Log SQL Server Reference Documentation

Log

Current Version: 11.6.0

Chilkat.Log

Build readable structured diagnostic logs with nested context and tagged values.

Chilkat.Log is a lightweight structured logging helper for creating readable diagnostic logs from application code. It can record nested operation contexts, informational messages, error messages, timestamps, integers, 64-bit integers, tagged values, binary data, Base64 data, hex data, shortened data previews, and computed hashes. It is useful when code needs a clear step-by-step record of operations, inputs, outputs, and diagnostic values for troubleshooting.

Nested operation context

Use EnterContext and LeaveContext to group log entries under readable operation names.

Messages and errors

Add informational messages, error messages, and tagged text values to explain what the application is doing.

Numbers and timestamps

Log integers, 64-bit integers, timestamps, and date/time values when tracing state changes or timing-sensitive workflows.

Binary diagnostics

Record binary data as Base64, hex, or shortened previews so byte-level values can be inspected safely in text logs.

Hash logging

Compute and log hashes of data when comparing content, verifying transformations, or avoiding full data dumps.

Clear and reuse

Clear the log and continue building new diagnostic output during repeated operations or test runs.

Common pattern: Create a Log object, enter a named context for the operation, log the important values and decisions as the code runs, leave the context, and inspect the resulting text if troubleshooting is needed. Use Chilkat.Log for application-level diagnostic output; use LastErrorText on Chilkat objects for detailed diagnostics from Chilkat method calls.

Object Creation

DECLARE @hr int
DECLARE @log int
EXEC @hr = sp_OACreate 'Chilkat.Log', @log OUT
IF @hr <> 0
BEGIN
    PRINT 'Failed to create ActiveX component'
    RETURN
END

-- ... use @log ...

EXEC @hr = sp_OADestroy @log

T-SQL uses the Chilkat ActiveX through the OLE Automation stored procedures. They must be enabled once on the server (EXEC sp_configure 'Ole Automation Procedures', 1; RECONFIGURE;), and the Chilkat ActiveX registered must match the bitness of the SQL Server instance (64-bit for a 64-bit SQL Server). To bind to a specific major version of Chilkat, append the major version number to the ProgID, such as sp_OACreate 'Chilkat.Log.11' for Chilkat v11.*.*.

sp_OACreate returns an object token (an int) that is passed as the first argument of every sp_OAMethod, sp_OAGetProperty and sp_OASetProperty call, and released with sp_OADestroy. Objects returned by methods (such as an HttpResponse or JsonObject) are also tokens received through an int OUT parameter; they must likewise be destroyed, and the OUT parameter is NULL when the method fails to return an object. Objects passed as arguments are passed by their token. When an OLE Automation procedure itself fails (non-zero @hr), sp_OAGetErrorInfo describes the error.

Data types: strings are nvarchar(4000); integers, booleans (1 or 0) and object tokens are int; dates are datetime. In the signatures on this page, @success, @iResult, @sResult and the like are the OUT variables receiving a method's return value, @iValue / @sValue receive or supply a property value, and the remaining @ variables are the method's arguments in order.

A string returned through an OUT parameter is limited to 4000 characters. For longer values, retrieve the result as a result set into a table variable instead of an OUT parameter, for example DECLARE @tmp TABLE (outputLine ntext) followed by INSERT INTO @tmp EXEC sp_OAGetProperty @log, 'LastErrorText'. See string length limitations for strings returned by sp_OAMethod calls.

Methods that pass or return raw byte arrays are not shown on this page, because varbinary(max) values cannot be exchanged through sp_OAMethod (see varbinary(max) limitation). Use the BinData-based alternatives (methods ending in Bd) or the base64 / hex string-encoded variants instead. Binary properties (such as LastBinaryResult) can be retrieved as a result set into a table variable, as shown in their signatures. Asynchronous (*Async) methods and event callbacks are not available from SQL Server.

Properties

DebugLogFilePath
EXEC sp_OAGetProperty @log, 'DebugLogFilePath', @sValue OUT
EXEC sp_OASetProperty @log, 'DebugLogFilePath', @sValue

If set to a file path, this property logs the LastErrorText of each Chilkat method or property call to the specified file. This logging helps identify the context and history of Chilkat calls leading up to any crash or hang, aiding in debugging.

Enabling the VerboseLogging property provides more detailed information. This property is mainly used for debugging rare instances where a Chilkat method call causes a hang or crash, which should generally not happen.

Possible causes of hangs include:

  • A timeout property set to 0, indicating an infinite timeout.
  • A hang occurring within an event callback in the application code.
  • An internal bug in the Chilkat code causing the hang.

More Information and Examples
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LastBinaryResult
INSERT INTO @tmp EXEC sp_OAGetProperty @log, 'LastBinaryResult'

This property is mainly used in SQL Server stored procedures to retrieve binary data from the last method call that returned binary data. It is only accessible if Chilkat.Global.KeepBinaryResult is set to 1. This feature allows for the retrieval of large varbinary results in an SQL Server environment, which has restrictions on returning large data via method calls, though temp tables can handle binary properties.

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LastErrorHtml
EXEC sp_OAGetProperty @log, 'LastErrorHtml', @sValue OUT

Provides HTML-formatted information about the last called method or property. If a method call fails or behaves unexpectedly, check this property for details. Note that information is available regardless of the method call's success.

