{"id":50529,"date":"2019-09-02T06:00:50","date_gmt":"2019-09-02T04:00:50","guid":{"rendered":"http:\/\/smeupnew.it\/magazine\/blog\/thread-dump-situazioni-critiche\/"},"modified":"2021-04-07T10:56:56","modified_gmt":"2021-04-07T08:56:56","slug":"thread-dump-situazioni-critiche","status":"publish","type":"post","link":"https:\/\/www.smeup.com\/magazine\/blog\/thread-dump-situazioni-critiche\/","title":{"rendered":"Thread dump in situazioni critiche &#8211; parte 8"},"content":{"rendered":"<div class=\"fusion-fullwidth fullwidth-box fusion-builder-row-1 fusion-flex-container nonhundred-percent-fullwidth non-hundred-percent-height-scrolling gradient-container-1\" style=\"--awb-border-radius-top-left:0px;--awb-border-radius-top-right:0px;--awb-border-radius-bottom-right:0px;--awb-border-radius-bottom-left:0px;--awb-flex-wrap:wrap;\" ><div class=\"fusion-builder-row fusion-row fusion-flex-align-items-flex-start fusion-flex-content-wrap\" style=\"max-width:1144px;margin-left: calc(-4% \/ 2 );margin-right: calc(-4% \/ 2 );\"><div class=\"fusion-layout-column fusion_builder_column fusion-builder-column-0 fusion_builder_column_1_1 1_1 fusion-flex-column\" style=\"--awb-bg-size:cover;--awb-width-large:100%;--awb-margin-top-large:0px;--awb-spacing-right-large:1.92%;--awb-margin-bottom-large:0px;--awb-spacing-left-large:1.92%;--awb-width-medium:100%;--awb-spacing-right-medium:1.92%;--awb-spacing-left-medium:1.92%;--awb-width-small:100%;--awb-spacing-right-small:1.92%;--awb-spacing-left-small:1.92%;\"><div class=\"fusion-column-wrapper fusion-flex-justify-content-flex-start fusion-content-layout-column\"><div class=\"fusion-text fusion-text-1\"><p>Le scorse puntate:<\/p>\n<ul>\n<li><a href=\"https:\/\/www.smeup.com\/magazine\/blog\/performance-monitoring-tool-parte-1\/\" target=\"_blank\" rel=\"noopener\">Introduzione ai performance monitoring tool \u2013 parte 1<\/a><\/li>\n<li><a href=\"https:\/\/www.smeup.com\/magazine\/blog\/apm-open-source-glowroot\/\" target=\"_blank\" rel=\"noopener\">Esempio di un APM open source per un\u2019app web Java J2EE: Glowroot \u2013 parte 2<\/a><\/li>\n<li><a href=\"https:\/\/www.smeup.com\/magazine\/blog\/glowroot-profilazione-transazioni-web\/\" target=\"_blank\" rel=\"noopener\">Glowroot \u2013 Profilazione e transazioni web \u2013 parte 3<\/a><\/li>\n<li><a href=\"https:\/\/www.smeup.com\/magazine\/blog\/glowroot-slow-traces\/\" target=\"_blank\" rel=\"noopener\">Glowroot Slow traces \u2013 parte 4<\/a><\/li>\n<li><a href=\"https:\/\/www.smeup.com\/magazine\/blog\/monitoring-della-jvm\/\" target=\"_blank\" rel=\"noopener\">Glowroot: monitoring della JVM \u2013 parte 5<\/a><\/li>\n<li><a href=\"https:\/\/www.smeup.com\/magazine\/blog\/heap-dump-situazioni-critiche\/\" target=\"_blank\" rel=\"noopener\">Heap dump in situazioni critiche \u2013 parte 6<\/a><\/li>\n<li><a href=\"https:\/\/www.smeup.com\/magazine\/blog\/memory-leak\/\" target=\"_blank\" rel=\"noopener\">Un caso reale di memory leak \u2013 parte 7<\/a><\/li>\n<\/ul>\n<p><span style=\"font-weight: 400;\">Nei precedenti articoli abbiamo trattato dell\u2019esame dell\u2019heap dump in situazioni critiche. Ora ci concentreremo sull\u2019esame del <\/span><b>thread dump<\/b><span style=\"font-weight: 400;\">, esponendo anche un caso concreto di risoluzione di un problema di performance tramite l\u2019utilizzo di questa tecnica effettuato all\u2019interno del <a href=\"https:\/\/www.smeup.com\/laboratorio-gruppo-smeup\/\" target=\"_blank\" rel=\"noopener\">Laboratorio di smeup<\/a>.