Support of current_schema as function (#6886)

Author: vitstn

ydb/library/yql/sql/pg/pg_sql.cpp

@@ -3517,20 +3517,23 @@ class TConverter : public IPGParseEvents {
 
             return L(A("PgConst"), QA(database ? *database : "postgres"), L(A("PgType"), QA("name")));
         }
-        case SVFOP_CURRENT_SCHEMA: {
-            std::optional<TString> searchPath;
-            if (Settings.GUCSettings) {
-                searchPath = Settings.GUCSettings->Get("search_path");
-            }
-
-            return L(A("PgConst"), QA(searchPath ? *searchPath : "public"), L(A("PgType"), QA("name")));
-        }
+        case SVFOP_CURRENT_SCHEMA:
+            return GetCurrentSchema();
         default:
             AddError(TStringBuilder() << "Usupported SQLValueFunction: " << (int)value->op);
             return nullptr;
         }
     }
 
+    TAstNode* GetCurrentSchema() {
+        std::optional<TString> searchPath;
+        if (Settings.GUCSettings) {
+            searchPath = Settings.GUCSettings->Get("search_path");
+        }
+
+        return L(A("PgConst"), QA(searchPath ? *searchPath : "public"), L(A("PgType"), QA("name")));
+    }
+
     TAstNode* ParseBooleanTest(const BooleanTest* value, const TExprSettings& settings) {
         AT_LOCATION(value);
 
@@ -3997,6 +4000,10 @@ class TConverter : public IPGParseEvents {
             return L(A("Null"));
         }
 
+        if (name == "current_schema") {
+            return GetCurrentSchema();
+        }
+
         // for zabbix https://github.com/ydb-platform/ydb/issues/2904
         if (name == "pg_try_advisory_lock" || name == "pg_try_advisory_lock_shared" || name == "pg_advisory_unlock" || name == "pg_try_advisory_xact_lock" || name == "pg_try_advisory_xact_lock_shared"){
             AddWarning(TIssuesIds::PG_COMPAT, name + " function forced to return OK without waiting and without really lock/unlock");

ydb/library/yql/tests/sql/dq_file/part11/canondata/result.json

@@ -2258,9 +2258,9 @@
     ],
     "test.test[pg_catalog-user-default.txt-Debug]": [
         {
-            "checksum": "d5452a3a8b3315f78096106246b0cc4f",
-            "size": 734,
-            "uri": "https://{canondata_backend}/1031349/f9e5528e64f4bcdb4154fd10489bc2c93c9230cf/resource.tar.gz#test.test_pg_catalog-user-default.txt-Debug_/opt.yql_patched"
+            "checksum": "c0c4cb48beaa172880a589e79e2d9cab",
+            "size": 830,
+            "uri": "https://{canondata_backend}/1925821/2762f8f29ee80e9d69a3fae7ac21750c067803da/resource.tar.gz#test.test_pg_catalog-user-default.txt-Debug_/opt.yql_patched"
         }
     ],
     "test.test[pg_catalog-user-default.txt-Plan]": [

ydb/library/yql/tests/sql/hybrid_file/part10/canondata/result.json

@@ -2479,9 +2479,9 @@
     ],
     "test.test[pg_catalog-user-default.txt-Debug]": [
         {
-            "checksum": "ffdea96691e646c2bfa1b8d4e063f06d",
-            "size": 733,
-            "uri": "https://{canondata_backend}/1031349/45aada6c316544e03166fc51527848ab05146f50/resource.tar.gz#test.test_pg_catalog-user-default.txt-Debug_/opt.yql_patched"
+            "checksum": "4af800de2b7698d999d63cbeb508e93b",
+            "size": 829,
+            "uri": "https://{canondata_backend}/937458/8c856e93170e875aa0a26dc4a34de068016e4377/resource.tar.gz#test.test_pg_catalog-user-default.txt-Debug_/opt.yql_patched"
         }
     ],
     "test.test[pg_catalog-user-default.txt-Plan]": [

ydb/library/yql/tests/sql/sql2yql/canondata/result.json

@@ -15051,9 +15051,9 @@
     ],
     "test_sql2yql.test[pg_catalog-user]": [
         {
-            "checksum": "b317c499b3d4e34107e1430e89576b26",
-            "size": 1450,
-            "uri": "https://{canondata_backend}/1925821/85af800a282697ba458d7b0567031a1eadd214a4/resource.tar.gz#test_sql2yql.test_pg_catalog-user_/sql.yql"
+            "checksum": "a7b59168ee545aec600996c65be07ab4",
+            "size": 1626,
+            "uri": "https://{canondata_backend}/1773845/dbc47337ac2531600b4ba49bf1235a6f07ff1422/resource.tar.gz#test_sql2yql.test_pg_catalog-user_/sql.yql"
         }
     ],
     "test_sql2yql.test[pragma-classic_division]": [

ydb/library/yql/tests/sql/suites/pg_catalog/user.sql

@@ -1,5 +1,6 @@
 --!syntax_pg
-select user, current_user, current_role, current_catalog, current_schema;
+select user, current_user, current_role, current_catalog, current_schema, current_schema();
 set search_path to "pg_catalog";
-select user, current_user, current_role, current_catalog, current_schema;
+select user, current_user, current_role, current_catalog, current_schema, current_schema();
+
 

ydb/library/yql/tests/sql/yt_native_file/part11/canondata/result.json

@@ -2188,9 +2188,9 @@
     ],
     "test.test[pg_catalog-user-default.txt-Debug]": [
         {
-            "checksum": "a3ac463405bd37eba6e90620a124fe96",
-            "size": 673,
-            "uri": "https://{canondata_backend}/1031349/e0d85027c4e39b38b460c0dbc0618a662f8a1dc3/resource.tar.gz#test.test_pg_catalog-user-default.txt-Debug_/opt.yql"
+            "checksum": "f3befc2c7ccd151ec1627935713e944f",
+            "size": 768,
+            "uri": "https://{canondata_backend}/1899731/8e3863ca69967a81b91196b65004961a7c52e2a5/resource.tar.gz#test.test_pg_catalog-user-default.txt-Debug_/opt.yql"
         }
     ],
     "test.test[pg_catalog-user-default.txt-Plan]": [
@@ -2202,9 +2202,9 @@
     ],
     "test.test[pg_catalog-user-default.txt-Results]": [
         {
-            "checksum": "231a565780cbd001099daeb95dc7ed4e",
-            "size": 4182,
-            "uri": "https://{canondata_backend}/1900335/b19e3a88f54bb49e1964c45fd96be88e34fd38d0/resource.tar.gz#test.test_pg_catalog-user-default.txt-Results_/results.txt"
+            "checksum": "fdb8e5ac8f1bed8efea16c30e07a0286",
+            "size": 4872,
+            "uri": "https://{canondata_backend}/1899731/8e3863ca69967a81b91196b65004961a7c52e2a5/resource.tar.gz#test.test_pg_catalog-user-default.txt-Results_/results.txt"
         }
     ],
     "test.test[produce-process_with_lambda-default.txt-Debug]": [