PostgreSQL Hacker Helper

This is a Visual Studio Code extension to assist PostgreSQL source code developers. It allows to investigate Node * variables to obtain it's real type based on NodeTag and provide some other utilities.

Features

More info you can find in documentation for pg variables view.

Investigate real type of Node *

While debugging you can observe variables of Node * type with it's real type. They appear in separate action view.

It behaves like Debug->Variables view, but no colorization (limitations of VS Code Extension framework) and automatically detects real type of Node * variables.

Also, there are intrinsics for some types:

• List elements are displayed according their types

• Support for special members like PlannerInfo->simple_rel_array - array is
  displayed using it's length

Currently, there are 36 registered special members, but you can add your own using pgsql_hacker_helper.json configuration file.

• Bitmapset elements are displayed:
  • $elements$ - elements of set (array of integers)
  • $length$ - number of entries in set

Dump Node * state to log

In PostgreSQL there is pprint(Node *) which dumps passed Node variable to stdout with pretty printing it. Using 'Dump Node to log' option in variable context menu you also will be able to do so.

Customization

pgsql_hacker_helper.json

This is a configuration file for extension. It stored inside .vscode directory in your repository - .vscode/pgsql_hacker_helper.json. You can use config file to extend built-in capabilities if there is no support for something yet.

Example json:

{
    "version": 2,
    "specialMembers": {
        "array": [
            {
                "typeName": "PlannerInfo",
                "memberName": "simple_rel_array",
                "lengthExpression": "simple_rel_array_size"
            },
            {
                "typeName": "RelOptInfo",
                "memberName": "partexprs",
                "lengthExpression": "part_scheme->partnatts"
            },
            {
                "typeName": "GatherMergeState",
                "memberName": "gm_slots",
                "lengthExpression": "nreaders + 1"
            }
        ]
    },
    "aliases": [
        {
            "alias": "PlannerRef",
            "type": "PlannerInfo *"
        }
    ]
}

In example 3 array special members - arrays will be shown with specified length, not just pointers to arrays start. Also, PlannerRef - typedef for PlannerInfo *.

For more info check configuration file documentation.

Extension Settings

There are 2 settings:

• Log level - set minimum level of log messages in Output channel.
  By default - INFO
• Files with NodeTag files - list of paths points to files that contain NodeTags.
  By default - src/include/nodes/nodes.h, src/include/nodes/nodetags.h

Compatibility

Extension tries to be compatible with multiple versions of both VS Code and PostgreSQL.

Minimal supported version of:

• VS Code - 1.30
• PostgreSQL - 8.0

It is tested manually and not all use cases might be covered. If you found bug specific to some version please create issue.

Also, extension will target latest VS Code version and try to use the full functionality of new versions. So, use latest VS Code versions to get new features earlier.

Known Issues

Known issues:

• Only tested on gdb debugger, UB for other debuggers (i.e. lldb)
• If in pointer variable was garbage, extension will not detect it and expand
  this variable (may be garbage)
• To get NodeTags extension reads all available NodeTag files (from settings),
  but these files may be not created (./configure or make not run). I assume by
  time of debugging start files will be created, so extension catch them and
  process.
• Tested only with ms-vscode.cpptools
  extension

Release Notes

1.2.1

Add check for breakpoint in bms_first_member to avoid infinite loop.

Add support for MemoryContext Node.

1.2.0

Expand range of supported versions both for PostgreSQL (from 8.0) and VS Code (from 1.30).

Add support for Bitmapset for versions below 16.

Add support for List with Linked List implementation.

Fix log level updated only after extension or VS Code reload.

Fix invalid Node cast in some cases when declared type has struct keyword.

1.1.2

Fix invalid List behaviour with different declared type - members shown for declared type, not List members.

Add 137 new array special members.

Optimize extension activation performance.

Treat Plan struct as Node variable.

1.1.1

Fix Bitmapset elements not shown for postgres version below 17

1.1.0

Add support for Bitmapset and Relids - show elements of set.

Add custom user type aliases for Node types in configuration

Update config file layout. Current version - 2.

Hide postgres variables view when not in debug mode.

1.0.0

Remove EPQState from array special members

Add T_XidList support

0.2.0

Add more special members.

Separate json configuration file to add your own special members.

Specifying real NodeTag in variable name if it differs from declared type. Shows in square brackets.

Setup logging infrastructure. Availability to change minimum log level.

Command and button to force refresh Pg variables view.

Setting to add custom files with NodeTags.

0.1.1

Only valid pointers are expanded in Pg variables view

0.1.0

Displaying of Node * variables in separate view in Debug view container.

Call pprint(Node *) on selected variable in Variables view.

Contributing

Go to Issues if you want to say something: bugs, features, etc...