<\/span><\/p>\n<h2>Applicazioni multi-thread<\/h2>\n<p><span style=\"font-weight: 400;\">La maggior parte delle applicazioni Java sviluppate oggi giorno coinvolgono <\/span><b>thread<\/b><span style=\"font-weight: 400;\"> (sottoprocessi) multipli.\u00a0<\/span><\/p>\n<p><span style=\"font-weight: 400;\">L\u2019utilizzo di thread multipli permette di parallelizzare le attivit\u00e0 e quindi di aumentare le performance di un sistema. E\u2019 per\u00f2 necessario che il parallelismo sia correttamente gestito perch\u00e9 l\u2019accesso alle risorse comuni (ad esempio dati comuni, periferiche di input\/output, etc\u2026) deve essere coordinato. Ci\u00f2 generalmente avviene ponendo un <\/span><b>lock<\/b><span style=\"font-weight: 400;\"> (blocco) sulla risorsa utilizzata da un thread, assicurando in questo modo che nessun altro thread possa accedervi finch\u00e9 il thread bloccante non abbia concluso l\u2019operazione sulla risorsa e rilasciato il blocco.\u00a0<\/span><\/p>\n<p><span style=\"font-weight: 400;\">Purtroppo il locking delle risorse pu\u00f2 generare alcuni scenari spiacevoli, come ad esempio i <\/span><b>deadlock<\/b><span style=\"font-weight: 400;\"> e i <\/span><b>livelock<\/b><span style=\"font-weight: 400;\">.<\/span><\/p>\n<p><span style=\"font-weight: 400;\">Un <\/span><b>deadlock<\/b><span style=\"font-weight: 400;\"> \u00e8 uno scenario in cui i thread bloccano vicendevolmente le risorse tra loro generando uno stallo.<\/span><\/p>\n<p><span style=\"font-weight: 400;\">Un caso pu\u00f2 essere quello di un thread X che sta usando e quindi bloccando una risorsa A ed \u00e8 in attesa della disponibilit\u00e0 di una risorsa B e di un thread Y che sta usando e quindi bloccando la risorsa B ed \u00e8 in attesa della disponibilit\u00e0 della risorsa A.<\/span><\/p>\n<\/div><\/div><\/div><div class=\"fusion-layout-column fusion_builder_column fusion-builder-column-1 fusion_builder_column_1_2 1_2 fusion-flex-column\" style=\"--awb-bg-size:cover;--awb-width-large:50%;--awb-margin-top-large:20px;--awb-spacing-right-large:3.84%;--awb-margin-bottom-large:20px;--awb-spacing-left-large:3.84%;--awb-width-medium:50%;--awb-order-medium:0;--awb-spacing-right-medium:3.84%;--awb-spacing-left-medium:3.84%;--awb-width-small:100%;--awb-order-small:0;--awb-spacing-right-small:1.92%;--awb-spacing-left-small:1.92%;\"><div class=\"fusion-column-wrapper fusion-column-has-shadow fusion-flex-justify-content-flex-start fusion-content-layout-column\"><div class=\"fusion-image-element \" style=\"--awb-caption-title-font-family:var(--h2_typography-font-family);--awb-caption-title-font-weight:var(--h2_typography-font-weight);--awb-caption-title-font-style:var(--h2_typography-font-style);--awb-caption-title-size:var(--h2_typography-font-size);--awb-caption-title-transform:var(--h2_typography-text-transform);--awb-caption-title-line-height:var(--h2_typography-line-height);--awb-caption-title-letter-spacing:var(--h2_typography-letter-spacing);\"><span class=\" fusion-imageframe imageframe-none imageframe-1 