Microsoft SQL Server 2025

This is an advent blog series on new functionalities in SQL Server 2025 as fun and educational way of christmas gifts and advent calendar :-)

• Dec 01: Microsoft SQL Server 2025 – Introduction and installation
• Dec 02: Microsoft SQL Server 2025 New T-SQL functions - native JSON data type and some functions
• Dec 03: Microsoft SQL Server 2025 – New T-SQL functions – JSON Index
• Dec 04: Microsoft SQL Server 2025 – New T-SQL functions – Product()
• Dec 05: Microsoft SQL Server 2025 - New T-SQL functions - BASE64_ENCODE() and BASE64_DECODE()
• Dec 06: Micosoft SQL Server 2025 – New T-SQL functions – REGEXP_LIKE()
• Dec 07: Micosoft SQL Server 2025 – New T-SQL functions – REGEXP_SUBSTR() and REGEXP_REPLACE()
• Dec 08: Micosoft SQL Server 2025 – New T-SQL functions – REGEXP_INSTR() and REGEXP_COUNT()
• Dec 09: Microsoft SQL Server 2025 – New T-SQL functions – REGEXP_MATCHES() and REGEXP_SPLIT_TO_TABLE()
• Dec 10: Microsoft SQL Server 2025 – External REST endpoint invocation
• Dec 11: Microsoft SQL Server 2025 – External REST endpoint invocation using LLM
• Dec 12: Microsoft SQL Server 2025 – New vector data type and Vector functions
• Dec 13: Microsoft SQL Server 2025 – Vector functions
• Dec 14: Microsoft SQL Server 2025 – Vector arrays or embeddings with function AI_GENERATE_EMBEDDINGS
• Dec 15: Microsoft SQL Server 2025 – T-SQL functions for AI External_Models, Chunks and Embeddings
• Dec 16: Microsoft SQL Server 2025 – Optional parameter plan optimization (OPPO)
• Dec 17: Microsoft SQL Server 2025 – Query hint ABORT_QUERY_EXECUTION
• Dec 18: Microsoft SQL Server 2025 – Optimized locking
• Dec 19: Microsoft SQL Server 2025 – New T-SQL functions – CURRENT_DATE
• Dec 20: Microsoft SQL Server 2025 – Change Event Streaming
• Dec 21: Microsoft SQL Server 2025 – Change Event Streaming – part 2
• Dec 22: Microsoft SQL Server 2025 – T-SQL Features – UNISTR()
• Dec 23: Microsoft SQL Server 2025 – T-SQL Features – String concatenation with || and compound assignment ||=
• Dec 24: Microsoft SQL Server 2025 – Documentation and learning materials

• T-SQL

  • RegEx
  • PRODUCT()
  • Current_date
  • fuzzy string matching
  • unistr()
  • string concat operator ||
  • base64 functions
  • substring() (optinal length)
  • dateadd suppots bigint

• API (sp_invoke_external_rest_api)

• CES (Change event streaming) (Compare CT, CDC and CES)

• Fabric Mirroring

• Core engine

  • Security

    • Security cache improvements
    • AEP support for encryption
    • PBKDF password hashing
    • Authentication using system-assigned managed identity
    • Backup to URL with managed identity
    • Managed identity support for EKM
    • Managed identity for AI models
    • Entra logins with nonunique display names
    • Custom password policy on Linux
    • TDS 8.0/TLS 1.3 support for tools

  • Performance

    • Optimized Locking
    • Tempdb space resource governance
    • ADR in tempdb
    • Persisted stats for readable secondaries
    • Change tracking cleanup
    • Columnstore index maintenance
    • CE feedback for expressions
    • Optional parameter plans optimization
    • DOP feedback on by default
    • Optimized Halloween protection
    • Query store for readable secondaries
    • ABORT_QUERY_EXECUTION query hint
    • Optimized sp_executesql
    • Batch mode optimizations
    • Remove In-Memory OLTP from a database
    • tmpfs support for tempdb in Linux

  • HADR

    • Fast failover for persistent AG Health
    • Async page request dispatching
    • Improved health diagnostics
    • Communication control flow tuning
    • Switching to resolving state
    • Remove listener IP address
    • NONE for routing
    • AG group commit waiting tuning
    • Contained AG support for DAG
    • DAG sync improvements
    • Backups on secondary replicas
    • ZSTD Backup compression
    • Backup to Azure immutable storage