How to access and clean Application Error Log programmatically?

Hi, not sure about Cache2017 but in later versions there is a TaskMgr task available to purge application error logs, afaik this is automatically configured to purge any application errors older than 30days.
%SYS.Task.PurgeErrorsAndLogs - InterSystems IRIS Data Platform 2025.1 - including private class members
 

You can delete the application error logs for all days by executing the below code for specific namespace 

ClassMethod DeleteAppErrorLog(Namespace As%String = {$Namespace}) As%Status
{
    New$NamespaceSet$Namespace = "%SYS"Return##class(SYS.ApplicationError).DeleteByNamespace(Namespace)
}

Delete by date

ClassMethod DeleteAppErrorLogByDT(pNamespace As%String = {$Namespace},pDate ={$ZD(+$H)}) As%Status
{
    New$NamespaceSet$Namespace = "%SYS"Return##class(SYS.ApplicationError).DeleteByDate(pNamespace,pDate)
}

Hi, I wrote some code to access the ^ERROR global from a character based screen some years ago because the GUI was too slow and cumbersome. There's too much code to share on here but I can give you some direction on the global layout:

The location of ^ERRORS varies between current namespace and %SYS. I haven't looked in to why, it might be due to Caché version. This full program works from Caché 5 through to 2018.

ClassMethod START(test = 0) As %String{ S NSP=$ZNSPACE,%ENSP=NSP ; Error global namespace could be "%SYS" or local namespace, haven't worked out how it changes I test S NSP="%SYS",%ENSP=NSP ; ; work out where the ^ERRORS global is i $D(^ERRORS) {  ; it's in the current namespace  S %ENSP=NSP ; location of the error global } ElseIf $D(^["%SYS"]ERRORS) {  S %ENSP="%SYS" } ; count the number of errors for this namespace by date. Date is $H S Date="" F  {  S Date=$O(^[%ENSP]ERRORS(Date),-1) q:Date=""

Errors with a date are given a sequence number starting at 1 for the first error

{ S ERN="" F  {  S ERN=$O(^[%ENSP]ERRORS(Date,ERN)) Q:ERN=""  ; STACK 0 has got most of what we need to see right now  S NSPACE=$g(^[%ENSP]ERRORS(Date,ERN,"*STACK",0,"V","$ZU( 5)"))  I NSP=NSPACE,$I(COUNT) {; sort by time, latest to earliest
   ; stack 0 contains environment variables like $I, $J, etc.    S Time=$g(^[%ENSP]ERRORS(Date,ERN,"*STACK",0,"V","$H"))   S Username=$g(^[%ENSP]ERRORS(Date,ERN,"*STACK",0,"V","$USERNAME"))   S ZE=$g(^[%ENSP]ERRORS(Date,ERN,"*STACK",0,"V","$ZE"))

Further stack levels contain variables (including arrays and objects) and other stack information

S changePoint=$G(^[%ENSP]ERRORS(Date,ERN,"*STACK",Stack,"L"))s var=$o(^[%ENSP]ERRORS(Date,ERN,"*STACK",Stack,"V",var),1,value) q:var=""i $D(^[%ENSP]ERRORS(Date,ERN,"*STACK",Stack,"V",var))#2 { s ZR=$ZR i $p(value,"0 ",2)'="",..ListValid($p(value,"0 ",2)) {  ; looks like a status code   //" "_var_" = (status code - fail...)")} else {  // (" "_var_" = "_value)} i value["<OBJECT REFERENCE>[" {  d ..ShowObject(ScreenObj3,ZR,.i,0)  } } // Variables that are arrays i $D(^[%ENSP]ERRORS(Date,ERN,"*STACK",Stack,"V",var,"N"))>1{  s subs=""  f j=1:1 {   s subs=$O(^[%ENSP]ERRORS(Date,ERN,"*STACK",Stack,"V",var,"N",subs),1,value)   q:subs=""   //(" "_var_"("_subs_") = "_value))

Objects are stored thus

ClassMethod ShowObject(ScreenObj3 As ZSS.Screen, ZRef, ByRef i, expand = 1){ S Date=$QS(ZRef,1) S ERN=$QS(ZRef,2) S Stack=$QS(ZRef,4) S var=$QS(ZRef,6) S value=@ZRef ; should be immediately followed by "OREF",1)=no of lines ; and "OREF",1,0)=something I don't know - could be a character count ; then loads of rows where each line is terminated by $C(13,10) ; re-add with expand/collapse marker s sign=$s(expand:" - ",1:" + ") //$LB(sign_var_" = "_value),$LB("OBJECT",ZRef)) i expand {  s row=""  f line=1:1:$G(^[%ENSP]ERRORS(Date,ERN,"*STACK",Stack,"V",var,"OREF",1)) {   s row=row_$G(^[%ENSP]ERRORS(Date,ERN,"*STACK",Stack,"V",var,"OREF",1,line))   i $E(row,$l(row)-1,9999)=$c(13,10) {   //$LB(" "_$e(row,0,$l(row)-2)))   s row=""   }  } }

Once you've understood the global layout it wouldn't take a lot to kill off dates that you are not interested in any longer. I haven't needed to.