hover-type-none\"><a class=\"fusion-no-lightbox\" href=\"https:\/\/www.smeup.com\/wp-content\/uploads\/2019\/09\/simple-deadlock-1024x1024.png\" target=\"_blank\" aria-label=\"smeup simple deadlock\" rel=\"noopener noreferrer\"><img decoding=\"async\" width=\"300\" height=\"300\" alt=\"smeup simple deadlock\" src=\"https:\/\/www.smeup.com\/magazine\/wp-content\/uploads\/sites\/5\/2019\/09\/simple-deadlock.png\" data-orig-src=\"https:\/\/www.smeup.com\/magazine\/wp-content\/uploads\/sites\/5\/2019\/09\/simple-deadlock.png\" class=\"lazyload img-responsive wp-image-53302\" srcset=\"data:image\/svg+xml,%3Csvg%20xmlns%3D%27http%3A%2F%2Fwww.w3.org%2F2000%2Fsvg%27%20width%3D%27300%27%20height%3D%27300%27%20viewBox%3D%270%200%20300%20300%27%3E%3Crect%20width%3D%27300%27%20height%3D%27300%27%20fill-opacity%3D%220%22%2F%3E%3C%2Fsvg%3E\" data-srcset=\"https:\/\/www.smeup.com\/magazine\/wp-content\/uploads\/sites\/5\/2019\/09\/simple-deadlock-200x200.png 200w, https:\/\/www.smeup.com\/magazine\/wp-content\/uploads\/sites\/5\/2019\/09\/simple-deadlock.png 300w\" data-sizes=\"auto\" data-orig-sizes=\"(max-width: 640px) 100vw, 300px\" \/><\/a><\/span><\/div><\/div><\/div><div class=\"fusion-layout-column fusion_builder_column fusion-builder-column-2 fusion_builder_column_1_2 1_2 fusion-flex-column\" style=\"--awb-bg-size:cover;--awb-width-large:50%;--awb-margin-top-large:20px;--awb-spacing-right-large:3.84%;--awb-margin-bottom-large:20px;--awb-spacing-left-large:3.84%;--awb-width-medium:50%;--awb-order-medium:0;--awb-spacing-right-medium:3.84%;--awb-spacing-left-medium:3.84%;--awb-width-small:100%;--awb-order-small:0;--awb-spacing-right-small:1.92%;--awb-spacing-left-small:1.92%;\"><div class=\"fusion-column-wrapper fusion-column-has-shadow fusion-flex-justify-content-flex-start fusion-content-layout-column\"><div class=\"fusion-image-element \" style=\"--awb-caption-title-font-family:var(--h2_typography-font-family);--awb-caption-title-font-weight:var(--h2_typography-font-weight);--awb-caption-title-font-style:var(--h2_typography-font-style);--awb-caption-title-size:var(--h2_typography-font-size);--awb-caption-title-transform:var(--h2_typography-text-transform);--awb-caption-title-line-height:var(--h2_typography-line-height);--awb-caption-title-letter-spacing:var(--h2_typography-letter-spacing);\"><span class=\" fusion-imageframe imageframe-none imageframe-2 hover-type-none\"><a class=\"fusion-no-lightbox\" href=\"https:\/\/www.smeup.com\/wp-content\/uploads\/2019\/09\/simple-deadlock-01-1-1024x1024.png\" target=\"_blank\" aria-label=\"smeup simple deadlock 1\" rel=\"noopener noreferrer\"><img decoding=\"async\" width=\"300\" height=\"300\" alt=\"smeup simple deadlock 1\" src=\"https:\/\/www.smeup.com\/magazine\/wp-content\/uploads\/sites\/5\/2019\/09\/simple-deadlock-1.png\" data-orig-src=\"https:\/\/www.smeup.com\/magazine\/wp-content\/uploads\/sites\/5\/2019\/09\/simple-deadlock-1.png\" class=\"lazyload img-responsive wp-image-53304\" srcset=\"data:image\/svg+xml,%3Csvg%20xmlns%3D%27http%3A%2F%2Fwww.w3.org%2F2000%2Fsvg%27%20width%3D%27300%27%20height%3D%27300%27%20viewBox%3D%270%200%20300%20300%27%3E%3Crect%20width%3D%27300%27%20height%3D%27300%27%20fill-opacity%3D%220%22%2F%3E%3C%2Fsvg%3E\" data-srcset=\"https:\/\/www.smeup.com\/magazine\/wp-content\/uploads\/sites\/5\/2019\/09\/simple-deadlock-1-200x200.png 