Package constants by Noremos · Pull Request #8916 · FirebirdSQL/firebird

Noremos · 2026-02-25T08:05:08Z

Package Constants

This PR adds a new database object - Package Constant (#1036). It is a constant value located in a package header (public visibility) or a package body (private visibility). See README.packages.txt for more information.

SYNTAX

Creation:

CREATE PACKAGE <package_name>
AS
BEGIN
    CONSTANT <constant_name> <type> = <constant_expr>; -- public constant
    -- package routines
END

CREATE PACKAGE BODY <package_name>
AS
BEGIN
    CONSTANT <constant_name> <type> = <constant_expr>; -- private constant
    -- package routines
END

<constant_expr> is an expression that remains unchanged after recompilation.

Package constants can be queried using the expression <package_name>.<consatnt_name> outside the package (<consatnt_name> must be a public constant) and using the expression <consatnt_name> inside the package.
To query a constant, the user/role must have USAGE permission on the package.

Other SQL extensions:

COMMENT ON CONSTANT [<schema>.]<package>.<const_name> IS <text>
GRANT USAGE ON PACKAGE  [<schema>.]<package_name> to [<user|role>] <name> [<grant_option>] [<granted_by>]
REVOKE USAGE ON PACKAGE  [<schema>.]<package_name> FROM <user|role> <name> [<granted_by>]
SHOW CONST[ANTS]  [ [<schema>.]<package_name> ] -- isql only

Usage examples:

set autoterm;
CREATE PACKAGE MY_PACKAGE
AS
BEGIN
    CONSTANT PUBLIC_CONST INTEGER = 10;
    FUNCTION MY_SECRET_PRINT() RETURNS INT;
END;

CREATE PACKAGE BODY MY_PACKAGE
AS
BEGIN
    CONSTANT SECRET_1 INTEGER = 15;
    CONSTANT SECRET_2 INTEGER = 30;

    FUNCTION MY_SECRET_PRINT() RETURNS INT
    AS
    BEGIN
        RETURN SECRET_1 * SECRET_2;
    END
END;
commit;

select MY_PACKAGE.PUBLIC_CONST from rdb$database ;
select MY_PACKAGE.MY_SECRET_PRINT() from rdb$database;

System Constants

As an exmaple, 3 consatnts have been added to the RDB$BLOB_UTIL package

FROM_BEGIN  : INTEGER = 0
FROM_CURRENT : INTEGER = 1
FROM_END : INTEGER = 2

System metadata changes

New system table - RDB$CONSTANTS

Table: SYSTEM.RDB$CONSTANTS
RDB$CONSTANT_NAME               (SYSTEM.RDB$FIELD_NAME) CHAR(63) CHARACTER SET SYSTEM.UTF8 Nullable 
RDB$PACKAGE_NAME                (SYSTEM.RDB$PACKAGE_NAME) CHAR(63) CHARACTER SET SYSTEM.UTF8 Nullable 
RDB$FIELD_SOURCE                (SYSTEM.RDB$FIELD_NAME) CHAR(63) CHARACTER SET SYSTEM.UTF8 Nullable 
RDB$PRIVATE_FLAG                (SYSTEM.RDB$SYSTEM_NULLFLAG) SMALLINT Nullable 
RDB$CONSTANT_BLR                (SYSTEM.RDB$CONSTANT_BLR) BLOB segment 80, subtype BLR Nullable 
RDB$CONSTANT_SOURCE             (SYSTEM.RDB$SOURCE) BLOB segment 80, subtype TEXT CHARACTER SET SYSTEM.UTF8 Nullable 
RDB$SCHEMA_NAME                 (SYSTEM.RDB$SCHEMA_NAME) CHAR(63) CHARACTER SET SYSTEM.UTF8 Nullable 
RDB$DESCRIPTION                 (SYSTEM.RDB$DESCRIPTION) BLOB segment 80, subtype TEXT CHARACTER SET SYSTEM.UTF8 Nullable 
CONSTRAINT RDB$INDEX_98:
  Unique key (RDB$SCHEMA_NAME, RDB$PACKAGE_NAME, RDB$CONSTANT_NAME)

A new field has been added to RDB$PACKAGES - RDB$PACKAGE_ID

New indexes:

Unique key SYSTEM.RDB$CONSTANTS  (RDB$SCHEMA_NAME, RDB$PACKAGE_NAME, RDB$CONSTANT_NAME)
Unique key SYSTEM.RDB$PACKAGES (RDB$PACKAGE_ID)

Implementation

Packages have been added to the metacaching system. Since it relies heavily on identifiers, a new ID field (RDB$PACKAGE_ID) has been added to the RDB$PACKAGES table. Constants are stored as an array in the package metacaching object, with a constant_name-to-array_id mapping.

