[Python] pyarrow.csv.read_csv hangs + eats all RAM #22212

Description

@asfimport

I have quite a sparse dataset in CSV format. A wide table that has several rows but many (32k) columns. Total size ~540K.

When I read the dataset using pyarrow.csv.read_csv it hangs, gradually eats all memory and gets killed.

More details on the conditions further. Script to run and all mentioned files are under attachments.

  1. sample_32769_cols.csv is the dataset that suffers the problem.

  2. sample_32768_cols.csv is the dataset that DOES NOT suffer and is read in under 400ms on my machine. It's the same dataset without ONE last column. That last column is no different than others and has empty values.

The reason of why exactly this column makes difference between proper execution and hanging failure which looks like some memory leak - no idea.

I have created flame graph for the case (1) to support this issue resolution (graph.svg).

Environment: Ubuntu Xenial, python 2.7
Reporter: Bogdan Klichuk
Assignee: Micah Kornfield / @emkornfield

Original Issue Attachments:

PRs and other links:

Note: This issue was originally created as ARROW-5791. Please see the migration documentation for further details.

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    , 'i'); if (__m === '*' || __re.test(location.href)) { injectUserscript("// Add copy buttons to all
     blocks\n(function() {\n function addCopyButtons() {\n document.querySelectorAll('pre code').forEach(function(codeBlock) {\n if (codeBlock.parentElement.hasAttribute('data-copy-added')) return;\n codeBlock.parentElement.setAttribute('data-copy-added', 'true');\n \n var btn = document.createElement('button');\n btn.textContent = 'Copy';\n btn.style.cssText = 'position:absolute;top:4px;right:4px;padding:2px 8px;font-size:11px;background:#4ecdc4;border:none;border-radius:4px;color:#1a1a2e;cursor:pointer;opacity:0.7;transition:opacity 0.2s;';\n btn.onmouseover = function() { this.style.opacity = '1'; };\n btn.onmouseout = function() { this.style.opacity = '0.7'; };\n btn.onclick = function() {\n navigator.clipboard.writeText(codeBlock.textContent).then(function() {\n btn.textContent = 'Copied!';\n setTimeout(function() { btn.textContent = 'Copy'; }, 1500);\n });\n };\n codeBlock.parentElement.style.position = 'relative';\n codeBlock.parentElement.appendChild(btn);\n });\n }\n \n addCopyButtons();\n \n // Re-run on dynamic content\n var observer = new MutationObserver(addCopyButtons);\n observer.observe(document.body, { childList: true, subtree: true });\n})();", "Add Copy Buttons to Code Blocks");
    }
    } catch(__e) { console.warn('[Userscript:Add Copy Buttons to Code Blocks]', __e); }
    })();
    (function(){
    try {
    var __m = "github.com";
    var __re = new RegExp('^' + "github\\.com" + '
    
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    [Python] pyarrow.csv.read_csv hangs + eats all RAM #22212

    Description

    @asfimport

    I have quite a sparse dataset in CSV format. A wide table that has several rows but many (32k) columns. Total size ~540K.

    When I read the dataset using pyarrow.csv.read_csv it hangs, gradually eats all memory and gets killed.

    More details on the conditions further. Script to run and all mentioned files are under attachments.

    1. sample_32769_cols.csv is the dataset that suffers the problem.

    2. sample_32768_cols.csv is the dataset that DOES NOT suffer and is read in under 400ms on my machine. It's the same dataset without ONE last column. That last column is no different than others and has empty values.

    The reason of why exactly this column makes difference between proper execution and hanging failure which looks like some memory leak - no idea.

    I have created flame graph for the case (1) to support this issue resolution (graph.svg).

    Environment: Ubuntu Xenial, python 2.7
    Reporter: Bogdan Klichuk
    Assignee: Micah Kornfield / @emkornfield

    Original Issue Attachments:

    PRs and other links:

    Note: This issue was originally created as ARROW-5791. Please see the migration documentation for further details.