200w, https:\/\/www.smeup.com\/magazine\/wp-content\/uploads\/sites\/5\/2019\/09\/simple-deadlock-1.png 300w\" data-sizes=\"auto\" data-orig-sizes=\"(max-width: 640px) 100vw, 300px\" \/><\/a><\/span><\/div><\/div><\/div><div class=\"fusion-layout-column fusion_builder_column fusion-builder-column-3 fusion_builder_column_1_1 1_1 fusion-flex-column\" style=\"--awb-bg-size:cover;--awb-width-large:100%;--awb-margin-top-large:20px;--awb-spacing-right-large:1.92%;--awb-margin-bottom-large:20px;--awb-spacing-left-large:1.92%;--awb-width-medium:100%;--awb-order-medium:0;--awb-spacing-right-medium:1.92%;--awb-spacing-left-medium:1.92%;--awb-width-small:100%;--awb-order-small:0;--awb-spacing-right-small:1.92%;--awb-spacing-left-small:1.92%;\"><div class=\"fusion-column-wrapper fusion-column-has-shadow fusion-flex-justify-content-flex-start fusion-content-layout-column\"><div class=\"fusion-text fusion-text-2\"><p><span style=\"font-weight: 400;\">Il blocco pu\u00f2 capitare anche con pi\u00f9 di due thread coinvolti. Ad esempio quando il thread X sta usando la risorsa A e richiede la C, il thread Y sta usando la B e richiede la A e il thread Z sta usando la C e richiede la risorsa B. Un caso del genere \u00e8 formalmente riconducibile al cosiddetto <\/span><a href=\"https:\/\/it.wikipedia.org\/wiki\/Problema_dei_filosofi_a_cena\" target=\"_blank\" rel=\"noopener noreferrer\"><b>problema dei filosofi a cena<\/b><\/a><span style=\"font-weight: 400;\">, la cui formulazione originale definiva 5 thread (i filosofi) e 5 risorse (le forchette per mangiare).<\/span><\/p>\n<\/div><\/div><\/div><div class=\"fusion-layout-column fusion_builder_column fusion-builder-column-4 fusion_builder_column_1_2 1_2 fusion-flex-column\" style=\"--awb-bg-size:cover;--awb-width-large:50%;--awb-margin-top-large:20px;--awb-spacing-right-large:3.84%;--awb-margin-bottom-large:20px;--awb-spacing-left-large:3.84%;--awb-width-medium:50%;--awb-order-medium:0;--awb-spacing-right-medium:3.84%;--awb-spacing-left-medium:3.84%;--awb-width-small:100%;--awb-order-small:0;--awb-spacing-right-small:1.92%;--awb-spacing-left-small:1.92%;\"><div class=\"fusion-column-wrapper fusion-column-has-shadow fusion-flex-justify-content-flex-start fusion-content-layout-column\"><div class=\"fusion-image-element \" style=\"--awb-caption-title-font-family:var(--h2_typography-font-family);--awb-caption-title-font-weight:var(--h2_typography-font-weight);--awb-caption-title-font-style:var(--h2_typography-font-style);--awb-caption-title-size:var(--h2_typography-font-size);--awb-caption-title-transform:var(--h2_typography-text-transform);--awb-caption-title-line-height:var(--h2_typography-line-height);--awb-caption-title-letter-spacing:var(--h2_typography-letter-spacing);\"><span class=\" fusion-imageframe imageframe-none imageframe-3 hover-type-none\"><a class=\"fusion-no-lightbox\" href=\"https:\/\/www.smeup.com\/wp-content\/uploads\/2019\/09\/problema-filosofi-cena-02-1024x1024.png\" target=\"_blank\" aria-label=\"smeup problema filosofi cena\" rel=\"noopener noreferrer\"><img decoding=\"async\" width=\"300\" height=\"300\" alt=\"smeup problema filosofi