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Foglight for SQL Server (Cartridge) 6.3.0 - User Guide

Introduction to this Guide Using Foglight for SQL Server
Viewing the Databases Dashboard Overview Dashboard Advisories Dashboard Monitoring Data Replication Monitoring SQL Performance Reviewing Memory Usage Reviewing the Instance Activity Reviewing Database Usage Reviewing the Services Using the HADR Drilldown Using the Logs Drilldown Reviewing Configuration Settings Viewing User-defined Performance Counters and Collections
Monitoring Business Intelligence Services Administering Foglight for SQL Server
Configuration Settings Managing Foglight for SQL Server Agent Settings Reviewing Foglight for SQL Server Alarms Generating Reports Monitoring SQL Server instances on VMware servers
Glossary
A
Access methods Adhoc SQL Plans Alarm Alert Allow updates Anonymous subscription Authentication AutoClose AutoGrow Automatic Discovery AutoShrink B Batch BCP (Bulk Copy Program) Blocking Books Online Bound trees Buffer Buffer cache Buffer pool Bulk copy Bulkinsert Bulk load C Cache CAL Calibration Cardinality Cartridge Chart Checkpoint process Client network utility CLR Compile Connect Connection Connectivity software CPU Usage Cursors D Data access components Data file Data storage engine Database Database object DataFlow DBCC DBID DBO Deadlock Disk queue length Disk transfer time Disk utilization DiskPerf Distributing instance Distributor DMO Drilldown DTC DTS E Error log Event alert Execution contexts Extended stored procedures Extent External procedures F File Filegroup File cache Foglight Agent Manager Foglight Management Server Foreign key Forwarded records Free buffers Free list Free pages Free potential Free space Freespace scans Full text search G GAM Ghosted records Growth increment GUID H Hash buckets Hashing Heap Hit rate Hit ratio Host name Host process I I/O Index Indid Integrated security Intent Locks J Job K Kernel memory Kernel mode Kill L Latch Lazy writer Licensing Lightweight pooling Lock Lock area Lock escalation Lock mode Log Log cache Log writer Logical I/O LRU LSN M Master MaxSize MDAC Metric Misc.normalized trees Model Monitor page file N Named pipes Net library NIC Null O OBID Object plans OLAP OLAP service OLTP Optimizer Optimizer cache osql P Page life expectancy Paging Panel Parse Parser Per seat licensing Per server licensing Performance alert Physical I/O Physical read Physical write PID Pinned Plan Plan cache Potential growth Prepared SQL plans Primary key Privileged mode Procedure cache Procedure plans Process Profiler Publication database Publisher Publisher databases Publishing server Pull subscription Pulse Push subscription Q Query plan R RAID Random I/O Read ahead Recompile Referential integrity Relational data engine Replication procedure plans Role Rollback S sa Schema locks Sequential I/O Session Severity SGAM Shared locks Show advanced options SMP Sort, Hash, Index Area SPID Spike Spinner SQL Agent Mail SQL Mail SQL Plans SQL Server Agent SQL Server authentication SQL Server books online Standard deviation Stolen pages Stored procedure Support service SYSADMIN role T TDS TempDB Temporary tables and table variables Threshold Torn page detection Transaction Trigger Trigger plans Truncate Trusted U UMS Unused space User connection area User mode V Virtual log file VLF W Waitfor Windows authentication mode Working set
Reference
SQL Performance Investigator Metrics
