Changes to address issue 148

src/hooks/executor_start.c

@@ -7,6 +7,8 @@
 #include <nodes/nodes.h>
 #include <nodes/pg_list.h>
 #include <nodes/plannodes.h>
+#include <utils/builtins.h>
+#include <catalog/namespace.h>
 
 #include "../hnsw/utils.h"
 #include "plan_tree_walker.h"
@@ -17,25 +19,44 @@ ExecutorStart_hook_type original_ExecutorStart_hook = NULL;
 typedef struct
 {
     List *oidList;
+    List *distanceFunctionOidList;
+    Oid   defaultDistanceFunction;
     bool  isIndexScan;
+    bool  isSequentialScan;
 } OperatorUsedCorrectlyContext;
 
 static bool operator_used_incorrectly_walker(Node *node, void *context)
 {
     OperatorUsedCorrectlyContext *context_typed = (OperatorUsedCorrectlyContext *)context;
+
     if(node == NULL) return false;
     if(IsA(node, IndexScan)) {
         context_typed->isIndexScan = true;
         bool status = plan_tree_walker((Plan *)node, operator_used_incorrectly_walker, context);
         context_typed->isIndexScan = false;
         return status;
     }
+    if (IsA(node, SeqScan)) {
+        context_typed->isSequentialScan = true;
+        bool status = plan_tree_walker((Plan *)node, operator_used_incorrectly_walker, context);
+        context_typed->isSequentialScan = false;
+        return status;       
+    }
+
     if(IsA(node, OpExpr)) {
         OpExpr *opExpr = (OpExpr *)node;
-        if(list_member_oid(context_typed->oidList, opExpr->opno) && !context_typed->isIndexScan) {
+        if(list_member_oid(context_typed->distanceFunctionOidList, opExpr->opno)) {
+            context_typed->defaultDistanceFunction = opExpr->opfuncid;
+        }
+        if(list_member_oid(context_typed->oidList, opExpr->opno) && !context_typed->isIndexScan && !context_typed->isSequentialScan) {
             return true;
         }
+        if(list_member_oid(context_typed->oidList, opExpr->opno) && context_typed->isSequentialScan) {
+            elog(WARNING, "A sequential scan is being used. This might be because queried column doesn't have an index, or the distance function of the column is a different one.");
+            opExpr->opfuncid = context_typed->defaultDistanceFunction;
+        }
     }
+
     if(IsA(node, List)) {
         List     *list = (List *)node;
         ListCell *lc;
@@ -53,11 +74,19 @@ static bool operator_used_incorrectly_walker(Node *node, void *context)
     return false;
 }
 
-static void validate_operator_usage(Plan *plan, List *oidList)
+static void validate_operator_usage(Plan *plan, List *oidList, void *distanceFunctionOidList)
 {
     OperatorUsedCorrectlyContext context;
     context.oidList = oidList;
+    context.distanceFunctionOidList = distanceFunctionOidList;
+    FuncCandidateList funcList1 = FuncnameGetCandidates(list_make1(makeString("l2sq_dist")), -1, NIL, false, false, false, true);
+    if (funcList1 != NULL) {
+        context.defaultDistanceFunction = funcList1->oid;
+    } else {
+        elog(WARNING, "Default distance function was not found.");
+    }
     context.isIndexScan = false;
+    context.isSequentialScan = false;
     if(operator_used_incorrectly_walker((Node *)plan, (void *)&context)) {
         elog(ERROR, "Operator <-> has no standalone meaning and is reserved for use in vector index lookups only");
     }
@@ -70,16 +99,18 @@ void ExecutorStart_hook_with_operator_check(QueryDesc *queryDesc, int eflags)
     }
 
     List *oidList = ldb_get_operator_oids();
+    List *distanceFunctionOidList = ldb_get_distance_function_oids();
     if(oidList != NULL) {
         // oidList will be NULL if LanternDB extension is not fully initialized
         // e.g. in statements executed as a result of CREATE EXTENSION ... statement
-        validate_operator_usage(queryDesc->plannedstmt->planTree, oidList);
+        validate_operator_usage(queryDesc->plannedstmt->planTree, oidList, distanceFunctionOidList);
         ListCell *lc;
         foreach(lc, queryDesc->plannedstmt->subplans) {
             Plan *subplan = (Plan *)lfirst(lc);
-            validate_operator_usage(subplan, oidList);
+            validate_operator_usage(subplan, oidList, distanceFunctionOidList);
         }
         list_free(oidList);
+        list_free(distanceFunctionOidList);
     }
 
     standard_ExecutorStart(queryDesc, eflags);

src/hooks/utils.c

@@ -4,6 +4,10 @@
 #include <nodes/makefuncs.h>
 #include <nodes/pg_list.h>
 #include <parser/parse_oper.h>
+#include <utils/builtins.h>
+#include <catalog/namespace.h>
+
+
 
 List *ldb_get_operator_oids()
 {
@@ -23,5 +27,44 @@ List *ldb_get_operator_oids()
 
     list_free(nameList);
 
+    return oidList;
+}
+
+List *ldb_get_distance_function_oids()
+{
+    List *oidList = NIL;
+
+    Oid l2sq_dist_oid = InvalidOid;
+    Oid cos_dist_oid = InvalidOid;
+    Oid hamming_dist_oid = InvalidOid;
+    FuncCandidateList funcList1 = FuncnameGetCandidates(list_make1(makeString("l2sq_dist")), -1, NIL, false, false, false, true);
+    if (funcList1 != NULL) {
+        l2sq_dist_oid = funcList1->oid;
+    } else {
+        elog(WARNING, "l2sq_dist was not found.");
+    }
+    FuncCandidateList funcList2 = FuncnameGetCandidates(list_make1(makeString("cos_dist")), -1, NIL, false, false, false, true);
+    if (funcList2 != NULL) {
+        cos_dist_oid = funcList2->oid;
+    } else {
+        elog(WARNING, "cos_dist was not found.");
+    }
+    FuncCandidateList funcList3 = FuncnameGetCandidates(list_make1(makeString("hamming_dist")), -1, NIL, false, false, false, true);
+    if (funcList2 != NULL) {
+        hamming_dist_oid = funcList3->oid;
+    } else {
+        elog(WARNING, "hamming_dist was not found.");
+    }
+
+    if(OidIsValid(l2sq_dist_oid)) {
+        oidList = lappend_oid(oidList, l2sq_dist_oid);
+    }
+    if(OidIsValid(cos_dist_oid)) {
+        oidList = lappend_oid(oidList, cos_dist_oid);
+    }
+    if(OidIsValid(hamming_dist_oid)) {
+        oidList = lappend_oid(oidList, hamming_dist_oid);
+    }
+
     return oidList;
 }

src/hooks/utils.h

@@ -6,5 +6,6 @@
 #include <nodes/pg_list.h>
 
 List *ldb_get_operator_oids();
+List *ldb_get_distance_function_oids();
 
 #endif  // LDB_HOOKS_UTILS_H