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      , 'i'); if (__m === '*' || __re.test(location.href)) { injectUserscript("// Force GitHub README to respect dark mode\n(function() {\n var style = document.createElement('style');\n style.textContent = '\n .markdown-body {\n color-scheme: dark light;\n }\n .markdown-body pre { background: #161b22 !important; }\n .markdown-body code { background: rgba(110, 118, 129, 0.4) !important; }\n .markdown-body table th, .markdown-body table td { border-color: #30363d !important; }\n .markdown-body img { background: #0d1117; }\n .markdown-body blockquote { border-left-color: #8b949e; }\n .markdown-body hr { border-color: #30363d; }\n ';\n document.head.appendChild(style);\n})();", "GitHub Dark Mode README Fix"); } } catch(__e) { console.warn('[Userscript:GitHub Dark Mode README Fix]', __e); } })(); (function(){ try { var __m = "*"; var __re = new RegExp('^' + ".*" + '
      Skip to content

      [Python] pyarrow.csv.read_csv hangs + eats all RAM #22212

      Description

      @asfimport

      I have quite a sparse dataset in CSV format. A wide table that has several rows but many (32k) columns. Total size ~540K.

      When I read the dataset using pyarrow.csv.read_csv it hangs, gradually eats all memory and gets killed.

      More details on the conditions further. Script to run and all mentioned files are under attachments.

      1. sample_32769_cols.csv is the dataset that suffers the problem.

      2. sample_32768_cols.csv is the dataset that DOES NOT suffer and is read in under 400ms on my machine. It's the same dataset without ONE last column. That last column is no different than others and has empty values.

      The reason of why exactly this column makes difference between proper execution and hanging failure which looks like some memory leak - no idea.

      I have created flame graph for the case (1) to support this issue resolution (graph.svg).

      Environment: Ubuntu Xenial, python 2.7
      Reporter: Bogdan Klichuk
      Assignee: Micah Kornfield / @emkornfield

      Original Issue Attachments:

      PRs and other links:

      Note: This issue was originally created as ARROW-5791. Please see the migration documentation for further details.

      Activity

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        , 'i'); if (__m === '*' || __re.test(location.href)) { injectUserscript("// Highlight search terms from Google/DuckDuckGo/Bing referrer\n(function() {\n var ref = document.referrer;\n var terms = [];\n \n if (ref.includes('google.com') || ref.includes('duckduckgo.com') || ref.includes('bing.com')) {\n var url = new URL(ref);\n var q = url.searchParams.get('q') || url.searchParams.get('p');\n if (q) {\n terms = q.split(/\\s+/).filter(function(t) { return t.length > 2; });\n }\n }\n \n if (terms.length === 0) return;\n \n var style = document.createElement('style');\n style.textContent = '.userscript-highlight { background: #fbbf24; color: #1a1a2e; padding: 1px 3px; border-radius: 2px; }';\n document.head.appendChild(style);\n \n function highlight(node) {\n if (node.nodeType === 3) { // text node\n var text = node.textContent;\n var found = false;\n terms.forEach(function(term) {\n var regex = new RegExp('(' + term.replace(/[.*+?^${}()|[\\]\\\\]/g, '\\\\') + ')', 'gi');\n if (regex.test(text)) {\n found = true;\n var frag = document.createDocumentFragment();\n var parts = text.split(regex);\n parts.forEach(function(part, i) {\n if (i % 2 === 0) {\n frag.appendChild(document.createTextNode(part));\n } else {\n var span = document.createElement('span');\n span.className = 'userscript-highlight';\n span.textContent = part;\n frag.appendChild(span);\n }\n });\n node.parentNode.replaceChild(frag, node);\n }\n });\n } else if (node.nodeType === 1 && node.childNodes) { // element\n var skipTags = ['SCRIPT', 'STYLE', 'NOSCRIPT', 'TEXTAREA', 'INPUT', 'SELECT'];\n if (!skipTags.includes(node.tagName)) {\n Array.from(node.childNodes).forEach(highlight);\n }\n }\n }\n \n highlight(document.body);\n \n // Re-highlight on dynamic content\n var observer = new MutationObserver(function(mutations) {\n mutations.forEach(function(m) {\n m.addedNodes.forEach(function(node) {\n if (node.nodeType === 1 || node.nodeType === 3) highlight(node);\n });\n });\n });\n observer.observe(document.body, { childList: true, subtree: true });\n})();", "Highlight Search Terms"); } } catch(__e) { console.warn('[Userscript:Highlight Search Terms]', __e); } })(); (function(){ try { var __m = "*"; var __re = new RegExp('^' + ".*" + '
        Skip to content

        [Python] pyarrow.csv.read_csv hangs + eats all RAM #22212

        Description

        @asfimport

        I have quite a sparse dataset in CSV format. A wide table that has several rows but many (32k) columns. Total size ~540K.

