JVM入門 -メモリ管理編-

関ジャバ'19 7月度 - connpass https://kanjava.connpass.com/event/134133/
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1. JVMೖ໳
 -ϝϞϦ؅ཧฤ- Abe Asami
2. ࣗݾ঺հ "CF
   "TBNJ
   l͖ͷࢠ
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 େࡕͷϑϦʔϥϯεϓϩάϥϚ IUUQOPDPOPOFU !BBUI +BWB,PUMJO4DBMBͳͲͳͲ
3. ࠷ۙ΍͍ͬͯΔ͜ͱ https://www.geekhub.jp/
 ΤϯδχΞಛԽ߹ಉઆ໌ձΠϕϯτɻ࣍ճ 9/14(౔) ։࠵༧ఆ ʮJava11ʹΑΔ
 WebΞϓϦέʔγϣϯ։ൃͰֶͿ
 Javaϓϩάϥϛϯάೖ໳ʯൢചத https://www.udemy.com/java11-springbootweb-java/
4. ͜ͷςʔϚΛબΜͩཧ༝ • ਖ਼௚JVMͷ͜ͱ͸งғؾͰ͔͠ཧղ͍ͯ͠ͳ ͍ͨΊɺษڧ͔͔ͨͬͨ͠Β • ӡ༻ϑΣʔζʹܞΘΔػձ͕গͳ͘ɺύ ϑΥʔϚϯε΍ϝϞϦपΓͷτϥϒϧૺ۰ ܦݧ͕͋·Γͳ͍ɾɾɾ • ࠓ೔͸ϝϞϦ؅ཧͷ࿩͚ͩͰ͢
5. ͦ΋ͦ΋JVMͱ͸
6. Java VM (JavaԾ૝Ϛγϯ) • JavaόΠτίʔυΛ࣮ߦ͢ΔͨΊͷԾ૝؀ڥ • OSґଘΛٵऩͯ͘͠Ε͍ͯΔ
7. JVMʹ͸छྨ͕͋Δ • HotSpot VM, IBM JVM, JRockit, ͳͲͳͲ
8. ࠓճ͸HotSpot VMͷ࿩ • Oracle͕ఏڙ͍ͯ͠ΔJVM
9. ͋ͱࠓճ͸Java8ͷ࿩Ͱ͢ • ͜ͷ͋ͱͷݕূͰ࢖ͬͨͷ͕Java8
10. JVMͷ࢓૊Έ (ΊͬͪΌͬ͘͟Γ)
11. ϝϞϦߏ଄
23. ࣮ࡍͷϓϩάϥϜͰ GCͷঢ়گΛղੳͯ͠ΈΔ
24. GCϩά • GCͷॲཧ࣌ؒ΍લޙͷϝϞϦ࢖༻ྔͳͲͷϩ ά
25. GCViewer • GCϩάͷϏϡʔΞʔ • https://github.com/chewiebug/GCViewer • 2019/07/18 ݱࡏɺJDK11ະରԠ
26. ͱΓ͋͑ͣɺ ͳΜ͔͠Βಈ͔ͯ͠ GCϩάΛग़ͯ͠ΈΔ
27. ࢀর͕࢒Βͳ͍ΠϯελϯεΛ
 ͻͨ͢Βੜ੒
28. ࣮ߦ java -Xloggc:gc.log -XX:+PrintGCDetails -XX:+PrintGCDateStamps Main GCϩάग़ྗͷͨΊͷΦϓγϣϯ (※ඪ४ग़ྗʹग़͚ͩ͢Ͱ͋Ε͹ 
 -verbose:gc ͚͚ͩͭΕ͹OK)
29. ग़ྗ͞Εͨϩά
30. GCViewerͰ։͍ͯΈΔ
31. ΦϒδΣΫτ͸·ͣYoungྖҬʹ࡞ΒΕɺ
 ੜ੒͔Β͕࣌ؒܦͭͱOldྖҬʹҠಈ͢Δ
32. ࠓճ͸OldྖҬ΁ͷҠಈ͕ൃੜ͠ͳ͍ͨΊ
 ώʔϓશମͷ࢖༻ྔ ≒ YoungྖҬͷώʔϓ࢖༻ྔ
33. GC࣌ʹͪΌΜͱϝϞϦ͕ղ์͞Ε͍ͯΔ
34. ϚΠφʔGCɾɾɾYoungྖҬͷΈ͕ର৅ YoungྖҬ͕
 ͍ͬͺ͍ʹͳͬͨ
 λΠϛϯάͰ
 ϚΠφʔGC͕
 ࣮ߦ͞Ε͍ͯΔ
35. ΋͏1ύλʔϯ
 ࢼͯ͠ΈΔ
36. ࢀর͕࢒ΔΠϯελϯεΛ
 ͻͨ͢Βੜ੒
37. GCϩά
38. ͜Ε΋GCViewerͰ։͍ͯΈΔ
40. Full GC (ϝδϟʔGC)ɾɾɾશώʔϓྖҬ͕ର৅