Active Time All SQL Agents CPU Usage All SQL Agents Resident Memory Usage Availability Average Physical I/O Operations Average SQL Response Time Backup Recovery Wait Blocked Lock Requests Checkpoint Pages CLR Wait CPU Usage CPU Wait Cursor Synchronization Wait Database Replication Wait Deferred Task Worker Wait Degree of Parallelism Disk Utilization DTC CPU Usage DTC Resident Memory Usage Distributed Transaction Wait Executions Ended Executions Started External Procedures Wait Full Scans Full Text Search CPU Usage Full Text Search Resident Memory Usage Full Text Search Wait Free Buffer Wait Hosted Components Wait IO Bulk Load Wait IO Completion Wait IO Data Page Wait IO Wait Latch Buffer Wait Latch Wait Latch Savepoint Wait Lazy Writes Lock Wait Lock Bulk Update Wait Lock Exclusive Wait Lock Intent Wait Lock Requests Lock Schema Wait Lock Shared Wait Lock Update Wait Lock Wait Log Buffer Wait Log Flushes Log Other Wait Log Synchronization Wait Log Wait Log Write Wait Memory Wait Network IO Wait Network IPC Wait Network Mirror Wait Network Wait Non SQL Server CPU Usage Non SQL Resident Memory Usage OLAP CPU Usage OLAP Resident Memory Usage OLEDB Provider Full Text Wait Other CPU Usage Other Miscellaneous Wait Other Wait Overall CPU Page Life Expectancy Page Splits Parallel Coordination Wait Physical I/O Physical Memory Used Physical Page Reads Physical Page Writes Probe Scans Plan Cache Hit Rate Range Scans Rec Ended Duration Remote Provider Wait Run Queue Length Samples Service Broker Wait Session Logons Session Logoffs SQL Agent CPU Usage SQL Agent Resident Memory Usage SQL Executions SQL Mail CPU Usage SQL Mail Resident Memory Usage SQL Recompilations SQL Response Time SQL Server Background CPU Usage SQL Server Cache Memory SQL Server Connections Memory SQL Server Connections Summary SQL Server Foreground CPU Usage SQL Server Resident Memory Usage SQL Server Swap Memory Usage Synchronous Task Wait Table Lock Escalation Target Instance Memory Total CPU Usage Total Instance Memory Virtual Memory Used
Rules Collections and Metrics
SQL Server Agent's Default Collections Access Methods Agent Alert List Agent Job List Always On Availability Groups Backup Locations Blocking History Blocking List Buffer Cache List Buffer Manager CLR Assemblies Cluster Summary Configuration Database Index Density Vectors Database Index Details Database Index Fragmentation Info Database Index Histogram Database Index List Database Information Database Properties Database Sessions (Session List) Database Summary Database Tables List Databases Deadlock DTC Information Error Log Error Log List Error Log Scan File Groups File Data Flow Statistics File Groups Files Files Drive Total Files Instance Summary Full Text Catalog InMemory OLTP (XTP) Instance Wait Categories Instance Wait Events Job Messages Latches and Locks Lock Statistics Locks List Log Shipping Log Shipping Error Logical Disks Long Running Session Memory Manager Mirroring Mirroring Performance Counters Missing Indexes Plan Cache Distribution Plan Cache List Replication Agents Replication Agent Session Actions Replication Agent Session Merge Articles Replication Agent Sessions Replication Agent Sessions by Type Replication Available Replication Publications Replication Subscriptions Reporting Services Resource Pool Session Data Session Trace SQL PI Instance Statistics SQL Server Connections Summary SQL Server Global Variables SQL Server Host SQL Server Load SQL Server Services SQL Server Throughput SQL Server Version Info SSIS OS Statistics SSIS Summary Statistics Top SQLs Top SQL Batch Text Top SQL Long Text Top SQL Plan Top SQL Short Text Top SQL Summary Traced SQL PA Usability User-defined Performance Counters User-defined Queries Virtualization XTP Session Transactions Statistics