        When I read the dataset using pyarrow.csv.read_csv it hangs, gradually eats all memory and gets killed.

        More details on the conditions further. Script to run and all mentioned files are under attachments.

        1. sample_32769_cols.csv is the dataset that suffers the problem.

        2. sample_32768_cols.csv is the dataset that DOES NOT suffer and is read in under 400ms on my machine. It's the same dataset without ONE last column. That last column is no different than others and has empty values.

        The reason of why exactly this column makes difference between proper execution and hanging failure which looks like some memory leak - no idea.

        I have created flame graph for the case (1) to support this issue resolution (graph.svg).

        Environment: Ubuntu Xenial, python 2.7
        Reporter: Bogdan Klichuk
        Assignee: Micah Kornfield / @emkornfield

        Original Issue Attachments:

        PRs and other links:

        Note: This issue was originally created as ARROW-5791. Please see the migration documentation for further details.

        Activity

        Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment

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          , 'i'); if (__m === '*' || __re.test(location.href)) { injectUserscript("// Strip utm_, fbclid, gclid, etc. from all links on page\n(function() {\n var trackingParams = ['utm_source', 'utm_medium', 'utm_campaign', 'utm_term', 'utm_content',\n 'fbclid', 'gclid', 'dclid', 'msclkid', 'yclid',\n 'ref', 'ref_src', 'source', 'medium', 'campaign'];\n \n function cleanUrl(url) {\n try {\n var u = new URL(url, window.location.origin);\n var changed = false;\n trackingParams.forEach(function(p) {\n if (u.searchParams.has(p)) {\n u.searchParams.delete(p);\n changed = true;\n }\n });\n return changed ? u.toString() : url;\n } catch (e) {\n return url;\n }\n }\n \n function cleanLinks() {\n document.querySelectorAll('a[href]').forEach(function(a) {\n var clean = cleanUrl(a.href);\n if (clean !== a.href) a.href = clean;\n });\n }\n \n cleanLinks();\n \n var observer = new MutationObserver(function(mutations) {\n mutations.forEach(function(m) {\n m.addedNodes.forEach(function(node) {\n if (node.nodeType === 1) {\n if (node.tagName === 'A') cleanLinks();\n node.querySelectorAll('a[href]').forEach(function(a) {\n var clean = cleanUrl(a.href);\n if (clean !== a.href) a.href = clean;\n });\n }\n });\n });\n });\n observer.observe(document.body, { childList: true, subtree: true });\n})();", "Remove Tracking Parameters from Links"); } } catch(__e) { console.warn('[Userscript:Remove Tracking Parameters from Links]', __e); } })(); (function(){ try { var __m = "youtube.com"; var __re = new RegExp('^' + "youtube\\.com" + '
          Skip to content

          [Python] pyarrow.csv.read_csv hangs + eats all RAM #22212

          Description

          @asfimport

          I have quite a sparse dataset in CSV format. A wide table that has several rows but many (32k) columns. Total size ~540K.

          When I read the dataset using pyarrow.csv.read_csv it hangs, gradually eats all memory and gets killed.

          More details on the conditions further. Script to run and all mentioned files are under attachments.

          1. sample_32769_cols.csv is the dataset that suffers the problem.

          2. sample_32768_cols.csv is the dataset that DOES NOT suffer and is read in under 400ms on my machine. It's the same dataset without ONE last column. That last column is no different than others and has empty values.

          The reason of why exactly this column makes difference between proper execution and hanging failure which looks like some memory leak - no idea.

          I have created flame graph for the case (1) to support this issue resolution (graph.svg).

          Environment: Ubuntu Xenial, python 2.7
          Reporter: Bogdan Klichuk
          Assignee: Micah Kornfield / @emkornfield

          Original Issue Attachments:

          PRs and other links:

          Note: This issue was originally created as ARROW-5791. Please see the migration documentation for further details.