cena\" src=\"https:\/\/www.smeup.com\/magazine\/wp-content\/uploads\/sites\/5\/2019\/09\/problema-filosofi-cena.png\" data-orig-src=\"https:\/\/www.smeup.com\/magazine\/wp-content\/uploads\/sites\/5\/2019\/09\/problema-filosofi-cena.png\" class=\"lazyload img-responsive wp-image-53306\" srcset=\"data:image\/svg+xml,%3Csvg%20xmlns%3D%27http%3A%2F%2Fwww.w3.org%2F2000%2Fsvg%27%20width%3D%27300%27%20height%3D%27300%27%20viewBox%3D%270%200%20300%20300%27%3E%3Crect%20width%3D%27300%27%20height%3D%27300%27%20fill-opacity%3D%220%22%2F%3E%3C%2Fsvg%3E\" data-srcset=\"https:\/\/www.smeup.com\/magazine\/wp-content\/uploads\/sites\/5\/2019\/09\/problema-filosofi-cena-200x200.png 200w, https:\/\/www.smeup.com\/magazine\/wp-content\/uploads\/sites\/5\/2019\/09\/problema-filosofi-cena.png 300w\" data-sizes=\"auto\" data-orig-sizes=\"(max-width: 640px) 100vw, 300px\" \/><\/a><\/span><\/div><\/div><\/div><div class=\"fusion-layout-column fusion_builder_column fusion-builder-column-5 fusion_builder_column_1_2 1_2 fusion-flex-column\" style=\"--awb-bg-size:cover;--awb-width-large:50%;--awb-margin-top-large:20px;--awb-spacing-right-large:3.84%;--awb-margin-bottom-large:20px;--awb-spacing-left-large:3.84%;--awb-width-medium:50%;--awb-order-medium:0;--awb-spacing-right-medium:3.84%;--awb-spacing-left-medium:3.84%;--awb-width-small:100%;--awb-order-small:0;--awb-spacing-right-small:1.92%;--awb-spacing-left-small:1.92%;\"><div class=\"fusion-column-wrapper fusion-column-has-shadow fusion-flex-justify-content-flex-start fusion-content-layout-column\"><div class=\"fusion-image-element \" style=\"--awb-caption-title-font-family:var(--h2_typography-font-family);--awb-caption-title-font-weight:var(--h2_typography-font-weight);--awb-caption-title-font-style:var(--h2_typography-font-style);--awb-caption-title-size:var(--h2_typography-font-size);--awb-caption-title-transform:var(--h2_typography-text-transform);--awb-caption-title-line-height:var(--h2_typography-line-height);--awb-caption-title-letter-spacing:var(--h2_typography-letter-spacing);\"><span class=\" fusion-imageframe imageframe-none imageframe-4 hover-type-none\"><a class=\"fusion-no-lightbox\" href=\"https:\/\/www.smeup.com\/wp-content\/uploads\/2019\/09\/problema-filosofi-cena-1024x1024.png\" target=\"_blank\" aria-label=\"smeup problema filosofi cena 1\" rel=\"noopener noreferrer\"><img decoding=\"async\" width=\"300\" height=\"300\" alt=\"smeup problema filosofi cena 1\" src=\"https:\/\/www.smeup.com\/magazine\/wp-content\/uploads\/sites\/5\/2019\/09\/problema-filosofi-cena-1.png\" data-orig-src=\"https:\/\/www.smeup.com\/magazine\/wp-content\/uploads\/sites\/5\/2019\/09\/problema-filosofi-cena-1.png\" class=\"lazyload img-responsive wp-image-53308\" srcset=\"data:image\/svg+xml,%3Csvg%20xmlns%3D%27http%3A%2F%2Fwww.w3.org%2F2000%2Fsvg%27%20width%3D%27300%27%20height%3D%27300%27%20viewBox%3D%270%200%20300%20300%27%3E%3Crect%20width%3D%27300%27%20height%3D%27300%27%20fill-opacity%3D%220%22%2F%3E%3C%2Fsvg%3E\" data-srcset=\"https:\/\/www.smeup.com\/magazine\/wp-content\/uploads\/sites\/5\/2019\/09\/problema-filosofi-cena-1-200x200.png 200w, https:\/\/www.smeup.com\/magazine\/wp-content\/uploads\/sites\/5\/2019\/09\/problema-filosofi-cena-1.png 300w\" data-sizes=\"auto\" data-orig-sizes=\"(max-width: 640px) 100vw, 300px\" \/><\/a><\/span><\/div><\/div><\/div><div