Tomcat discards and reloads the jar files from the webapps folder.

classic Classic list List threaded Threaded
7 messages Options
Reply | Threaded
Open this post in threaded view
|

Tomcat discards and reloads the jar files from the webapps folder.

Duca,Cristian
Hello,

We upgraded our tomcat from 7 to 9 and we observed the following:

  *   In tomcat9 the jar files from the webapps folder are discarded and reloaded -> this creates extra input/output operations which increase our CPU Usage.
  *   In tomcat7 the jar files were kept loaded in memory and were not discarded.

I have tried adding the periodicEventDelay set to 0 or a negative value, but we have the same behavior.

Can you please guide me what I can do to have the same behavior as we did with tomcat7.

Thank you,
Cristian Duca.


CONFIDENTIALITY NOTICE This message and any included attachments are from Cerner Corporation and are intended only for the addressee. The information contained in this message is confidential and may constitute inside or non-public information under international, federal, or state securities laws. Unauthorized forwarding, printing, copying, distribution, or use of such information is strictly prohibited and may be unlawful. If you are not the addressee, please promptly delete this message and notify the sender of the delivery error by e-mail or you may call Cerner's corporate offices in Kansas City, Missouri, U.S.A at (+1) (816)221-1024.
Reply | Threaded
Open this post in threaded view
|

Re: Tomcat discards and reloads the jar files from the webapps folder.

markt
On 09/10/2019 11:36, Duca,Cristian wrote:

> Hello,
>
> We upgraded our tomcat from 7 to 9 and we observed the following:
>
>   *   In tomcat9 the jar files from the webapps folder are discarded and reloaded -> this creates extra input/output operations which increase our CPU Usage.
>   *   In tomcat7 the jar files were kept loaded in memory and were not discarded.
>
> I have tried adding the periodicEventDelay set to 0 or a negative value, but we have the same behavior.
>
> Can you please guide me what I can do to have the same behavior as we did with tomcat7.

That depends what resources the web application is attempting to load
from the JAR files.

Mark

---------------------------------------------------------------------
To unsubscribe, e-mail: [hidden email]
For additional commands, e-mail: [hidden email]

Reply | Threaded
Open this post in threaded view
|

RE: Tomcat discards and reloads the jar files from the webapps folder.

Duca,Cristian
Hello,

The web application is trying to load specific classes from the jar files.

The main idea is that in tomcat7 the jar files were kept in memory and when the web application required a specific class the jvm fetched it from memory.
With tomcat9 when the web application requires a specific class tomcat 9 will try to load the jar file which contains that class.

I would like to have the same behavior as we did in tomcat7, is this possible?

Thank you,
Cristian Duca.
-----Original Message-----
From: Mark Thomas <[hidden email]>
Sent: Wednesday, 9 October, 2019 13:39
To: [hidden email]
Subject: Re: Tomcat discards and reloads the jar files from the webapps folder.

On 09/10/2019 11:36, Duca,Cristian wrote:

> Hello,
>
> We upgraded our tomcat from 7 to 9 and we observed the following:
>
>   *   In tomcat9 the jar files from the webapps folder are discarded and reloaded -> this creates extra input/output operations which increase our CPU Usage.
>   *   In tomcat7 the jar files were kept loaded in memory and were not discarded.
>
> I have tried adding the periodicEventDelay set to 0 or a negative value, but we have the same behavior.
>
> Can you please guide me what I can do to have the same behavior as we did with tomcat7.

That depends what resources the web application is attempting to load from the JAR files.

Mark

---------------------------------------------------------------------
To unsubscribe, e-mail: [hidden email]
For additional commands, e-mail: [hidden email]



CONFIDENTIALITY NOTICE This message and any included attachments are from Cerner Corporation and are intended only for the addressee. The information contained in this message is confidential and may constitute inside or non-public information under international, federal, or state securities laws. Unauthorized forwarding, printing, copying, distribution, or use of such information is strictly prohibited and may be unlawful. If you are not the addressee, please promptly delete this message and notify the sender of the delivery error by e-mail or you may call Cerner's corporate offices in Kansas City, Missouri, U.S.A at (+1) (816)221-1024.

---------------------------------------------------------------------
To unsubscribe, e-mail: [hidden email]
For additional commands, e-mail: [hidden email]

Reply | Threaded
Open this post in threaded view
|

Re: Tomcat discards and reloads the jar files from the webapps folder.

markt
On 09/10/2019 11:43, Duca,Cristian wrote:
> Hello,
>
> The web application is trying to load specific classes from the jar files.

