- Properties Reference
- General Properties
- Memory Management Properties
- Spilling Properties
experimental.spill-enabled
experimental.join-spill-enabled
experimental.aggregation-spill-enabled
experimental.distinct-aggregation-spill-enabled
experimental.order-by-aggregation-spill-enabled
experimental.window-spill-enabled
experimental.order-by-spill-enabled
experimental.spiller.task-spilling-strategy
experimental.memory-revoking-threshold
experimental.memory-revoking-target
experimental.query-limit-spill-enabled
experimental.spiller.max-revocable-task-memory
experimental.max-revocable-memory-per-node
experimental.spiller-spill-path
experimental.spiller-max-used-space-threshold
experimental.spiller-threads
experimental.max-spill-per-node
experimental.query-max-spill-per-node
experimental.aggregation-operator-unspill-memory-limit
experimental.spill-compression-enabled
experimental.spill-encryption-enabled
experimental.spiller.single-stream-spiller-choice
experimental.spiller.spiller-temp-storage
experimental.temp-storage-buffer-size
- Exchange Properties
- Task Properties
- Node Scheduler Properties
- Optimizer Properties
optimizer.dictionary-aggregation
optimizer.optimize-hash-generation
optimizer.optimize-metadata-queries
optimizer.optimize-single-distinct
optimizer.push-aggregation-through-join
optimizer.push-table-write-through-union
optimizer.join-reordering-strategy
optimizer.max-reordered-joins
optimizer.use-defaults-for-correlated-aggregation-pushdown-through-outer-joins
optimizer.rewrite-expression-with-constant-variable
optimizer.history-based-optimizer-plan-canonicalization-strategies
optimizer.track-history-stats-from-failed-queries
optimizer.log-plans-used-in-history-based-optimizer
optimizer.exploit-constraints
optimizer.confidence-based-broadcast
optimizer.treat-low-confidence-zero-estimation-as-unknown
optimizer.retry-query-with-history-based-optimization
- Planner Properties
- Regular Expression Function Properties
- Logging Properties
- Legacy Compatible Properties
Properties Reference
This section describes the most important config properties that may be used to tune Presto or alter its behavior when required.
The following pages are not a complete list of all configuration and session properties available in Presto, and do not include any connector-specific catalog configuration properties. For more information on catalog configuration properties, refer to the connector documentation.
General Properties
join-distribution-type
Type:
string
Allowed values:
AUTOMATIC
,PARTITIONED
,BROADCAST
Default value:
AUTOMATIC
The type of distributed join to use. When set to PARTITIONED
, presto will use hash distributed joins. When set to BROADCAST
, it will broadcast the right table to all nodes in the cluster that have data from the left table. Partitioned joins require redistributing both tables using a hash of the join key. This can be slower (sometimes substantially) than broadcast joins, but allows much larger joins. In particular broadcast joins will be faster if the right table is much smaller than the left. However, broadcast joins require that the tables on the right side of the join after filtering fit in memory on each node, whereas distributed joins only need to fit in distributed memory across all nodes. When set to AUTOMATIC
, Presto will make a cost based decision as to which distribution type is optimal. It will also consider switching the left and right inputs to the join. In AUTOMATIC
mode, Presto will default to hash distributed joins if no cost could be computed, such as if the tables do not have statistics. This can also be specified on a per-query basis using the join_distribution_type
session property.
redistribute-writes
Type:
boolean
Default value:
true
This property enables redistribution of data before writing. This can eliminate the performance impact of data skew when writing by hashing it across nodes in the cluster. It can be disabled when it is known that the output data set is not skewed in order to avoid the overhead of hashing and redistributing all the data across the network. This can also be specified on a per-query basis using the redistribute_writes
session property.
Memory Management Properties
query.max-memory-per-node
Type:
data size
Default value:
JVM max memory * 0.1
This is the max amount of user memory a query can use on a worker. User memory is allocated during execution for things that are directly attributable to or controllable by a user query. For example, memory used by the hash tables built during execution, memory used during sorting, etc. When the user memory allocation of a query on any worker hits this limit it will be killed.
query.max-total-memory-per-node
Type:
data size
Default value:
query.max-memory-per-node * 2
This is the max amount of user and system memory a query can use on a worker. System memory is allocated during execution for things that are not directly attributable to or controllable by a user query. For example, memory allocated by the readers, writers, network buffers, etc. When the sum of the user and system memory allocated by a query on any worker hits this limit it will be killed. The value of query.max-total-memory-per-node
must be greater than query.max-memory-per-node
.
