------------

             Summary: Slow schema compilation due to unambiguous checks
                 Key: DAFFODIL-1877
                 URL: https://issues.apache.org/jira/browse/DAFFODIL-1877
             Project: Daffodil
          Issue Type: Bug
          Components: Front End, Performance
            Reporter: Steve Lawrence
             Fix For: 2.1.0


Commit 02c8324294ed4395c1231c6ea3ec6ae77139ba46 caused ATO schema compilation time to jump from about 10 seconds to over 2 minutes. Large increases were also seen in VMF schema compilation.

Some debugging showed that the cause is likely in the DFDLPathExpressionCompiler. Wrapping the following code the compiles an individual expression in a Timer shows an average of 9000% increase in time to compile.

```scala

val compiler = new DFDLPathExpressionParser[T](qn,
 nodeInfoKind, namespaces, compileInfoWherePropertyWasLocated, isEvaluatedAbove)
 val compiledDPath = compiler.compile(expr)
 compiledDPath

```

So this most likely has something to do with schema compilation. Nothing jumps out at me in the specified commit as being especially egregious to cause such a performance degredation. All the really changed was passing an extra parameter for error accumulation and changing how isReferencedByExpressions is set. I wouldn't expect that to cause such performance changes. Perhaps it is findNamedMatches now allocating a Seq?



--
This message was sent by Atlassian JIRA
(v7.6.3#76005)