Is this genuine class loading (in which case the response below is
correct) or is the application reading the .class files as if they were
resources (in which case a different answer applies)?

> The main idea is that in tomcat7 the jar files were kept in memory and when the web application required a specific class the jvm fetched it from memory.

Not exactly. In Tomcat 7 JAR files are kept open for 90s by default
before being closed and re-opened later if necessary.

> With tomcat9 when the web application requires a specific class tomcat 9 will try to load the jar file which contains that class.

Again, not exactly. In Tomcat 9 JAR files references are cleaned up by
the background processing thread (that triggers various background
tasks). By default this occurs every ~10s.

> I would like to have the same behavior as we did in tomcat7, is this possible?

Yes, but...

You probably only want increase this for a single / all web applications
so you should set backgroundProcessorDelay="90" in the appropriate
context.xml file. This will increase the time between all Context level
background tasks so it will also impact:

- reloading as a result of a modified JAR or class file (this feature is
  disabled by default)

- session expiration

- cleaning of the annotation cache

The impact of these should be minimal but actual impact will depend on
the application.


The standard Manager implementation (via the processExpiresFrequency
attribute) only checks session expiration every 6 calls to
backgroundProcess(). We could add a similar option to StandardRoot that
manages resources so that JAR were files open longer by default.

Mark



>
> Thank you,
> Cristian Duca.
> -----Original Message-----
> From: Mark Thomas <[hidden email]>
> Sent: Wednesday, 9 October, 2019 13:39
> To: [hidden email]
> Subject: Re: Tomcat discards and reloads the jar files from the webapps folder.
>
> On 09/10/2019 11:36, Duca,Cristian wrote:
>> Hello,
>>
>> We upgraded our tomcat from 7 to 9 and we observed the following:
>>
>>   *   In tomcat9 the jar files from the webapps folder are discarded and reloaded -> this creates extra input/output operations which increase our CPU Usage.
>>   *   In tomcat7 the jar files were kept loaded in memory and were not discarded.
>>
>> I have tried adding the periodicEventDelay set to 0 or a negative value, but we have the same behavior.
>>
>> Can you please guide me what I can do to have the same behavior as we did with tomcat7.
>
> That depends what resources the web application is attempting to load from the JAR files.
>
> Mark
>
> ---------------------------------------------------------------------
> To unsubscribe, e-mail: [hidden email]
> For additional commands, e-mail: [hidden email]
>
>
>
> CONFIDENTIALITY NOTICE This message and any included attachments are from Cerner Corporation and are intended only for the addressee. The information contained in this message is confidential and may constitute inside or non-public information under international, federal, or state securities laws. Unauthorized forwarding, printing, copying, distribution, or use of such information is strictly prohibited and may be unlawful. If you are not the addressee, please promptly delete this message and notify the sender of the delivery error by e-mail or you may call Cerner's corporate offices in Kansas City, Missouri, U.S.A at (+1) (816)221-1024.
>
> ---------------------------------------------------------------------
> To unsubscribe, e-mail: [hidden email]
> For additional commands, e-mail: [hidden email]
>


---------------------------------------------------------------------
To unsubscribe, e-mail: [hidden email]
For additional commands, e-mail: [hidden email]

Reply | Threaded
Open this post in threaded view
|

RE: Tomcat discards and reloads the jar files from the webapps folder.

Duca,Cristian
Hello,

I have tried adding the following property: backgroundProcessorDelay="90"
This is an Attribute corresponding to the Engine

I have added he setting as it follows in server.xml
        <Engine name="stp" defaultHost="localhost" jvmRoute="${jvm.route}" backgroundProcessorDelay="90">

After the jvm has been initialized there was no impact in the jar discard/reload, tomcat9 does the same thing.

I can tell you that looking in process explorer I can see that the jar files from the webapps folder are not being discarded on tomcat7.

Note that: we have almost the same configuration(server.xml, context.xml, web.xml -> because these files are templated) coming from tomcat7 to tomcat9.

Thank you,
Cristian Duca.

-----Original Message-----
From: Mark Thomas <[hidden email]>
Sent: Wednesday, 9 October, 2019 14:47
To: [hidden email]
Subject: Re: Tomcat discards and reloads the jar files from the webapps folder.

On 09/10/2019 11:43, Duca,Cristian wrote:
> Hello,
>
> The web application is trying to load specific classes from the jar files.

Is this genuine class loading (in which case the response below is
correct) or is the application reading the .class files as if they were resources (in which case a different answer applies)?

> The main idea is that in tomcat7 the jar files were kept in memory and when the web application required a specific class the jvm fetched it from memory.