class=\"fusion-layout-column fusion_builder_column fusion-builder-column-6 fusion_builder_column_1_1 1_1 fusion-flex-column\" style=\"--awb-bg-size:cover;--awb-width-large:100%;--awb-margin-top-large:20px;--awb-spacing-right-large:1.92%;--awb-margin-bottom-large:20px;--awb-spacing-left-large:1.92%;--awb-width-medium:100%;--awb-order-medium:0;--awb-spacing-right-medium:1.92%;--awb-spacing-left-medium:1.92%;--awb-width-small:100%;--awb-order-small:0;--awb-spacing-right-small:1.92%;--awb-spacing-left-small:1.92%;\"><div class=\"fusion-column-wrapper fusion-column-has-shadow fusion-flex-justify-content-flex-start fusion-content-layout-column\"><div class=\"fusion-text fusion-text-3\"><p>Un <strong>livelock<\/strong> \u00e8 uno scenario in cui un thread X esegue un&#8217;azione A la quale comporta che il thread Y esegua un&#8217;azione B la quale comporta che il thread X esegua l&#8217;azione A. Questa situazione genera un ciclo infinito. Come nel caso dei deadlock i livelock generano uno stallo nell&#8217;applicazione, la quale non progredisce, ma a differenza dei deadlock i thread coinvolti non sono bloccati, ma lavorano senza fine.<\/p>\n<\/div><\/div><\/div><div class=\"fusion-layout-column fusion_builder_column fusion-builder-column-7 fusion_builder_column_1_3 1_3 fusion-flex-column\" style=\"--awb-bg-size:cover;--awb-width-large:33.333333333333%;--awb-margin-top-large:20px;--awb-spacing-right-large:5.76%;--awb-margin-bottom-large:20px;--awb-spacing-left-large:5.76%;--awb-width-medium:33.333333333333%;--awb-order-medium:0;--awb-spacing-right-medium:5.76%;--awb-spacing-left-medium:5.76%;--awb-width-small:100%;--awb-order-small:0;--awb-spacing-right-small:1.92%;--awb-spacing-left-small:1.92%;\"><div class=\"fusion-column-wrapper fusion-column-has-shadow fusion-flex-justify-content-flex-start fusion-content-layout-column\"><div class=\"fusion-image-element \" style=\"--awb-caption-title-font-family:var(--h2_typography-font-family);--awb-caption-title-font-weight:var(--h2_typography-font-weight);--awb-caption-title-font-style:var(--h2_typography-font-style);--awb-caption-title-size:var(--h2_typography-font-size);--awb-caption-title-transform:var(--h2_typography-text-transform);--awb-caption-title-line-height:var(--h2_typography-line-height);--awb-caption-title-letter-spacing:var(--h2_typography-letter-spacing);\"><span class=\" fusion-imageframe imageframe-none imageframe-5 hover-type-none\"><img decoding=\"async\" width=\"1024\" height=\"733\" alt=\"smeup livelock\" title=\"smeup livelock\" src=\"https:\/\/www.smeup.com\/magazine\/wp-content\/uploads\/sites\/5\/2019\/09\/livelock.jpg\" data-orig-src=\"https:\/\/www.smeup.com\/magazine\/wp-content\/uploads\/sites\/5\/2019\/09\/livelock.jpg\" class=\"lazyload img-responsive wp-image-53310\" srcset=\"data:image\/svg+xml,%3Csvg%20xmlns%3D%27http%3A%2F%2Fwww.w3.org%2F2000%2Fsvg%27%20width%3D%271024%27%20height%3D%27733%27%20viewBox%3D%270%200%201024%20733%27%3E%3Crect%20width%3D%271024%27%20height%3D%27733%27%20fill-opacity%3D%220%22%2F%3E%3C%2Fsvg%3E\" data-srcset=\"https:\/\/www.smeup.com\/magazine\/wp-content\/uploads\/sites\/5\/2019\/09\/livelock-200x143.jpg 200w, https:\/\/www.smeup.com\/magazine\/wp-content\/uploads\/sites\/5\/2019\/09\/livelock-400x286.jpg 