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LastErrorText
EXEC sp_OAGetProperty @log, 'LastErrorText', @sValue OUT

Provides plain text information about the last called method or property. If a method call fails or behaves unexpectedly, check this property for details. Note that information is available regardless of the method call's success.

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LastErrorXml
EXEC sp_OAGetProperty @log, 'LastErrorXml', @sValue OUT

Provides XML-formatted information about the last called method or property. If a method call fails or behaves unexpectedly, check this property for details. Note that information is available regardless of the method call's success.

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LastMethodSuccess
EXEC sp_OAGetProperty @log, 'LastMethodSuccess', @iValue OUT
EXEC sp_OASetProperty @log, 'LastMethodSuccess', @iValue

Indicates the success or failure of the most recent method call: 1 means success, 0 means failure. This property remains unchanged by property setters or getters. This method is present to address challenges in checking for null or Nothing returns in certain programming languages. Note: This property does not apply to methods that return integer values or to boolean-returning methods where the boolean does not indicate success or failure.

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LastStringResult
EXEC sp_OAGetProperty @log, 'LastStringResult', @sValue OUT

In SQL Server stored procedures, this property holds the string return value of the most recent method call that returns a string. It is accessible only when Chilkat.Global.KeepStringResult is set to TRUE. SQL Server has limitations on string lengths returned from methods and properties, but temp tables can be used to access large strings.

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LastStringResultLen
EXEC sp_OAGetProperty @log, 'LastStringResultLen', @iValue OUT

The length, in characters, of the string contained in the LastStringResult property.

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VerboseLogging
EXEC sp_OAGetProperty @log, 'VerboseLogging', @iValue OUT
EXEC sp_OASetProperty @log, 'VerboseLogging', @iValue

If set to 1, then the contents of LastErrorText (or LastErrorXml, or LastErrorHtml) may contain more verbose information. The default value is 0. Verbose logging should only be used for debugging. The potentially large quantity of logged information may adversely affect peformance.

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Version
EXEC sp_OAGetProperty @log, 'Version', @sValue OUT

Version of the component/library, such as "10.1.0"

More Information and Examples
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Methods

Clear
EXEC sp_OAMethod @log, 'Clear', NULL, @initialTag
Introduced in version 9.5.0.44

Clears all existing log entries and starts a new log whose top-level context is named initialTag.

Typical use: Call this at the beginning of an operation or test run, then add entries with the other Log* methods. The completed structured log can be inspected through the Log object's diagnostic text, such as LastErrorText.
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EnterContext
EXEC sp_OAMethod @log, 'EnterContext', NULL, @tag
Introduced in version 9.5.0.44

Begins a nested logging context named tag. Entries written after this call are grouped inside the new context until a matching LeaveContext is called.

Balanced contexts: Pair each EnterContext with LeaveContext. Contexts may be nested to reflect operation hierarchy.
More Information and Examples
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LeaveContext
EXEC sp_OAMethod @log, 'LeaveContext', NULL
Introduced in version 9.5.0.44

Ends the current nested logging context and returns logging to its parent context.

Empty contexts are omitted: If nothing was logged after entering the current context, Chilkat automatically removes that empty context when it is left.
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LogData
EXEC sp_OAMethod @log, 'LogData', NULL, @tag, @message
Introduced in version 9.5.0.44

Adds a tagged text value to the current context. The output associates tag with message, making this useful for named values such as filenames, paths, IDs, states, or protocol fields.

Sensitive data: Avoid logging passwords, private keys, access tokens, session secrets, or other sensitive values unless disclosure is intentional.
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LogDataMax
EXEC sp_OAMethod @log, 'LogDataMax', NULL, @tag, @message, @maxNumChars
Introduced in version 9.5.0.44

Adds a tagged text value to the current context, but limits the logged value to at most the first maxNumChars characters of message.

Diagnostic previews: Use this when a value may be very large and only a leading preview is needed. The original input string is not modified.
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LogDateTime
EXEC sp_OAMethod @log, 'LogDateTime', NULL, @tag, @gmt
Introduced in version 9.5.0.44

Logs the current date and time under tag using an RFC 822-style date/time representation. If gmt is 1, the logged time is GMT/UTC; otherwise local system time is used.

Date/time vs. timestamp: Use LogDateTime for a calendar date with timezone context. Use LogTimestamp for a time-of-day marker.
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LogError
EXEC sp_OAMethod @log, 'LogError', NULL, @message
Introduced in version 9.5.0.44

Adds message as an error entry in the current logging context.

Application diagnostics: This is application-defined logging. It is separate from LastErrorText produced by other Chilkat objects when their operations fail.
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LogInfo
EXEC sp_OAMethod @log, 'LogInfo', NULL, @message
Introduced in version 9.5.0.44

Adds message as an informational entry in the current logging context.

Structured tracing: Use informational entries for significant steps and decisions. Use LogData when the entry is better represented as a named value.
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LogInt
EXEC sp_OAMethod @log, 'LogInt', NULL, @tag, @value
Introduced in version 9.5.0.44

Adds the integer value to the current log under tag.

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LogTimestamp
EXEC sp_OAMethod @log, 'LogTimestamp', NULL, @tag
Introduced in version 9.5.0.44

Logs the current time-of-day under tag in HH:MM:SS:mmm form, where mmm represents milliseconds.

Timing note: This is a time-of-day marker, not a monotonic elapsed-time measurement.
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