Not exactly. In Tomcat 7 JAR files are kept open for 90s by default before being closed and re-opened later if necessary.

> With tomcat9 when the web application requires a specific class tomcat 9 will try to load the jar file which contains that class.

Again, not exactly. In Tomcat 9 JAR files references are cleaned up by the background processing thread (that triggers various background tasks). By default this occurs every ~10s.

> I would like to have the same behavior as we did in tomcat7, is this possible?

Yes, but...

You probably only want increase this for a single / all web applications so you should set backgroundProcessorDelay="90" in the appropriate context.xml file. This will increase the time between all Context level background tasks so it will also impact:

- reloading as a result of a modified JAR or class file (this feature is
  disabled by default)

- session expiration

- cleaning of the annotation cache

The impact of these should be minimal but actual impact will depend on the application.


The standard Manager implementation (via the processExpiresFrequency
attribute) only checks session expiration every 6 calls to backgroundProcess(). We could add a similar option to StandardRoot that manages resources so that JAR were files open longer by default.

Mark



>
> Thank you,
> Cristian Duca.
> -----Original Message-----
> From: Mark Thomas <[hidden email]>
> Sent: Wednesday, 9 October, 2019 13:39
> To: [hidden email]
> Subject: Re: Tomcat discards and reloads the jar files from the webapps folder.
>
> On 09/10/2019 11:36, Duca,Cristian wrote:
>> Hello,
>>
>> We upgraded our tomcat from 7 to 9 and we observed the following:
>>
>>   *   In tomcat9 the jar files from the webapps folder are discarded and reloaded -> this creates extra input/output operations which increase our CPU Usage.
>>   *   In tomcat7 the jar files were kept loaded in memory and were not discarded.
>>
>> I have tried adding the periodicEventDelay set to 0 or a negative value, but we have the same behavior.
>>
>> Can you please guide me what I can do to have the same behavior as we did with tomcat7.
>
> That depends what resources the web application is attempting to load from the JAR files.
>
> Mark
>
> ---------------------------------------------------------------------
> To unsubscribe, e-mail: [hidden email]
> For additional commands, e-mail: [hidden email]
>
>
>
> CONFIDENTIALITY NOTICE This message and any included attachments are from Cerner Corporation and are intended only for the addressee. The information contained in this message is confidential and may constitute inside or non-public information under international, federal, or state securities laws. Unauthorized forwarding, printing, copying, distribution, or use of such information is strictly prohibited and may be unlawful. If you are not the addressee, please promptly delete this message and notify the sender of the delivery error by e-mail or you may call Cerner's corporate offices in Kansas City, Missouri, U.S.A at (+1) (816)221-1024.
>
> ---------------------------------------------------------------------
> To unsubscribe, e-mail: [hidden email]
> For additional commands, e-mail: [hidden email]
>


---------------------------------------------------------------------
To unsubscribe, e-mail: [hidden email]
For additional commands, e-mail: [hidden email]


---------------------------------------------------------------------
To unsubscribe, e-mail: [hidden email]
For additional commands, e-mail: [hidden email]
Reply | Threaded
Open this post in threaded view
|

Re: Tomcat discards and reloads the jar files from the webapps folder.

markt
On 09/10/2019 13:04, Duca,Cristian wrote:

> Hello,
>
> I have tried adding the following property: backgroundProcessorDelay="90"
> This is an Attribute corresponding to the Engine
>
> I have added he setting as it follows in server.xml
> <Engine name="stp" defaultHost="localhost" jvmRoute="${jvm.route}" backgroundProcessorDelay="90">
>
> After the jvm has been initialized there was no impact in the jar discard/reload, tomcat9 does the same thing.
>
> I can tell you that looking in process explorer I can see that the jar files from the webapps folder are not being discarded on tomcat7.
>
> Note that: we have almost the same configuration(server.xml, context.xml, web.xml -> because these files are templated) coming from tomcat7 to tomcat9.

I'll ask again. Is this genuine class loading or is it something else?

