Write symbolized jemalloc profiles (eliminating the need for a binary during heap profile generation)#93099
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azat merged 3 commits intoClickHouse:masterfrom Jan 1, 2026
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yariks5s
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Dec 31, 2025
We already have "official documentation"
It was inconvenience for a long time that you need the binary for jemalloc heap profiler (different architecture, different versions and so on) This patch will write second file with a `.symbolized` prefix, for which you do not need binary anymore for `jeprof`, and you can simply run, i.e. `jeprof --text heap.0.symbolized` Internally `jeprof` supports symbolized profiles, you just need to provide a map from addresses to symbols (with some quirks) and `jeprof` will read it out of the box. Note, I've though about adding special hooks for jemalloc, but it is tricky, since you cannot everything inside generating this profile, so this implementation simply reads the file written my jemalloc, and creates a new profile with a `.symbolized` prefix.
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Changelog entry (a user-readable short description of the changes that goes into CHANGELOG.md):
Write symbolized jemalloc profiles (eliminating the need for a binary during heap profile generation)
It was inconvenience for a long time that you need the binary for jemalloc heap profiler (different architecture, different versions and so on)
This patch will write second file with a
.symbolizedprefix, for which you do not need binary anymore forjeprof, and you can simply run, i.e.jeprof --text heap.0.symbolizedInternally
jeprofsupports symbolized profiles, you just need to provide a map from addresses to symbols (with some quirks) andjeprofwill read it out of the box.Note, I've though about adding special hooks for jemalloc, but it is tricky, since you cannot everything inside generating this profile, so this implementation simply reads the file written my jemalloc, and creates a new profile with a
.symbolizedprefix.Also note that query execution time for
SYSTEM JEMALLOC FLUSH PROFILEincreased to 10 seconds (egh, handling inlines is slow, in comparison plainjeprofworks way slower, butjeprof --tools addr2line:/usr/bin/llvm-addr2line,nm:/usr/bin/llvm-nm,objdump:/usr/bin/objdump,c++filt:/usr/bin/llvm-cxxfilttakes ~90 seconds). And since it takes time, it is done only forSYSTEM JEMALLOC FLUSH PROFILE, and not forjemalloc_flush_profile_interval_bytes/jemalloc_flush_profile_on_memory_exceededP.S. I've compared the flamegraphs w/ symbolized profiles and w/o, and I did not noticed any difference except for differences in inline demangling, but this should be minor