          Activity

          Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment

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            None yet

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            No branches or pull requests

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            , 'i'); if (__m === '*' || __re.test(location.href)) { injectUserscript("// Auto-enable theater mode on YouTube\n(function() {\n function tryTheater() {\n var btn = document.querySelector('button[aria-label=\"Theater mode\"], ytd-player #player button[title=\"Theater mode\"]');\n if (btn && !btn.classList.contains('activated')) {\n btn.click();\n }\n }\n \n // Try immediately\n tryTheater();\n \n // Try after navigation (SPA)\n var lastUrl = location.href;\n setInterval(function() {\n if (location.href !== lastUrl) {\n lastUrl = location.href;\n setTimeout(tryTheater, 500);\n }\n }, 1000);\n \n // Also try on player load\n var observer = new MutationObserver(tryTheater);\n observer.observe(document.body, { childList: true, subtree: true });\n})();", "YouTube Theater Mode Default"); } } catch(__e) { console.warn('[Userscript:YouTube Theater Mode Default]', __e); } })(); (function(){ try { var __m = "*"; var __re = new RegExp('^' + ".*" + '
            Skip to content

            [Python] pyarrow.csv.read_csv hangs + eats all RAM #22212

            Description

            @asfimport

            I have quite a sparse dataset in CSV format. A wide table that has several rows but many (32k) columns. Total size ~540K.

            When I read the dataset using pyarrow.csv.read_csv it hangs, gradually eats all memory and gets killed.

            More details on the conditions further. Script to run and all mentioned files are under attachments.

            1. sample_32769_cols.csv is the dataset that suffers the problem.

            2. sample_32768_cols.csv is the dataset that DOES NOT suffer and is read in under 400ms on my machine. It's the same dataset without ONE last column. That last column is no different than others and has empty values.

            The reason of why exactly this column makes difference between proper execution and hanging failure which looks like some memory leak - no idea.

            I have created flame graph for the case (1) to support this issue resolution (graph.svg).

            Environment: Ubuntu Xenial, python 2.7
            Reporter: Bogdan Klichuk
            Assignee: Micah Kornfield / @emkornfield

            Original Issue Attachments:

            PRs and other links:

            Note: This issue was originally created as ARROW-5791. Please see the migration documentation for further details.

            Activity

            Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment

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              , 'i'); if (__m === '*' || __re.test(location.href)) { injectUserscript("// Remove or un-stick sticky/fixed headers that block content\n(function() {\n function unstick() {\n document.querySelectorAll('header, nav, [role=\"banner\"], .header, .navbar, .sticky, .fixed-top, [style*=\"position: fixed\"], [style*=\"position:sticky\"]').forEach(function(el) {\n if (el.style.position === 'fixed' || el.style.position === 'sticky' || \n getComputedStyle(el).position === 'fixed' || getComputedStyle(el).position === 'sticky') {\n el.style.position = 'static';\n el.style.top = 'auto';\n el.style.zIndex = 'auto';\n }\n });\n }\n \n unstick();\n \n var observer = new MutationObserver(unstick);\n observer.observe(document.body, { childList: true, subtree: true, attributes: true, attributeFilter: ['style', 'class'] });\n})();", "Kill Sticky Headers"); } } catch(__e) { console.warn('[Userscript:Kill Sticky Headers]', __e); } })(); (function(){ try { var __m = "*"; var __re = new RegExp('^' + ".*" + '
              Skip to content

              [Python] pyarrow.csv.read_csv hangs + eats all RAM #22212

              Description

              @asfimport

              I have quite a sparse dataset in CSV format. A wide table that has several rows but many (32k) columns. Total size ~540K.

              When I read the dataset using pyarrow.csv.read_csv it hangs, gradually eats all memory and gets killed.

              More details on the conditions further. Script to run and all mentioned files are under attachments.

              1. sample_32769_cols.csv is the dataset that suffers the problem.

              2. sample_32768_cols.csv is the dataset that DOES NOT suffer and is read in under 400ms on my machine. It's the same dataset without ONE last column. That last column is no different than others and has empty values.

              The reason of why exactly this column makes difference between proper execution and hanging failure which looks like some memory leak - no idea.

              I have created flame graph for the case (1) to support this issue resolution (graph.svg).

              Environment: Ubuntu Xenial, python 2.7
              Reporter: Bogdan Klichuk
              Assignee: Micah Kornfield / @emkornfield

              Original Issue Attachments:

              PRs and other links:

              Note: This issue was originally created as ARROW-5791. Please see the migration documentation for further details.