query.max-memory
Type:
data size
Default value:
20GB
This is the max amount of user memory a query can use across the entire cluster. User memory is allocated during execution for things that are directly attributable to or controllable by a user query. For example, memory used by the hash tables built during execution, memory used during sorting, etc. When the user memory allocation of a query across all workers hits this limit it will be killed.
query.max-total-memory
Type:
data size
Default value:
query.max-memory * 2
This is the max amount of user and system memory a query can use across the entire cluster. System memory is allocated during execution for things that are not directly attributable to or controllable by a user query. For example, memory allocated by the readers, writers, network buffers, etc. When the sum of the user and system memory allocated by a query across all workers hits this limit it will be killed. The value of query.max-total-memory
must be greater than query.max-memory
.
memory.heap-headroom-per-node
Type:
data size
Default value:
JVM max memory * 0.3
This is the amount of memory set aside as headroom/buffer in the JVM heap for allocations that are not tracked by Presto.
query.low-memory-killer.policy
Type:
string
Default value:
none
The policy used for selecting the query to kill when the cluster is out of memory (OOM). This property can have one of the following values: none
, total-reservation
, or total-reservation-on-blocked-nodes
. none
disables the cluster OOM killer. The value of total-reservation
configures a policy that kills the query with the largest memory reservation across the cluster. The value of total-reservation-on-blocked-nodes
configures a policy that kills the query using the most memory on the workers that are out of memory (blocked).
Spilling Properties
experimental.spill-enabled
Type:
boolean
Default value:
false
Try spilling memory to disk to avoid exceeding memory limits for the query.
Spilling works by offloading memory to disk. This process can allow a query with a large memory footprint to pass at the cost of slower execution times. Currently, spilling is supported only for aggregations and joins (inner and outer), so this property will not reduce memory usage required for window functions, sorting and other join types.
Be aware that this is an experimental feature and should be used with care.
This config property can be overridden by the spill_enabled
session property.
experimental.join-spill-enabled
Type:
boolean
Default value:
true
When spill_enabled
is true
, this determines whether Presto will try spilling memory to disk for joins to avoid exceeding memory limits for the query.
This config property can be overridden by the join_spill_enabled
session property.
experimental.aggregation-spill-enabled
Type:
boolean
Default value:
true
When spill_enabled
is true
, this determines whether Presto will try spilling memory to disk for aggregations to avoid exceeding memory limits for the query.
This config property can be overridden by the aggregation_spill_enabled
session property.
experimental.distinct-aggregation-spill-enabled
Type:
boolean
Default value:
true
When aggregation_spill_enabled
is true
, this determines whether Presto will try spilling memory to disk for distinct aggregations to avoid exceeding memory limits for the query.
This config property can be overridden by the distinct_aggregation_spill_enabled
session property.
experimental.order-by-aggregation-spill-enabled
Type:
boolean
Default value:
true
When aggregation_spill_enabled
is true
, this determines whether Presto will try spilling memory to disk for order by aggregations to avoid exceeding memory limits for the query.
This config property can be overridden by the order_by_aggregation_spill_enabled
session property.
experimental.window-spill-enabled
Type:
boolean
Default value:
true
When spill_enabled
is true
, this determines whether Presto will try spilling memory to disk for window functions to avoid exceeding memory limits for the query.
This config property can be overridden by the window_spill_enabled
session property.
experimental.order-by-spill-enabled
Type:
boolean
Default value:
true
When spill_enabled
is true
, this determines whether Presto will try spilling memory to disk for order by to avoid exceeding memory limits for the query.
This config property can be overridden by the order_by_spill_enabled
session property.
experimental.spiller.task-spilling-strategy
Type:
string
Allowed values:
ORDER_BY_CREATE_TIME
,ORDER_BY_REVOCABLE_BYTES
,PER_TASK_MEMORY_THRESHOLD
Default value:
ORDER_BY_CREATE_TIME
Determines the strategy to use to choose when to revoke memory and from which tasks.
ORDER_BY_CREATE_TIME
and ORDER_BY_REVOCABLE_BYTES
will trigger spilling when the memory pool is filled beyond the experimental.memory-revoking-threshold
until the memory pool usage is below experimental.memory-revoking-target
. ORDER_BY_CREATE_TIME
will trigger revocation from older tasks first, while ORDER_BY_REVOCABLE_BYTES
will trigger revocation from tasks that are using more revocable memory first.