400w, https:\/\/www.smeup.com\/magazine\/wp-content\/uploads\/sites\/5\/2019\/09\/livelock-600x429.jpg 600w, https:\/\/www.smeup.com\/magazine\/wp-content\/uploads\/sites\/5\/2019\/09\/livelock-800x573.jpg 800w, https:\/\/www.smeup.com\/magazine\/wp-content\/uploads\/sites\/5\/2019\/09\/livelock.jpg 1024w\" data-sizes=\"auto\" data-orig-sizes=\"(max-width: 640px) 100vw, 400px\" \/><\/span><\/div><\/div><\/div><div class=\"fusion-layout-column fusion_builder_column fusion-builder-column-8 fusion_builder_column_2_3 2_3 fusion-flex-column\" style=\"--awb-bg-size:cover;--awb-width-large:66.666666666667%;--awb-margin-top-large:20px;--awb-spacing-right-large:2.88%;--awb-margin-bottom-large:20px;--awb-spacing-left-large:2.88%;--awb-width-medium:66.666666666667%;--awb-order-medium:0;--awb-spacing-right-medium:2.88%;--awb-spacing-left-medium:2.88%;--awb-width-small:100%;--awb-order-small:0;--awb-spacing-right-small:1.92%;--awb-spacing-left-small:1.92%;\"><div class=\"fusion-column-wrapper fusion-column-has-shadow fusion-flex-justify-content-flex-start fusion-content-layout-column\"><\/div><\/div><div class=\"fusion-layout-column fusion_builder_column fusion-builder-column-9 fusion_builder_column_1_1 1_1 fusion-flex-column\" style=\"--awb-bg-size:cover;--awb-width-large:100%;--awb-margin-top-large:20px;--awb-spacing-right-large:1.92%;--awb-margin-bottom-large:20px;--awb-spacing-left-large:1.92%;--awb-width-medium:100%;--awb-order-medium:0;--awb-spacing-right-medium:1.92%;--awb-spacing-left-medium:1.92%;--awb-width-small:100%;--awb-order-small:0;--awb-spacing-right-small:1.92%;--awb-spacing-left-small:1.92%;\"><div class=\"fusion-column-wrapper fusion-column-has-shadow fusion-flex-justify-content-flex-start fusion-content-layout-column\"><div class=\"fusion-text fusion-text-4\"><p><strong>Un\u2019applicazione web Java EE<\/strong>, quale ad esempio Web.UP, \u00e8 un\u2019applicazione multi-thread. Essa viene infatti rilasciata su un <strong>application server<\/strong>. L\u2019application server \u00e8 un software che fornisce l\u2019infrastruttura e le funzionalit\u00e0 di supporto per l\u2019esecuzione di applicazioni in contesto distribuito. Al suo interno vengono gestiti numerosi thread, di controllo, di amministrazione e di gestione delle richieste e delle risposte http da e verso i client delle applicazioni web su di esso rilasciate (ad esempio i browser degli utenti).<\/p>\n<p>L\u2019application server consigliato per distribuire Web.UP \u00e8 <a href=\"https:\/\/www.payara.fish\" target=\"_blank\" rel=\"noopener\">Payara<\/a>, un application server open source derivato da <a href=\"https:\/\/en.wikipedia.org\/wiki\/GlassFish\" target=\"_blank\" rel=\"noopener\">Glassfish<\/a>.\u00a0Al suo interno gestisce un<strong> pool<\/strong> (insieme) di thread http, deputati all\u2019esecuzione concorrente del codice dell\u2019applicazione web.<\/p>\n<p><strong>Chiara Zambelli<br \/>\n<\/strong><em>Responsabile CI\/CD &#8211; smeup<br \/>\n<\/em><a href=\"https:\/\/it.linkedin.com\/in\/chiara-zambelli\" target=\"_blank\" rel=\"noopener\">My LinkedIn Profile<\/a><\/p>\n<\/div><\/div><\/div><\/div><\/div>\n","protected":false},"excerpt":{"rendered":"<p>Ci concentreremo sull\u2019esame del thread dump, esponendo anche un caso concreto di risoluzione di un problema di performance tramite l\u2019utilizzo di questa tecnica effettuato all\u2019interno del Laboratorio di Sme.UP.