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5253a7f650
Cgroups allows to change the amount of memory available to a process
while it runs. The previous logic calculated the amount of available
memory only once at server startup. As a result, memory thresholds set
via cgroups were not picked up when the settings changed. We now always
incorporate the current limits during re-configuraton.
Note 1: getMemoryAmount() opens/reads a file which is potentially
expensive. Should be fine though since that happens only when
the server configuration changes.
Note 2: An better approach would be to treat cgroup limit changes as
another trigger for ClickHouse server re-configuration (which
currently only happens when the config files change). Shied away
from that for now because of the case that when the cgroup limit
is lowered, there is no guarantee that ClickHouse can shrink the
memory amount accordingly in time (afaik, it does so only lazily
by denying new allocations). As a result, the OOM killer would
kill the server. The same will happen with this PR but at a
lower implementation complexity.
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| .. | ||
| config.d | ||
| js | ||
| users.d | ||
| .gitignore | ||
| clickhouse-server.cpp | ||
| CMakeLists.txt | ||
| config.xml | ||
| config.yaml.example | ||
| dashboard.html | ||
| embedded.xml | ||
| MetricsTransmitter.cpp | ||
| MetricsTransmitter.h | ||
| play.html | ||
| resources.cpp | ||
| Server.cpp | ||
| Server.h | ||
| users.xml | ||
| users.yaml.example | ||