Tracking logical reads

The flow from the SQL Memory pane to the SQL Processes pane indicates the rate at which pages in the buffer cache are being referenced by SQL connections (logical page reads).

Normally, the majority of logical reads is satisfied from the cache, but if the required page is not yet in the cache, it is read from disk.

For details, see Viewing the SQL Server I/O activity .

Tracking compiles

The Compiles flow displays the rate of SQL compilations and recompilations per second.

Preferably, the most frequently used executable query plans should be retrieved from the procedure cache, thereby saving the need to compile, significantly reducing the utilization of CPU resources, and speeding up the response time of SQL Server queries. Recompiling, which is a CPU-intensive process that may degrade performance, can in certain cases be avoided through sound coding practices.

When many recompiles take place, the SQL Server’s CPU can become overloaded, thereby slowing down everything running on that computer. As a result, the Recompiles alarm is invoked. For details, see Recompiles Alarm .

The Call Rates chart, displayed in the SQL Instance Summary panel of the SQL Activity drilldown, details the use of compiles and re-compiles during the last 60 minutes. For details, see Monitoring the call rates .

Monitoring the SQL memory management

The Memory Activity pane allows monitoring the SQL Server’s dynamic memory management and ensuring its proper handling of the buffer pool.

Each page of memory used by SQL Server is assigned to one of several cache types. Each cache grows and shrinks in size as required. The main caches are the Buffer Cache, which stores a copy of the SQL Server’s most recently used database pages, and the Procedure Cache, which holds recently compiled query execution plans. Both these cache types should satisfy I/O requests and save the need for physical reads from the disk. The Buffer cache’s efficiency also affects the Page Life Expectancy, another indicator displayed in the SQL Memory pane.

 
Table 17. The SQL Memory pane displays the following parameters:
Summary section
Total (MB)

The total amount of memory, either fixed or dynamically allocated, which the SQL Server is currently using.

When the amount of SQL Server memory available for immediate reuse drops below a threshold, the Free Buffers alarm is invoked. For details, see Free Buffers Alarm .

Memory Used

Displays the total amount of memory, either fixed or dynamically allocated, that the SQL server is currently consuming, scaled against the maximum amount of memory it can use.

By default, SQL Server manages its total memory automatically, adjusting it to the varying memory requests of both SQL Server processes and Windows processes.

Clicking this gauge allows accessing the Memory > Buffer Cache panel, which provides an in-detail view of SQL Server’s memory management. For details, see Viewing the Memory Summary .

Plan Cache Section
Total

Displays the amount of memory currently allocated to the plan cache (formerly known as procedure cache), a memory area used by SQL Server to hold recently compiled query execution plans stored procedures, triggers, ad hoc SQL, and so on.

The value of this metric is calculated as follows:

<pages> * 8K / 1024

Hit Rate

Displays the percentage of plan cache lookups that found the required plan already in the cache.

If a matching plan is found, SQL Server does not need to compile the query/stored procedure. This can save a significant amount of CPU resources, and can speed up SQL Server queries.

A low Plan Cache hit rate may lead to performing extra compilations, thereby degrading SQL Server performance by causing extra CPU load. In a such situation, the Procedure Cache Hit Ratio Alarm is invoked. For details, see Procedure Cache Hit Ratio Alarm .

The plan cache hit rate is the average hit rate for all procedure cache object types, except for ad hoc SQL. This rate is calculated using a differential sampling method, which gauges only the last few sampled periods.

Buffer Cache Section
Total

Displays the amount of memory currently allocated to the buffer cache, including database, free, and stolen pages.

The buffer cache, which is an in-memory copy of recently used database pages, is normally the largest memory cache used by SQL Server. If an SQL process needs to access a database page, finding this page in the buffer cache spares the SQL Server the need to read the page from disk, thereby significantly reducing the amount of disk I/O and speeding up queries.

The value of this metric is calculated as follows:

<pages> * 8K / 1024

Hit Rate

Displays the percentage of database page I/O requests that were satisfied from the buffer cache.

High buffer cache hit rate indicates that SQL Server efficiently uses the memory allocated to its buffer cache. Low buffer cache hit rate, on the other hand, indicates that SQL Server is finding fewer pages already in memory, resulting in the need to perform more disk reads.

Low buffer cache hit rate invokes the Buffer Cache Hit Ratio alarm. For details, see Buffer Cache Hit Ratio Alarm .

Page Life Expectancy

Displays the current Page Life Expectancy, that is, the length of time in seconds that a database page stays in the buffer cache before it is flushed out.

Small values indicate that the buffer cache retains pages for short periods, as a result of high data cycling, and that the buffer cache is not being effective.

Microsoft recommends 300 seconds as the minimum value for this metric; any less is indicative of a shortage of memory.

For details, see Page Life Expectancy Alarm .

Tracking physical I/O activity

The physical I/O Operations section of the Foglight for SQL Server Instance Homepage displays graphical representations of the number of pages physically read from and written to disk by SQL Server.

In addition, this section allows viewing the SQL Server processes Checkpoint and Lazy Writes.

 
 
Parameter
Description
Physical Writes

A flow that represents data/index pages written to disk per second. Normally, SQL users do not have to wait for database write operations to complete, as most modifications to database pages are made in the buffer cache.

Physical Reads

A flow that represents page reads from the disk per second.

Physical reads are used when a connection requests a page that is not already in the buffer cache.

Physical read operations are necessary when accessing new table or index pages. Nevertheless, these operations should be avoided when possible, as requested pages should reside in the SQL Server buffer cache.

Log Flushes

A flow that represents the number of log pages per second being written to disk by the Log Writer process. For details, see the glossary definition of Log writer .

For details, see Monitoring the SQL Server physical I/O activity .

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