Added new pseudo-extension point, which was why Doltgres was not finding indexes for certain queries

Author: zachmu

sql/analyzer/analyzer.go

@@ -36,6 +36,7 @@ import (
 
 const debugAnalyzerKey = "DEBUG_ANALYZER"
 const verboseAnalyzerKey = "VERBOSE_ANALYZER"
+const traceAnalyzerKey = "TRACE_ANALYZER"
 
 const maxAnalysisIterations = 8
 
@@ -215,6 +216,7 @@ func (s simpleLogFormatter) Format(entry *logrus.Entry) ([]byte, error) {
 func (ab *Builder) Build() *Analyzer {
 	_, debug := os.LookupEnv(debugAnalyzerKey)
 	_, verbose := os.LookupEnv(verboseAnalyzerKey)
+	_, trace := os.LookupEnv(traceAnalyzerKey)
 	var batches = []*Batch{
 		{
 			Desc:       "pre-analyzer",
@@ -266,6 +268,7 @@ func (ab *Builder) Build() *Analyzer {
 	return &Analyzer{
 		Debug:           debug || ab.debug,
 		Verbose:         verbose,
+		Trace:           trace,
 		contextStack:    make([]string, 0),
 		Batches:         batches,
 		Catalog:         NewCatalog(ab.provider),

sql/memo/join_order_builder.go

@@ -26,6 +26,10 @@ import (
 	"github.com/dolthub/go-mysql-server/sql/plan"
 )
 
+// SplitConjunction is a pseudo-extension point of expression.SplitConjunction, used to alter the logic
+// for different integrators.
+var SplitConjunction func(expr sql.Expression) []sql.Expression = expression.SplitConjunction
+
 // joinOrderBuilder enumerates valid plans for a join tree.  We build the join
 // tree bottom up, first joining single nodes with join condition "edges", then
 // single nodes to hypernodes (1+n), and finally hyper nodes to
@@ -510,7 +514,7 @@ func (j *joinOrderBuilder) buildJoinOp(n *plan.JoinNode) *ExprGroup {
 		rightEdges:    rightE,
 	}
 
-	filters := expression.SplitConjunction(n.JoinCond())
+	filters := SplitConjunction(n.JoinCond())
 	j.m.Tracer.Log("Join filters: %v", filters)
 	union := leftV.union(rightV)
 	group, ok := j.plans[union]
@@ -538,7 +542,7 @@ func (j *joinOrderBuilder) buildFilter(child sql.Node, e sql.Expression) (vertex
 	// memoize child
 	childV, childE, childGrp := j.populateSubgraph(child)
 
-	filterGrp := j.m.MemoizeFilter(nil, childGrp, expression.SplitConjunction(e))
+	filterGrp := j.m.MemoizeFilter(nil, childGrp, SplitConjunction(e))
 
 	// filter will absorb child relation for join reordering
 	j.plans[childV] = filterGrp