Mark

>
> Thank you,
> Cristian Duca.
>
> -----Original Message-----
> From: Mark Thomas <[hidden email]>
> Sent: Wednesday, 9 October, 2019 14:47
> To: [hidden email]
> Subject: Re: Tomcat discards and reloads the jar files from the webapps folder.
>
> On 09/10/2019 11:43, Duca,Cristian wrote:
>> Hello,
>>
>> The web application is trying to load specific classes from the jar files.
>
> Is this genuine class loading (in which case the response below is
> correct) or is the application reading the .class files as if they were resources (in which case a different answer applies)?
>
>> The main idea is that in tomcat7 the jar files were kept in memory and when the web application required a specific class the jvm fetched it from memory.
>
> Not exactly. In Tomcat 7 JAR files are kept open for 90s by default before being closed and re-opened later if necessary.
>
>> With tomcat9 when the web application requires a specific class tomcat 9 will try to load the jar file which contains that class.
>
> Again, not exactly. In Tomcat 9 JAR files references are cleaned up by the background processing thread (that triggers various background tasks). By default this occurs every ~10s.
>
>> I would like to have the same behavior as we did in tomcat7, is this possible?
>
> Yes, but...
>
> You probably only want increase this for a single / all web applications so you should set backgroundProcessorDelay="90" in the appropriate context.xml file. This will increase the time between all Context level background tasks so it will also impact:
>
> - reloading as a result of a modified JAR or class file (this feature is
>   disabled by default)
>
> - session expiration
>
> - cleaning of the annotation cache
>
> The impact of these should be minimal but actual impact will depend on the application.
>
>
> The standard Manager implementation (via the processExpiresFrequency
> attribute) only checks session expiration every 6 calls to backgroundProcess(). We could add a similar option to StandardRoot that manages resources so that JAR were files open longer by default.
>
> Mark
>
>
>
>>
>> Thank you,
>> Cristian Duca.
>> -----Original Message-----
>> From: Mark Thomas <[hidden email]>
>> Sent: Wednesday, 9 October, 2019 13:39
>> To: [hidden email]
>> Subject: Re: Tomcat discards and reloads the jar files from the webapps folder.
>>
>> On 09/10/2019 11:36, Duca,Cristian wrote:
>>> Hello,
>>>
>>> We upgraded our tomcat from 7 to 9 and we observed the following:
>>>
>>>   *   In tomcat9 the jar files from the webapps folder are discarded and reloaded -> this creates extra input/output operations which increase our CPU Usage.
>>>   *   In tomcat7 the jar files were kept loaded in memory and were not discarded.
>>>
>>> I have tried adding the periodicEventDelay set to 0 or a negative value, but we have the same behavior.
>>>
>>> Can you please guide me what I can do to have the same behavior as we did with tomcat7.
>>
>> That depends what resources the web application is attempting to load from the JAR files.
>>
>> Mark
>>
>> ---------------------------------------------------------------------
>> To unsubscribe, e-mail: [hidden email]
>> For additional commands, e-mail: [hidden email]
>>
>>
>>
>> CONFIDENTIALITY NOTICE This message and any included attachments are from Cerner Corporation and are intended only for the addressee. The information contained in this message is confidential and may constitute inside or non-public information under international, federal, or state securities laws. Unauthorized forwarding, printing, copying, distribution, or use of such information is strictly prohibited and may be unlawful. If you are not the addressee, please promptly delete this message and notify the sender of the delivery error by e-mail or you may call Cerner's corporate offices in Kansas City, Missouri, U.S.A at (+1) (816)221-1024.
>>
>> ---------------------------------------------------------------------
>> To unsubscribe, e-mail: [hidden email]
>> For additional commands, e-mail: [hidden email]
>>
>
>
> ---------------------------------------------------------------------
> To unsubscribe, e-mail: [hidden email]
> For additional commands, e-mail: [hidden email]
>
>
> ---------------------------------------------------------------------
> To unsubscribe, e-mail: [hidden email]
> For additional commands, e-mail: [hidden email]
>


---------------------------------------------------------------------
To unsubscribe, e-mail: [hidden email]
For additional commands, e-mail: [hidden email]

Reply | Threaded
Open this post in threaded view
|

RE: Tomcat discards and reloads the jar files from the webapps folder.

Duca,Cristian
Yes, it is the default loader.

-----Original Message-----
From: Mark Thomas <[hidden email]>
Sent: Wednesday, 9 October, 2019 15:57
To: [hidden email]
Subject: Re: Tomcat discards and reloads the jar files from the webapps folder.

On 09/10/2019 13:04, Duca,Cristian wrote:

> Hello,
>
> I have tried adding the following property: backgroundProcessorDelay="90"
> This is an Attribute corresponding to the Engine
>
> I have added he setting as it follows in server.xml
> <Engine name="stp" defaultHost="localhost" jvmRoute="${jvm.route}" backgroundProcessorDelay="90">
>
> After the jvm has been initialized there was no impact in the jar discard/reload, tomcat9 does the same thing.
>
> I can tell you that looking in process explorer I can see that the jar files from the webapps folder are not being discarded on tomcat7.
>
> Note that: we have almost the same configuration(server.xml, context.xml, web.xml -> because these files are templated) coming from tomcat7 to tomcat9.