41. Full GC͸͕͔͔࣌ؒΔ 2019-07-18T07:28:35.759-0900: 53.145: [GC (Allocation Failure) [PSYoungGen: 1153507K->190965K(1768960K)] 1400776K->506242K(2118656K), 0.3026525 secs] [Times: user=2.55 sys=0.14, real=0.31 secs] 2019-07-18T07:28:36.064-0900: 53.450: [Full GC (Ergonomics) [PSYoungGen: 190965K->190932K(1768960K)] [ParOldGe 315276K->290297K(610816K)] 506242K->481229K(2379776K), [Metaspace: 2676K->2676K(1056768K)], 4.7517463 secs] [Times: user=29.92 sys=0.06, real=4.75 secs] ্ͷϚΠφʔGC ɾɾɾ 0.31 secs
 ԼͷFull GC ɾɾɾ 4.75 secs
42. GCத͸ΞϓϦέʔγϣϯ
 εϨου͕ࢭ·Δ Stop the World (STW) ͱݺ͹ΕΔ
43. OutOfMemoryError(OOME) Λൃੜͤͯ͞ΈΔ
44. ώʔϓͷ࠷େαΠζΛมߋ
 ͯ͠ΈΔ % java -Xms600m -Xmx800m -Xloggc:gc.log -XX:+PrintGCDetails -XX: +PrintGCDateStamps Main -Xms ɾɾɾώʔϓͷॳظαΠζ
 -Xmx ɾɾɾώʔϓͷ࠷େαΠζ
45. ແࣄ(?) OOMEൃੜ
46. GCϩά
47. ΋͏ͪΐͬͱৄ͘͠ղੳΛ
 ͯ͠ΈΔ
48. ώʔϓμϯϓ • ಛఆͷ࣌ࠁʹώʔϓ಺ʹؚ·ΕΔ͢΂ͯͷΦϒ δΣΫτͷεφοϓγϣοτ
49. OOMEൃੜ࣌ʹώʔϓμϯϓΛ ग़ྗͤͯ͞ΈΔ java -Xms600m -Xmx800m -Xloggc:gc.log -XX:+PrintGCDetails -XX: +PrintGCDateStamps -XX:+HeapDumpOnOutOfMemoryError Main -XX:+HeapDumpOnOutOfMemoryError
 ɾɾɾ OOMEൃੜ࣌ʹώʔϓμϯϓΛग़ྗ
50. The Eclipse Memory Analyzer • Eclipse Memory Analyzer Open Source Project | The Eclipse Foundation
 https://www.eclipse.org/mat/ • ώʔϓμϯϓΛ͍͍ײ͡ʹදࣔͯ͘͠ΕΔGUI πʔϧ
51. ώʔϓμϯϓΛ։͍ͯΈͨ
54. ·ͱΊ • ͜͏͍ͬͨJVMͷجຊ΍໰୊ൃੜ࣌ͷղੳํ ๏Λ஌͓ͬͯ͘ͱɺ͍͟ͱ͍͏ͱ͖ʹ߄ͯͳ ͯ͘ศར(ଟ෼)
55. ͪͳΈʹJava11ͷσʔλ෼ੳʹ͸
 Java Mission ControlΛ࢖͏ͱ͍͍ͦ͏Ͱ͢ • Java Mission Control 
 https://www.oracle.com/technetwork/jp/ java/javaseproducts/mission-control/ index.html • ༗ঈػೳ͕ͩͬͨɺJava11͔ΒOpenJDKʹ دଃ͞Εͯແঈఏڙͱͳͬͨ
56. ࢀߟʹͨ͠ϖʔδ • OutOfMemoryError ͷௐ΂ํ - Qiita https://qiita.com/opengl-8080/items/ 64152ee9965441f7667b • Java͸ͲͷΑ͏ʹಈ͘ͷ͔ʙਤղͰΘ͔ΔJVMͷ࢓૊Έɿ࿈ࡌʛgihyo.jp … ٕज़ධ࿦ࣾ http://gihyo.jp/dev/serial/01/jvm-arc • ʮϝϞϦʔΛҙࣝͯ͠ΈΑ͏ʯୈ2ճɹGCͷ࢓૊ΈΛཧղ͢Δ | ೔ܦ xTECH ʢΫϩεςοΫʣ https://tech.nikkeibp.co.jp/it/article/COLUMN/ 20060612/240657/?rt=nocnt • ·͡ΊʹJVMνϡʔχϯά: ୈ1ճ ·ͣ͸ݱঢ়֬ೝ https://x1.inkenkun.com/ archives/367
57. ͝ਗ਼ௌ
 ͋Γ͕ͱ͏͍͟͝·ͨ͠