===== [V8] ISSUE: GC (Allocation Failure) in catalina log after upgrading AhsayCBS to version 8   =====

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  Article ID:
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 8034
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  Reviewed:
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 2019-03-20
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  Product Version:
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 AhsayCBS: 8.1.0.0 to 8.x
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 OS: All platforms
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===== Problem Description =====
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After upgrading the AhsayCBS server application to version 8, the following informative message are received in the catalina.out server log file:
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DD-MMM-YYYY hh:mm:ss.xxx+0000: [CMS-concurrent-preclean-start]<br>
DD-MMM-YYYY hh:mm:ss.xxx+0000: [CMS-concurrent-preclean: 0.002/0.002 secs] [Times: user=0.00 sys=0.00, real=0.01 secs]<br>
DD-MMM-YYYY hh:mm:ss.xxx+0000: [<font color=red>GC (Allocation Failure)</font> DD-MMM-YYYY hh:mm:ss.xxx+0000: [ParNewDD-MMM-YYYY hh:mm:ss.xxx+0000: [CMS-concurrent-abortable-preclean: 0.038/0.145 secs] [Times: user=0.21 sys=0.01, real=0.14 secs]: 126976K->4096K(126976K), 0.0938717 secs] 543109K->441169K(618432K), 0.0939455 secs] [Times: user=0.12 sys=0.00, real=0.09 secs]<br>
DD-MMM-YYYY hh:mm:ss.xxx0000: [GC (CMS Final Remark) [YG occupancy: 6543 K (126976 K)]DD-MMM-YYYY hh:mm:ss.xxx+0000: [GC (CMS Final Remark) DD-MMM-YYYY hh:mm:ss.xxx+0000: [ParNew: 6543K->3499K(126976K), 0.0162797 secs] 443617K->444720K(619684K), 0.0163264 secs] [Times: user=0.03 sys=0.00, real=0.02 secs]<br>
DD-MMM-YYYY hh:mm:ss.xxx+0000: [Rescan (parallel) , 0.0232216 secs]DD-MMM-YYYY hh:mm:ss.xxx+0000: [weak refs processing, 0.0258297 secs]DD-MMM-YYYY hh:mm:ss.xxx+0000: [class unloading, 0.0080231 secs]DD-MMM-YYYY hh:mm:ss.xxx+0000: [scrub symbol table, 0.0067435 secs]DD-MMM-YYYY hh:mm:ss.xxx+0000: [scrub string table, 0.0010432 secs][1 CMS-remark: 441220K(492708K)] 444720K(619684K), 0.0814779 secs] [Times: user=0.12 sys=0.00, real=0.09 secs]<br>
DD-MMM-YYYY hh:mm:ss.xxx+0000: [CMS-concurrent-sweep-start]<br>
DD-MMM-YYYY hh:mm:ss.xxx+0000: [<font color=red>GC (Allocation Failure)</font> DD-MMM-YYYY hh:mm:ss.xxx+0000: [ParNew: 126379K->4095K(126976K), 0.0755672 secs] 299409K->192823K(619684K), 0.0756426 secs] [Times: user=0.08 sys=0.00, real=0.08 secs]<br>
DD-MMM-YYYY hh:mm:ss.xxx+0000: [CMS-concurrent-sweep: 0.301/0.376 secs] [Times: user=0.66 sys=0.01, real=0.38 secs]<br>
DD-MMM-YYYY hh:mm:ss.xxx+0000: [CMS-concurrent-reset-start]<br>
DD-MMM-YYYY hh:mm:ss.xxx+0000: [CMS-concurrent-reset: 0.001/0.001 secs] [Times: user=0.01 sys=0.00, real=0.00 secs]<br>
DD-MMM-YYYY hh:mm:ss.xxx+0000: [<font color=red>GC (Allocation Failure)</font> DD-MMM-YYYY hh:mm:ss.xxx+0000: [ParNew: 126975K->4096K(126976K), 0.0824005 secs] 248798K->144191K(619684K), 0.0824743 secs] [Times: user=0.09 sys=0.00, real=0.08 secs]
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===== Cause =====
This is an informative message returned by the Tomcat web server (AhsayCBS version 8 is bundled with Tomcat version 8.5.34, whereas AhsayCBS version 7 is bundled with Tomcat version 7.0.81).

===== Resolution =====
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Even though the message say allocation failure, precisely, "GC (Allocation Failure)" means that the Java garbage collector was initiated, ran out of space in the heap, then tried to allocate more memory. &nbsp;The GC (Garbage Collection) process was completed successful.

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Administrator can safely ignore the message (except if you see "java.lang.OutOfMemoryError: Java heap space"), no user interaction is required.
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===== Keywords =====
gc, garbage, collecion, java, heap, memory