There are also two important points:

All nodes now have an 'is constant' flag, similar to the 'is deterministic' flag. This is necessary to determine whether an expression can initialize a constant.
In the CreateAlterPackageNode node, a lot of code had to be copied and pasted, and adding constants led to complete chaos. Therefore, I decided to slightly refactor this node. All functionality remains the same; only code duplication was removed.

…rong impure cache usage

…stant routine

…_constants

…onstants

sim1984 · 2026-02-25T13:03:32Z

Are comments supported for constants? I didn't see this in the documentation.
Let me clarify what I mean:

COMMENT ON CONSTANT [<schema>.]<package>.<const_name> IS 'Text'

Comments are simply supported for packaged procedures and functions. It would make sense to do the same for constants (and any package objects, for that matter).

COMMENT ON PROCEDURE [<schema>.]<package>.<proc_name> IS 'Text';
COMMENT ON FUNCTION [<schema>.]<package>.<func_name> IS 'Text';

Noremos · 2026-02-25T13:16:08Z

Are comments supported for constants?

No, I didn't plan to implement comments, but I think it's possible. I will take a look

Raise EDS rollback exception before the connection can be released by deleteTransaction(). Cleanup is still performed by catching the error and rethrow the original exception.

… marker

…multi-level LEFT JOINs. I tried it in 2022 but found regressions. Now I cannot reproduce them locally after the fix, so I'm willing to analyze the complete QA results.

…stream must be re-evaluated after the join

…r delay

…onnect (FirebirdSQL#8992) * fix(udr): Add cleanup of UDR objects from `Engine` on attachment disconnect * Revert "fix(udr): Add cleanup of UDR objects from `Engine` on attachment disconnect" This reverts commit 80581c5. * fix(udr): Add cleanup of UDR objects from Engine on attachment disconnect --------- Co-authored-by: Artyom Ivanov <artyom.ivanov@red-soft.ru>

…onstants

This reverts commit 6aabe94.

This reverts commit 97ce417.

…ants

dyemanov · 2026-05-03T08:09:06Z

@Noremos Please resolve the conflict.
@AlexPeshkoff, do you plan to take one more look before it gets merged?

…onstants

Noremos · 2026-05-03T08:17:39Z

@Noremos Please resolve the conflict

Done

asfernandes · 2026-05-04T12:35:02Z

        GRANT SELECT ON TABLE secret TO PACKAGE pk_secret;
        GRANT EXECUTE ON PACKAGE pk_secret TO ROLE role_secret;

+      To use package constants in a select expression, a USAGE permission is required:


I suppose not only in a "select expression", but in any place outside the package it was defined.

asfernandes · 2026-05-04T12:36:26Z


+void write_constants()
+{
+	Firebird::IRequest* req_handle1 = nullptr;


This file already has using namespace Firebird. Do not qualify things with extra Firebird::.

asfernandes · 2026-05-04T12:37:18Z

+			CONST.RDB$PACKAGE_NAME EQ PKG.RDB$PACKAGE_NAME AND
+			PKG.RDB$SYSTEM_FLAG NE 1
+	{
+		QualifiedMetaString name(CONST.RDB$CONSTANT_NAME);


Why not put the schema and package name here directly?

asfernandes · 2026-05-04T12:40:14Z

+		BURP_verbose(USHORT(isc_gbak_writing_constant), SafeArg() << name.toQuotedString().data());
+		put(tdgbl, att_end);
+	}
+	END_FOR;


Suggested change

END_FOR;

END_FOR

asfernandes · 2026-05-04T12:40:22Z

+	END_FOR;
+	ON_ERROR
+		general_on_error();
+	END_ERROR;


Suggested change

END_ERROR;

END_ERROR

asfernandes · 2026-05-04T13:46:02Z

+		attachment->att_database->deletePool(csb_pool);
+	});
+
+	csb_pool = attachment->att_database->createPool(ALLOC_ARGS0);


Based in old code.

asfernandes · 2026-05-04T13:47:31Z

+ */
+
+
+#ifndef JRD_CONSTANT_H


Wrong marker name.

asfernandes · 2026-05-04T13:50:13Z

+		{"EXP", 1, 1, DEFAULT, setParamsDblDec, makeDblDecResult, evlExp, NULL},
+		{"FIRST_DAY", 2, 2, DEFAULT, setParamsFirstLastDay, makeFirstLastDayResult, evlFirstLastDay, (void*) funFirstDay},
+		{"FLOOR", 1, 1, DEFAULT, setParamsDblDec, makeCeilFloor, evlFloor, NULL},
+		{"GEN_UUID", 0, 0, CONSTANT, NULL, makeUuid, evlGenUuid, NULL},


