@@ -12,8 +12,8 @@ For information on catalog configuration properties, see :doc:`Connectors </conn
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For information on Presto C++ session properties, see :doc: `properties-session `.
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- NOTE: While some of the configuration properties below with "-gb" in their names
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- show gigabytes (gB; 1 gB equals 1000000000 B), it is actually
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+ NOTE: While some of the configuration properties below with "-gb" in their names
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+ show gigabytes (gB; 1 gB equals 1000000000 B), it is actually
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gibibytes (GiB; 1 GiB equals 1073741824 B).
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.. contents ::
@@ -137,8 +137,8 @@ The configuration properties of Presto C++ workers are described here, in alphab
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1) Memory used by the queries as specified in ``query-memory-gb ``; 2) Memory used by the
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system, such as disk spilling and cache prefetch.
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- Set ``system-memory-gb `` to about 90% of available machine memory of the deployment.
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- This allows some buffer room to handle unaccounted memory in order to prevent out-of-memory conditions.
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+ Set ``system-memory-gb `` to about 90% of available machine memory of the deployment.
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+ This allows some buffer room to handle unaccounted memory in order to prevent out-of-memory conditions.
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The default value of 57 gb is calculated based on available machine memory of 64 gb.
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@@ -162,6 +162,51 @@ The configuration properties of Presto C++ workers are described here, in alphab
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storage used for spilling. If it is zero, then there is no limit and spilling
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might exhaust the storage or takes too long to run.
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+
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+ ``spill-enabled ``
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+ ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
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+
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+ * **Type: ** ``boolean ``
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+ * **Default value: ** ``false ``
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+
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+ Try spilling memory to disk to avoid exceeding memory limits for the query.
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+
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+ Spilling works by offloading memory to disk. This process can allow a query with a large memory
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+ footprint to pass at the cost of slower execution times. Currently, spilling is supported only for
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+ aggregations and joins (inner and outer), so this property will not reduce memory usage required for
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+ window functions, sorting and other join types.
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+
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+
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+ ``join-spill-enabled ``
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+ ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
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+
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+ * **Type: ** ``boolean ``
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+ * **Default value: ** ``true ``
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+
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+ When ``spill_enabled `` is ``true ``, this determines whether Presto will try spilling memory to disk for joins to
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+ avoid exceeding memory limits for the query.
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+
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+
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+ ``aggregation-spill-enabled ``
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+ ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
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+
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+ * **Type: ** ``boolean ``
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+ * **Default value: ** ``true ``
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+
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+ When ``spill_enabled `` is ``true ``, this determines whether Presto will try spilling memory to disk for aggregations to
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+ avoid exceeding memory limits for the query.
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+
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+
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+ ``order-by-spill-enabled ``
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+ ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
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+
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+ * **Type: ** ``boolean ``
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+ * **Default value: ** ``true ``
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+
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+ When ``spill_enabled `` is ``true ``, this determines whether Presto will try spilling memory to disk for order by to
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+ avoid exceeding memory limits for the query.
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+
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+
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``shared-arbitrator.reserved-capacity ``
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^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
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@@ -321,32 +366,32 @@ The configuration properties of AsyncDataCache and SSD cache are described here.
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^^^^^^^^^^^^^^^^^^^^^^^^
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* **Type: ** ``string ``
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* **Default value: ** ``/mnt/flash/async_cache. ``
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-
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+
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The path of the directory that is mounted onto the SSD.
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``async-cache-max-ssd-write-ratio ``
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^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
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* **Type: ** ``double ``
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* **Default value: ** ``0.7 ``
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- The maximum ratio of the number of in-memory cache entries written to the SSD cache
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- over the total number of cache entries. Use this to control SSD cache write rate,
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+
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+ The maximum ratio of the number of in-memory cache entries written to the SSD cache
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+ over the total number of cache entries. Use this to control SSD cache write rate,
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once the ratio exceeds this threshold then we stop writing to the SSD cache.
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``async-cache-ssd-savable-ratio ``
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^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
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* **Type: ** ``double ``
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* **Default value: ** ``0.125 ``
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-
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+
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The min ratio of SSD savable (in-memory) cache space over the total cache space.
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- Once the ratio exceeds this limit, we start writing SSD savable cache entries
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+ Once the ratio exceeds this limit, we start writing SSD savable cache entries
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into SSD cache.
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``async-cache-min-ssd-savable-bytes ``
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^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
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* **Type: ** ``integer ``
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* **Default value: ** ``16777216 ``
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-
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+
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Min SSD savable (in-memory) cache space to start writing SSD savable cache entries into SSD cache.
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The default value ``16777216 `` is 16 MB.
@@ -358,61 +403,61 @@ The configuration properties of AsyncDataCache and SSD cache are described here.
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^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
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* **Type: ** ``string ``
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* **Default value: ** ``0s ``
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+
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The interval for persisting in-memory cache to SSD. Set this configuration to a non-zero value to
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activate periodic cache persistence.
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- The following time units are supported:
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-
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+
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+ The following time units are supported:
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+
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ns, us, ms, s, m, h, d
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``async-cache-ssd-disable-file-cow ``
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^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
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* **Type: ** ``bool ``
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* **Default value: ** ``false ``
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+
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In file systems such as btrfs that support cow (copy on write), the SSD cache can use all of the SSD
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space and stop working. To prevent that, use this option to disable cow for cache files.
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``ssd-cache-checksum-enabled ``
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^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
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* **Type: ** ``bool ``
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* **Default value: ** ``false ``
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- When enabled, a CRC-based checksum is calculated for each cache entry written to SSD.
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+
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+ When enabled, a CRC-based checksum is calculated for each cache entry written to SSD.
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The checksum is stored in the next checkpoint file.
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``ssd-cache-read-verification-enabled ``
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^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
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* **Type: ** ``bool ``
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* **Default value: ** ``false ``
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- When enabled, the checksum is recalculated and verified against the stored value when
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+ When enabled, the checksum is recalculated and verified against the stored value when
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cache data is loaded from the SSD.
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``cache.velox.ttl-enabled ``
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^^^^^^^^^^^^^^^^^^^^^^^^^^^
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* **Type: ** ``bool ``
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* **Default value: ** ``false ``
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+
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Enable TTL for AsyncDataCache and SSD cache.
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``cache.velox.ttl-threshold ``
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^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
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* **Type: ** ``string ``
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* **Default value: ** ``2d ``
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+
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TTL duration for AsyncDataCache and SSD cache entries.
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The following time units are supported:
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ns, us, ms, s, m, h, d
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``cache.velox.ttl-check-interval ``
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^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
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* **Type: ** ``string ``
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* **Default value: ** ``1h ``
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The periodic duration to apply cache TTL and evict AsyncDataCache and SSD cache entries.
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Memory Checker Properties
@@ -439,9 +484,9 @@ server is under low memory pressure.
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Specifies the system memory limit that triggers the memory pushback or heap dump if
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the server memory usage is beyond this limit. A value of zero means no limit is set.
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- This only applies if ``system-mem-pushback-enabled `` is ``true ``.
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- Set ``system-mem-limit-gb `` to be greater than or equal to system-memory-gb but not
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- higher than the available machine memory of the deployment.
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+ This only applies if ``system-mem-pushback-enabled `` is ``true ``.
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+ Set ``system-mem-limit-gb `` to be greater than or equal to system-memory-gb but not
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+ higher than the available machine memory of the deployment.
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The default value of 60 gb is calculated based on available machine memory of 64 gb.
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``system-mem-shrink-gb ``
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