I'll ask again. Is this genuine class loading or is it something else?

Mark

>
> Thank you,
> Cristian Duca.
>
> -----Original Message-----
> From: Mark Thomas <[hidden email]>
> Sent: Wednesday, 9 October, 2019 14:47
> To: [hidden email]
> Subject: Re: Tomcat discards and reloads the jar files from the webapps folder.
>
> On 09/10/2019 11:43, Duca,Cristian wrote:
>> Hello,
>>
>> The web application is trying to load specific classes from the jar files.
>
> Is this genuine class loading (in which case the response below is
> correct) or is the application reading the .class files as if they were resources (in which case a different answer applies)?
>
>> The main idea is that in tomcat7 the jar files were kept in memory and when the web application required a specific class the jvm fetched it from memory.
>
> Not exactly. In Tomcat 7 JAR files are kept open for 90s by default before being closed and re-opened later if necessary.
>
>> With tomcat9 when the web application requires a specific class tomcat 9 will try to load the jar file which contains that class.
>
> Again, not exactly. In Tomcat 9 JAR files references are cleaned up by the background processing thread (that triggers various background tasks). By default this occurs every ~10s.
>
>> I would like to have the same behavior as we did in tomcat7, is this possible?
>
> Yes, but...
>
> You probably only want increase this for a single / all web applications so you should set backgroundProcessorDelay="90" in the appropriate context.xml file. This will increase the time between all Context level background tasks so it will also impact:
>
> - reloading as a result of a modified JAR or class file (this feature is
>   disabled by default)
>
> - session expiration
>
> - cleaning of the annotation cache
>
> The impact of these should be minimal but actual impact will depend on the application.
>
>
> The standard Manager implementation (via the processExpiresFrequency
> attribute) only checks session expiration every 6 calls to backgroundProcess(). We could add a similar option to StandardRoot that manages resources so that JAR were files open longer by default.
>
> Mark
>
>
>
>>
>> Thank you,
>> Cristian Duca.
>> -----Original Message-----
>> From: Mark Thomas <[hidden email]>
>> Sent: Wednesday, 9 October, 2019 13:39
>> To: [hidden email]
>> Subject: Re: Tomcat discards and reloads the jar files from the webapps folder.
>>
>> On 09/10/2019 11:36, Duca,Cristian wrote:
>>> Hello,
>>>
>>> We upgraded our tomcat from 7 to 9 and we observed the following:
>>>
>>>   *   In tomcat9 the jar files from the webapps folder are discarded and reloaded -> this creates extra input/output operations which increase our CPU Usage.
>>>   *   In tomcat7 the jar files were kept loaded in memory and were not discarded.
>>>
>>> I have tried adding the periodicEventDelay set to 0 or a negative value, but we have the same behavior.
>>>
>>> Can you please guide me what I can do to have the same behavior as we did with tomcat7.
>>
>> That depends what resources the web application is attempting to load from the JAR files.
>>
>> Mark
>>
>> ---------------------------------------------------------------------
>> To unsubscribe, e-mail: [hidden email]
>> For additional commands, e-mail: [hidden email]
>>
>>
>>
>> CONFIDENTIALITY NOTICE This message and any included attachments are from Cerner Corporation and are intended only for the addressee. The information contained in this message is confidential and may constitute inside or non-public information under international, federal, or state securities laws. Unauthorized forwarding, printing, copying, distribution, or use of such information is strictly prohibited and may be unlawful. If you are not the addressee, please promptly delete this message and notify the sender of the delivery error by e-mail or you may call Cerner's corporate offices in Kansas City, Missouri, U.S.A at (+1) (816)221-1024.
>>
>> ---------------------------------------------------------------------
>> To unsubscribe, e-mail: [hidden email]
>> For additional commands, e-mail: [hidden email]
>>
>
>
> ---------------------------------------------------------------------
> To unsubscribe, e-mail: [hidden email]
> For additional commands, e-mail: [hidden email]
>
>
> ---------------------------------------------------------------------
> To unsubscribe, e-mail: [hidden email]
> For additional commands, e-mail: [hidden email]
>


---------------------------------------------------------------------
To unsubscribe, e-mail: [hidden email]
For additional commands, e-mail: [hidden email]


---------------------------------------------------------------------
To unsubscribe, e-mail: [hidden email]
For additional commands, e-mail: [hidden email]