<\/p>\n","protected":false},"author":1,"featured_media":53299,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"footnotes":""},"categories":[7144],"tags":[6377,6378,6312,6380,6381,6382,6316,4431],"class_list":["post-50529","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-erp","tag-applicazioni-multi-thread","tag-deadlock","tag-heap-dump","tag-java-ee","tag-payara","tag-thread","tag-thread-dump","tag-web-up"],"acf":[],"yoast_head":"<!-- This site is optimized with the Yoast SEO plugin v27.6 - https:\/\/yoast.com\/product\/yoast-seo-wordpress\/ -->\n<title>Esame del thread dump in situazioni critiche e risoluzione problemi -parte 8<\/title>\n<meta name=\"description\" content=\"Ci concentreremo sull\u2019esame del thread dump, esponendo un caso di risoluzione di un problema di performance effettuato all\u2019interno del Laboratorio di smeup.\" \/>\n<meta name=\"robots\" content=\"index, follow, max-snippet:-1, max-image-preview:large, max-video-preview:-1\" \/>\n<link rel=\"canonical\" href=\"https:\/\/www.smeup.com\/magazine\/blog\/thread-dump-situazioni-critiche\/\" \/>\n<meta property=\"og:locale\" content=\"it_IT\" \/>\n<meta property=\"og:type\" content=\"article\" \/>\n<meta property=\"og:title\" content=\"Esame del thread dump in situazioni critiche e risoluzione problemi -parte 8\" \/>\n<meta property=\"og:description\" content=\"Ci concentreremo sull\u2019esame del thread dump, esponendo un caso di risoluzione di un problema di performance effettuato all\u2019interno del Laboratorio di smeup.\" \/>\n<meta property=\"og:url\" content=\"https:\/\/www.smeup.com\/magazine\/blog\/thread-dump-situazioni-critiche\/\" \/>\n<meta property=\"og:site_name\" content=\"Magazine\" \/>\n<meta property=\"article:published_time\" content=\"2019-09-02T04:00:50+00:00\" \/>\n<meta property=\"article:modified_time\" content=\"2021-04-07T08:56:56+00:00\" \/>\n<meta property=\"og:image\" content=\"https:\/\/www.smeup.com\/magazine\/wp-content\/uploads\/sites\/5\/2019\/09\/thread-dump.jpg\" \/>\n\t<meta property=\"og:image:width\" content=\"1600\" \/>\n\t<meta property=\"og:image:height\" content=\"1068\" \/>\n\t<meta property=\"og:image:type\" content=\"image\/jpeg\" \/>\n<meta name=\"author\" content=\"smeup\" \/>\n<meta name=\"twitter:card\" content=\"summary_large_image\" \/>\n<meta name=\"twitter:label1\" content=\"Scritto da\" \/>\n\t<meta name=\"twitter:data1\" content=\"smeup\" \/>\n\t<meta name=\"twitter:label2\" content=\"Tempo di lettura stimato\" \/>\n\t<meta name=\"twitter:data2\" content=\"8 minuti\" \/>\n<script type=\"application\/ld+json\" class=\"yoast-schema-graph\">{\"@context\":\"https:\\\/\\\/schema.org\",\"@graph\":[{\"@type\":\"Article\",\"@id\":\"https:\\\/\\\/www.smeup.com\\\/magazine\\\/blog\\\/thread-dump-situazioni-critiche\\\/#article\",\"isPartOf\":{\"@id\":\"https:\\\/\\\/www.smeup.com\\\/magazine\\\/blog\\\/thread-dump-situazioni-critiche\\\/\"},\"author\":{\"name\":\"smeup\",\"@id\":\"https:\\\/\\\/www.smeup.com\\\/magazine\\\/#\\\/schema\\\/person\\\/194a55d96e7e52223a84ff78468bf5c7\"},\"headline\":\"Thread dump in situazioni critiche &#8211; 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