GEN_UUID is not constant.

asfernandes · 2026-05-04T13:51:10Z

+			const std::initializer_list<UCHAR> aValueBlr = {}
+		)
+			: name(aName),
+			fieldId(aFieldId),


Wrong indentation.

asfernandes · 2026-05-04T13:51:53Z

+
+			EVL_field(0, rpb->rpb_record, f_const_package, &desc2);
+			MOV_get_metaname(tdbb, &desc2, object_name.package);
+


Suggested change

Noremos · 2026-05-04T18:04:06Z

@asfernandes, thanks for the review. I'll resolve the issues tomorrow

Artyom Abakumov added 22 commits February 11, 2026 13:28

Implement package constants

5aa9116

Add "is constant" flag to nodes

251615c

Fix blr parsing, generate unique names for constant FIELD_NAME, fix w…

2d35ecc

…rong impure cache usage

Improve error message for non constant expression

75db5ab

Add missing SCHEMA set to package constants, fix incorrect cached con…

e54c9e6

…stant routine

Add missing resource allocation and transfer for constants

45d62b7

Fix invalid constant and package name in store_dependencies

06411d7

Fix invalid constant drop

3dc1d3d

Fix constant evaluating in BLR Parse

d048560

Fix constants collecting and dtype_dec64 parsing

6231dbc

Fix incorrect ambiguity check

05342aa

Update support for complex dtypes

459354f

Cleanup

3c2c61e

Rollback unneccecery changes

fd208d1

Move all constant related routines to Constant class

8a982ac

Add description for package constants

c42bd55

Cleanup

4a556aa

Delete string in impure

44a7050

Merge remote-tracking branch 'upstream/master' into metacache_package…

c2caa1b

…_constants

Merge remote-tracking branch 'origin/master' into metacache_package_c…

4294bc4

…onstants

Resolve incorrect merge with LTT

3148971

One more cleanup (preparation) before PR

51fc8d7

dyemanov assigned dyemanov and unassigned dyemanov Feb 25, 2026

dyemanov self-requested a review February 25, 2026 08:09

dyemanov assigned Noremos Feb 25, 2026

dyemanov added type: new feature component: engine labels Feb 25, 2026

AlexeyMochalov and others added 19 commits April 27, 2026 10:25

Fix EDS connection use after free

8eea06a

Raise EDS rollback exception before the connection can be released by deleteTransaction(). Cleanup is still performed by catching the error and rethrow the original exception.

fix gbak restore buffer sizing by reserving space for the next record…

c549f4b

… marker

First attempt to FirebirdSQL#8995: Excessive predicate evaluation in …

f1c3e53

…multi-level LEFT JOINs. I tried it in 2022 but found regressions. Now I cannot reproduce them locally after the fix, so I'm willing to analyze the complete QA results.

increment build number

a0ec40b

Fix some cases with outer joins, predicates pushed into the inner sub…

0ab5acd

…stream must be re-evaluated after the join

Completed support of GTT in shared metadata cache

f8e1775

Rolled back my old commit due to caused regressions

4281d2d

Minor enhancement: avoid 2 parallel shutdown threads with short linge…

542045b

…r delay

increment build number

e78ac9a

Warnings

98d54f4

Use constant as pointed by Adriano

415d9c6

Fixed use of Request in Applier

ccd9433

increment build number

61eaae5

Fix build after merge

bcfb106

Add suggested changes

e735ba6

Fix gap in generator IDs

e69448e

Remove not needed cache warmup

10d7356

Merge remote-tracking branch 'origin/master' into metacache_package_c…

3377303

…onstants

dyemanov approved these changes Apr 27, 2026

View reviewed changes

Artyom Abakumov added 5 commits April 27, 2026 17:29

Add RDB$SYSTEM_FLAG to RDB$CONSTANTS

97ce417

Add missing SYSTEM_FLAG set in RDB$CONSTANT STORE

6aabe94

Revert "Add missing SYSTEM_FLAG set in RDB$CONSTANT STORE"

970b39d

This reverts commit 6aabe94.

Revert "Add RDB$SYSTEM_FLAG to RDB$CONSTANTS"

e7b1fd4

This reverts commit 97ce417.

Use RDB$SYSTEM_FLAG in RDB$PACKAGES to determinate user-created const…

5cf5889

…ants

Merge remote-tracking branch 'origin/master' into metacache_package_c…

18092a5

…onstants

asfernandes requested changes May 4, 2026

View reviewed changes


		EVL_field(0, rpb->rpb_record, f_const_package, &desc2);
		MOV_get_metaname(tdbb, &desc2, object_name.package);

		*/


		#ifndef JRD_CONSTANT_H

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