feat(config): add jemalloc_background_thread option#1260
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Adds a `[general]` option (also PGDOG_JEMALLOC_BACKGROUND_THREAD env), default off, that enables jemalloc's background purge threads at startup via tikv-jemalloc-ctl — equivalent to _RJEM_MALLOC_CONF=background_thread:true, so freed memory is returned to the OS after allocation bursts without requiring the env var. No-op on non-jemalloc builds (test/msvc). Refs pgdogdev#1230.
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Assert the default (false) and env-var (PGDOG_JEMALLOC_BACKGROUND_THREAD) handling of the new option.
sgrif
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sgrif
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This doesn't need to be a config, we should be enabling this by default on all supported platforms. We don't need to be logging errors, this will only return an error on unsupported platforms
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/cc @levkk Since you asked for this to be a config option. I've never seen a scenario where jemalloc bg threads could be enabled and it wasn't desirable |
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It was probably pre-second coffee and I wasn't thinking straight. I don't know why bg threads are disabled by default, so I was just thinking maybe we need to find out before unleashing this on everyone, so maybe an env var or something? Not sure. |
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Yeah, I don't think we need to worry about anything like that. This is pretty universally recommended to be enabled |
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Implements the config-based option suggested in #1230.
Adds a
[general]optionjemalloc_background_thread(defaultfalse, also settable viaPGDOG_JEMALLOC_BACKGROUND_THREAD). When enabled, PgDog turns on jemalloc's background purge threads at startup viatikv-jemalloc-ctl— the programmatic equivalent of_RJEM_MALLOC_CONF=background_thread:true— so freed memory is returned to the OS after bursts of large allocations instead of accumulating as retained dirty pages, without operators having to set the env var.test,msvc)..schema/).Docs: pgdogdev/docs#100.
Refs #1230.