Articoli

A SQL Server DBA Myth a day In questa serie di posts di Paul Randal vengono sfatati alcuni “miti” diffusi tra i DBA SQL Server.

(1/30) in-flight transactions continue after a failover (2/30) DBCC CHECKDB causes blocking (3/30) instant file initialization can be controlled from within SQL Server (4/30) DDL triggers are INSTEAD OF triggers (5/30) AWE must be enabled on 64-bit servers (6/30) three null bitmap myths (7/30) multiple mirrors and log shipping load delays (8/30) unicorns, rainbows, and online index operations (9/30) data file shrink does not affect performance (10/30) database mirroring detects failures immediately (11/30) database mirroring failover is instantaneous (12/30) tempdb should always have one data file per processor core (13/30) you cannot run DMVs when in the 80 compat mode (T-SQL Tuesday #005) (14/30) clearing the log zeroes out log records (15/30) checkpoint only writes pages from committed transactions (16/30) corruptions and repairs (17/30) page checksums (18/30) FILESTREAM storage, garbage collection, and more (19/30) TRUNCATE TABLE is non-logged (20/30) restarting a log backup chain requires a full database backup (21/30) corruption can be fixed by restarting SQL Server (22/30) resource governor allows IO governing (23/30) lock escalation (24/30) twenty six restore myths (25/30) fill factor (26/30) nested transactions are real (27/30) use BACKUP WITH CHECKSUM to replace DBCC CHECKDB (28/30) BULK_LOGGED recovery model (29/30) fixing heap fragmentation (30/30) backup myths

Ancora Glenn Berry nella sua serie di posts dedicati all’hardware: utile punto di partenza per chi sta per scegliere il server da acquistare per SQL Server. La serie è del 2011, ma molti posts sono ancora attuali. Per chi necessita di informazioni ancora più recenti, vi rimando al blog di Glenn.

In questa serie di posts di Jonathan Kehayias si parla di come utilizzare gli Extended Events per monitorare SQL Server.

(1 of 31) - An Overview of Extended Events (2 of 31) - Querying the Extended Events Metadata (3 of 31) - Managing Event Sessions (4 of 31) - Querying the Session Definition and Active Session DMV’s (5 of 31) - Targets Week - ring_buffer (6 of 31) - Targets Week - asynchronous_file_target (7 of 31) - Targets Week - bucketizers (8 of 31) - Targets Week - synchronous_event_counter (9 of 31) - Targets Week - pair_matching (10 of 31) - Targets Week - etw_classic_sync_target (11 of 31) - Targets Week - Using multiple targets to simplify analysis (12 of 31) - Using the Extended Events SSMS Addin (13 of 31) - The system_health Session (14 of 31) - A Closer Look at Predicates (15 of 31) - Tracking Ghost Cleanup (16 of 31) - How Many Checkpoints are Issued During a Full Backup? (17 of 31) - A Look at Backup Internals and How to Track Backup and Restore Throughput (Part 1) (18 of 31) - A Look at Backup Internals and How to Track Backup and Restore Throughput (Part 2) (19 of 31) - Using Customizable Fields (20 of 31) - Mapping Extended Events to SQL Trace (21 of 31) - The Future - Tracking Blocking in Denali (22 of 31) - The Future - fn_dblog() No More? Tracking Transaction Log Activity in Denali (23 of 31) - How it Works - Multiple Transaction Log Files (24 of 31) - What is the package0.callstack Action? (25 of 31) - The Twelve Days of Christmas (26 of 31) - Configuring Session Options (27 of 31) - The Future - Tracking Page Splits in SQL Server Denali CTP1 (28 of 31) - Tracking Page Compression Operations (29 of 31) - The Future - Looking at Database Startup in Denali (30 of 31) - Tracking Session and Statement Level Waits (31 of 31) - Event Session DDL Events

In questa serie di posts Ted Krueger riporta i principali “tips” per chi amministra SQL Server.

SQL Server DBA Tip 1 - Server Configuration - MAX Memory SQL Server DBA Tip 2 - Server Configuration - Data/Log Files SQL Server DBA Tip 3 - Server Configuration - Model Database SQL Server DBA Tip 4 - Server Considerations - 32 bit / 64 bit SQL Server DBA Tip 5 - Server Considerations - Installing Features (SSIS, SSRS, Engine, SSAS) SQL Server DBA Tip 6 - Server Security - Windows Authentication / SQL Authentication SQL Server DBA Tip 7 - Server Security and grouping - Schema Control SQL Server DBA Tip 8 - Server Monitoring - Baseline SQL Server DBA Tip 9 - SQL Server Monitoring - Default Trace SQL Server DBA Tip 10 - SQL Server Reporting - Offload the reporting factor SQL Server DBA Tip 11 - SQL Server Configuration - MIN Memory SQL Server DBA Tip 12 - SQL Server Tuning - Missing Index DMV SQL Server DBA Tip 13 - SQL Server built in DR/HA Solutions SQL Server DBA Tip 14 - SQL Server General - Updating Production Data SQL Server DBA Tip 15 - SQL Server Agent - Job ownership SQL Server DBA Tip 16 - Working with Files and Folders

Beh, non propriamente uno al giorno, ma comunque utilissimi per comprendere alcuni dei meccanismi “dietro le quinte” di SQL Server

#1 March 2011: RESTART option for RESTORE commands (video | demo code) #2 March 2011: Logging during SELECT-INTO operations (video | demo code) #3 April 2011: Undocumented DBCC commands (video | demo code) #4 April 2011: Log file performance analysis (video | demo code) #5 May 2011: Nested transactions (video | demo code) #6 May 2011: Checkpoint tracking (video | demo code) #7 May 2011: Trusting the tools - Kimberly (video) #8 June 2011: Tempdb latch contention (video | demo code) #9 June 2011: Wait stats for a single operation (video | demo code) #10 July 2011: Database snapshots (video | demo code) #11 July 2011: Undroppable log files (video | demo code) #12 August 2011: Tail-of-the-log backups (video | demo code) #13 August 2011: Error log management (video) #14 September 2011: Inconsistent analysis (video | demo code) #15 October 2011: Fully logged operations (video | demo code) #16 October 2011: Tempdb space tracking (video | demo code) #17 October 2011: Deadlock analysis - Joe (video | demo code) #18 November 2011: Query timeout debugging (video | demo code) #19 December 2011: Deadlock debugging - Joe (video | demo code)

Steve Swartz, Group Program Manager SSIS Team, in una delle sessioni che ha tenuto al TechEd Europe 2010 ha parlato di SSIS Tips & Tricks.

Se state lavorando a un nuovo progetto con SQL Server Integration Services o se dovete migliorare le performance di un progetto (insieme di package) esistente, ma non avete tempo a sufficienza o risorse economiche per iniziare da zero il tuning delle performance, vi consiglio di investire 60 minuti guardando questo webcast.

A volte può capitare di dover collegare tra loro più resultset, ad esempio tramite il component Merge Join. Alcune trasformazioni necessitano di ricevere set di input ORDINATI. Quando questi input sono considerati ordinati? SSIS riesce a comprenderlo tramite una proprietà: IsSorted.

http://www.dotnethell.it/tips/SSIS-IsSorted-Property.aspx