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Tantor SE 16.8 Documentation

EN RU

Table of contents:

  • Preface
    • 1.  What Is Tantor SE?
    • 2. A Brief History of PostgreSQL
    • 3. What are the differences between Tantor SE 16 and PostgreSQL 16
    • 4. Conventions
    • 5. Bug Reporting Guidelines
  • Part I. Tutorial
    • Chapter 1. Synopsis
    • Chapter 2. The SQL Language
    • Chapter 3. Advanced Features
  • Part II. The SQL Language
    • Chapter 4. SQL Syntax
    • Chapter 5. Data Definition
    • Chapter 6. Data Manipulation
    • Chapter 7. Queries
    • Chapter 8. Data Types
    • Chapter 9. Functions and Operators
    • Chapter 10. Type Conversion
    • Chapter 11. Indexes
    • Chapter 12. Full Text Search
    • Chapter 13. Concurrency Control
    • Chapter 14. Performance Tips
    • Chapter 15. Parallel Query
    • Chapter 16. Autonomous Transactions
  • Part III. Server Administration
    • Chapter 17. Installation from Binaries
    • Chapter 18. Server Setup and Operation
    • Chapter 19. Server Configuration
    • Chapter 20. Client Authentication
    • Chapter 21. Database Roles
    • Chapter 22. Managing Databases
    • Chapter 23. Localization
    • Chapter 24. Routine Database Maintenance Tasks
    • Chapter 25. Backup and Restore
    • Chapter 26. High Availability, Load Balancing, and Replication
    • Chapter 27. Monitoring Database Activity
    • Chapter 28. Monitoring Disk Usage
    • Chapter 29. Reliability and the Write-Ahead Log
    • Chapter 30. Logical Replication
    • Chapter 31. Just-in-Time Compilation (JIT)
  • Part IV. Client Interfaces
    • Chapter 32. libpq — C Library
    • Chapter 33. Large Objects
    • Chapter 34. ECPG — Embedded SQL in C
    • Chapter 35. The Information Schema
  • Part V. Server Programming
    • Chapter 36. Extending SQL
    • Chapter 37. Triggers
    • Chapter 38. Event Triggers
    • Chapter 39. The Rule System
    • Chapter 40. Procedural Languages
    • Chapter 41. PL/pgSQL — SQL Procedural Language
    • Chapter 42. PL/Tcl — Tcl Procedural Language
    • Chapter 43. PL/Perl — Perl Procedural Language
    • Chapter 44. PL/Python — Python Procedural Language
    • Chapter 45. Server Programming Interface
    • Chapter 46. Background Worker Processes
    • Chapter 47. Logical Decoding
    • Chapter 48. Replication Progress Tracking
    • Chapter 49. Archive Modules
  • Part VI. Reference
    • SQL Commands
    • PostgreSQL Client Applications
    • PostgreSQL Server Applications
  • Part VII. Internals
    • Chapter 50. Overview of PostgreSQL Internals
    • Chapter 51. System Catalogs
    • Chapter 52. System Views
    • Chapter 53. Frontend/Backend Protocol
    • Chapter 54. PostgreSQL Coding Conventions
    • Chapter 55. Native Language Support
    • Chapter 56. Writing a Procedural Language Handler
    • Chapter 57. Writing a Foreign Data Wrapper
    • Chapter 58. Writing a Table Sampling Method
    • Chapter 59. Writing a Custom Scan Provider
    • Chapter 60. Genetic Query Optimizer
    • Chapter 61. Table Access Method Interface Definition
    • Chapter 62. Index Access Method Interface Definition
    • Chapter 63. Generic WAL Records
    • Chapter 64. Custom WAL Resource Managers
    • Chapter 65. B-Tree Indexes
    • Chapter 66. GiST Indexes
    • Chapter 67. SP-GiST Indexes
    • Chapter 68. GIN Indexes
    • Chapter 69. BRIN Indexes
    • Chapter 70. Hash Indexes
    • Chapter 71. Database Physical Storage
    • Chapter 72. Transaction Processing
    • Chapter 73. System Catalog Declarations and Initial Contents
    • Chapter 74. How the Planner Uses Statistics
    • Chapter 75. Backup Manifest Format
  • Part VIII. Appendixes
    • Appendix A. Tantor SE Error Codes
    • Appendix B. Date/Time Support
    • Appendix C. SQL Key Words
    • Appendix D. SQL Conformance
    • Appendix E. Release Notes
    • Appendix F. Additional Supplied Modules and Extensions
    • Appendix G. Additional Supplied Programs
    • Appendix H. Additional External Modules
    • Appendix I. External Projects
    • Appendix J. Tantor SE Limits
    • Appendix K. Acronyms
    • Appendix L. Glossary
    • Appendix M. Color Support
    • Appendix N. Obsolete or Renamed Features
  • Bibliography
  • Index

dblink_connect_u

dblink_connect_u#

dblink_connect_u
dblink_connect_u
Prev UpF.14. dblink — connect to other PostgreSQL databasesHome Next

dblink_connect_u

dblink_connect_u — opens a persistent connection to a remote database, insecurely

Synopsis

dblink_connect_u(text connstr) returns text
dblink_connect_u(text connname, text connstr) returns text

Description

dblink_connect_u() is identical to dblink_connect(), except that it will allow non-superusers to connect using any authentication method.

If the remote server selects an authentication method that does not involve a password, then impersonation and subsequent escalation of privileges can occur, because the session will appear to have originated from the user as which the local Tantor SE server runs. Also, even if the remote server does demand a password, it is possible for the password to be supplied from the server environment, such as a ~/.pgpass file belonging to the server's user. This opens not only a risk of impersonation, but the possibility of exposing a password to an untrustworthy remote server. Therefore, dblink_connect_u() is initially installed with all privileges revoked from PUBLIC, making it un-callable except by superusers. In some situations it may be appropriate to grant EXECUTE permission for dblink_connect_u() to specific users who are considered trustworthy, but this should be done with care. It is also recommended that any ~/.pgpass file belonging to the server's user not contain any records specifying a wildcard host name.

For further details see dblink_connect().


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16.8.1 - 8e8befb1 - 2025-04-10 15:46:39