From b23413733232926594299c974f6be0dd84ef3c60 Mon Sep 17 00:00:00 2001
From: Nikolay Shumkov <shumkovnd@ydb.tech>
Date: Tue, 16 Apr 2024 12:44:03 +0300
Subject: [PATCH] Support drop sequence in pg parser (#3733)

---
 ydb/library/yql/sql/pg/pg_sql.cpp    | 43 ++++++++++++++++++++++++++++
 ydb/library/yql/sql/pg/pg_sql_ut.cpp | 14 +++++++++
 2 files changed, 57 insertions(+)

diff --git a/ydb/library/yql/sql/pg/pg_sql.cpp b/ydb/library/yql/sql/pg/pg_sql.cpp
index 782c2e2205b3..9d4e998ad7c7 100644
--- a/ydb/library/yql/sql/pg/pg_sql.cpp
+++ b/ydb/library/yql/sql/pg/pg_sql.cpp
@@ -2091,6 +2091,9 @@ class TConverter : public IPGParseEvents {
             case OBJECT_INDEX: {
                 return ParseDropIndexStmt(value, nameListNodes);
             }
+            case OBJECT_SEQUENCE: {
+                return ParseDropSequenceStmt(value, nameListNodes);
+            }
             default: {
                 AddError("Not supported object type for DROP");
                 return nullptr;
@@ -2207,6 +2210,46 @@ class TConverter : public IPGParseEvents {
         return State.Statements.back();
     }
 
+    TAstNode* ParseDropSequenceStmt(const DropStmt* value, const TVector<const List*>& names) {
+        if (value->behavior == DROP_CASCADE) {
+            AddError("CASCADE is not implemented");
+            return nullptr;
+        }
+
+        if (names.size() != 1) {
+            AddError("DROP SEQUENCE requires exactly one sequence");
+            return nullptr;
+        }
+
+        for (const auto& nameList : names) {
+            const auto [clusterName, indexName] = getSchemaAndObjectName(nameList);
+            const auto [sink, key] = ParseQualifiedPgObjectName(
+                /* catalogName */ "",
+                clusterName,
+                indexName,
+                "pgSequence"
+            );
+
+            TString mode = (value->missing_ok) ? "drop_if_exists" : "drop";
+            State.Statements.push_back(L(
+                A("let"),
+                A("world"),
+                L(
+                    A("Write!"),
+                    A("world"),
+                    sink,
+                    key,
+                    L(A("Void")),
+                    QL(
+                        QL(QA("mode"), QA(mode))
+                    )
+                )
+            ));
+        }
+
+        return State.Statements.back();
+    }
+
     [[nodiscard]]
     TAstNode* ParseVariableSetStmt(const VariableSetStmt* value, bool isSetConfig = false) {
         if (value->kind != VAR_SET_VALUE) {
diff --git a/ydb/library/yql/sql/pg/pg_sql_ut.cpp b/ydb/library/yql/sql/pg/pg_sql_ut.cpp
index 0b9f30529d33..f4e1e33eb51e 100644
--- a/ydb/library/yql/sql/pg/pg_sql_ut.cpp
+++ b/ydb/library/yql/sql/pg/pg_sql_ut.cpp
@@ -282,6 +282,20 @@ Y_UNIT_TEST_SUITE(PgSqlParsingOnly) {
         UNIT_ASSERT_STRINGS_EQUAL(res.Root->ToString(), expectedAst.Root->ToString());
     }
 
+    Y_UNIT_TEST(DropSequenceStmt) {
+        auto res = PgSqlToYql("DROP SEQUENCE IF EXISTS seq;");
+        UNIT_ASSERT_C(res.Root, res.Issues.ToString());
+        TString program = R"(
+            (
+                (let world (Configure! world (DataSource 'config) 'OrderedColumns)) (let world (Write! world (DataSink '"kikimr" '"") (Key '('pgObject (String '"seq") (String 'pgSequence))) (Void) '('('mode 'drop_if_exists))))
+                (let world (CommitAll! world))
+                (return world)
+            )
+        )";
+        const auto expectedAst = NYql::ParseAst(program);
+        UNIT_ASSERT_STRINGS_EQUAL(res.Root->ToString(), expectedAst.Root->ToString());
+    }
+
     Y_UNIT_TEST(VariableShowStmt) {
         auto res = PgSqlToYql("Show server_version_num");
         UNIT_ASSERT(res.Root);