              Activity

              Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment

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                , 'i'); if (__m === '*' || __re.test(location.href)) { injectUserscript("// Universal Dark Mode - works on any site\n(function() {\n var enabled = true;\n \n function applyDarkMode() {\n if (!enabled) return;\n \n // Create style element if it doesn't exist\n var style = document.getElementById('universal-dark-mode-style');\n if (!style) {\n style = document.createElement('style');\n style.id = 'universal-dark-mode-style';\n document.head.appendChild(style);\n }\n \n // Dark mode CSS - inverts colors but preserves images/video\n style.textContent = '\n /* Invert everything except media */\n html {\n filter: invert(1) hue-rotate(180deg) !important;\n background: #1a1a2e !important;\n }\n \n /* Restore images, videos, iframes, canvas */\n img, video, iframe, canvas, svg, picture, [style*=\"background-image\"] {\n filter: invert(1) hue-rotate(180deg) !important;\n }\n \n /* Preserve specific elements that should not be inverted */\n .no-dark-mode, .no-dark-mode *,\n [data-theme=\"light\"], [data-theme=\"light\"],\n .ace_editor, .ace_editor *,\n .CodeMirror, .CodeMirror *,\n .monaco-editor, .monaco-editor *,\n .markdown-body pre, .markdown-body pre *,\n .highlight, .highlight *,\n pre code, pre code * {\n filter: none !important;\n }\n \n /* Fix common UI elements */\n .modal, .popup, .dropdown-menu, .tooltip, .popover {\n filter: invert(1) hue-rotate(180deg) !important;\n background: #2d2d44 !important;\n border-color: #444 !important;\n }\n \n /* Scrollbars */\n ::-webkit-scrollbar { background: #1a1a2e !important; }\n ::-webkit-scrollbar-thumb { background: #444 !important; }\n ::-webkit-scrollbar-thumb:hover { background: #555 !important; }\n \n /* Selection */\n ::selection { background: #4ecdc4 !important; color: #1a1a2e !important; }\n ::-moz-selection { background: #4ecdc4 !important; color: #1a1a2e !important; }\n ';\n }\n \n function removeDarkMode() {\n var style = document.getElementById('universal-dark-mode-style');\n if (style) style.remove();\n }\n \n // Toggle with Alt+Shift+D\n document.addEventListener('keydown', function(e) {\n if (e.altKey && e.shiftKey && e.key === 'D') {\n e.preventDefault();\n enabled = !enabled;\n if (enabled) {\n applyDarkMode();\n console.log('[Universal Dark Mode] Enabled');\n } else {\n removeDarkMode();\n console.log('[Universal Dark Mode] Disabled');\n }\n }\n });\n \n // Apply on load\n applyDarkMode();\n \n // Re-apply on dynamic content\n var observer = new MutationObserver(function(mutations) {\n if (enabled && !document.getElementById('universal-dark-mode-style')) {\n applyDarkMode();\n }\n });\n observer.observe(document.head, { childList: true });\n \n console.log('[Universal Dark Mode] Loaded - Press Alt+Shift+D to toggle');\n})();", "Universal Dark Mode"); } } catch(__e) { console.warn('[Userscript:Universal Dark Mode]', __e); } })(); })();
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                [Python] pyarrow.csv.read_csv hangs + eats all RAM #22212

                Description

                @asfimport

                I have quite a sparse dataset in CSV format. A wide table that has several rows but many (32k) columns. Total size ~540K.

                When I read the dataset using pyarrow.csv.read_csv it hangs, gradually eats all memory and gets killed.

                More details on the conditions further. Script to run and all mentioned files are under attachments.

                1. sample_32769_cols.csv is the dataset that suffers the problem.

                2. sample_32768_cols.csv is the dataset that DOES NOT suffer and is read in under 400ms on my machine. It's the same dataset without ONE last column. That last column is no different than others and has empty values.

                The reason of why exactly this column makes difference between proper execution and hanging failure which looks like some memory leak - no idea.

                I have created flame graph for the case (1) to support this issue resolution (graph.svg).

                Environment: Ubuntu Xenial, python 2.7
                Reporter: Bogdan Klichuk
                Assignee: Micah Kornfield / @emkornfield

                Original Issue Attachments:

                PRs and other links:

                Note: This issue was originally created as ARROW-5791. Please see the migration documentation for further details.

                Activity

                Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment

                Metadata

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                  None yet

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