PER_TASK_MEMORY_THRESHOLD
will trigger spilling whenever the revocable memory used by a task exceeds experimental.spiller.max-revocable-task-memory
.
Warning
The PER_TASK_MEMORY_THRESHOLD
strategy does not trigger spilling when the memory pool is full, which can prevent the out of memory query killer from kicking in. This is particularly risky if Presto is running without a reserved memory pool.
experimental.memory-revoking-threshold
Type:
double
Minimum value:
0
Maximum value:
1
Default value:
0.9
Trigger memory revocation when the memory pool is filled above this percentage.
experimental.memory-revoking-target
Type:
double
Minimum value:
0
Maximum value:
1
Default value:
0.5
When revoking memory, try to revoke enough that the memory pool is filled below the target percentage at the end.
experimental.query-limit-spill-enabled
Type:
boolean
Default value:
false
When spill is enabled and experimental.spiller.task-spilling-strategy
is ORDER_BY_CREATE_TIME
or ORDER_BY_REVOCABLE_BYTES
, then also spill revocable memory from a query whenever its combined revocable, user, and system memory exceeds query_max_total_memory_per_node
. This allows queries to have more consistent performance regardless of the load on the cluster at the cost of less efficient use of available memory.
experimental.spiller.max-revocable-task-memory
Type:
data size
Default value:
500MB
If experimental.spiller.task-spilling-strategy
is set to PER_TASK_MEMORY_THRESHOLD
, this property defines the threshold at which to trigger spilling for a task. This property is ignored for any other spilling strategy.
experimental.max-revocable-memory-per-node
Type:
data size
Default value:
16GB
This property defines the amount of revocable memory a query can use on each node
experimental.spiller-spill-path
Type:
string
No default value. Must be set when spilling is enabled
Directory where spilled content will be written. It can be a comma separated list to spill simultaneously to multiple directories, which helps to utilize multiple drives installed in the system.
It is not recommended to spill to system drives. Most importantly, do not spill to the drive on which the JVM logs are written, as disk overutilization might cause JVM to pause for lengthy periods, causing queries to fail.
experimental.spiller-max-used-space-threshold
Type:
double
Default value:
0.9
If disk space usage ratio of a given spill path is above this threshold, this spill path will not be eligible for spilling.
experimental.spiller-threads
Type:
integer
Default value:
4
Number of spiller threads. Increase this value if the default is not able to saturate the underlying spilling device (for example, when using RAID).
experimental.max-spill-per-node
Type:
data size
Default value:
100 GB
Max spill space to be used by all queries on a single node.
experimental.query-max-spill-per-node
Type:
data size
Default value:
100 GB
Max spill space to be used by a single query on a single node.
experimental.aggregation-operator-unspill-memory-limit
Type:
data size
Default value:
4 MB
Limit for memory used for unspilling a single aggregation operator instance. This config property can be overridden by the aggregation_operator_unspill_memory_limit
session property
experimental.spill-compression-enabled
Type:
boolean
Default value:
false
Enables data compression for pages spilled to disk
experimental.spill-encryption-enabled
Type:
boolean
Default value:
false
Enables using a randomly generated secret key (per spill file) to encrypt and decrypt data spilled to disk
experimental.spiller.single-stream-spiller-choice
Type:
String
Default value:
LOCAL_FILE
The Single Stream Spiller to be used when spilling is enabled. There are two options LOCAL_FILE (default) and TEMP_STORAGE.
experimental.spiller.spiller-temp-storage
Type:
String
Default value:
local
Temp storage used by spiller when experimental.spiller.single-stream-spiller-choice
is set to TEMP_STORAGE
experimental.temp-storage-buffer-size
Type:
Data Size
Default value:
4KB
Size of buffer when experimental.spiller.single-stream-spiller-choice
is set to TEMP_STORAGE
Exchange Properties
Exchanges transfer data between Presto nodes for different stages of a query. Adjusting these properties may help to resolve inter-node communication issues or improve network utilization.
exchange.client-threads
Type:
integer
Minimum value:
1
Default value:
25
Number of threads used by exchange clients to fetch data from other Presto nodes. A higher value can improve performance for large clusters or clusters with very high concurrency, but excessively high values may cause a drop in performance due to context switches and additional memory usage.
exchange.concurrent-request-multiplier
Type:
integer
Minimum value:
1
Default value:
3
Multiplier determining the number of concurrent requests relative to available buffer memory. The maximum number of requests is determined using a heuristic of the number of clients that can fit into available buffer space based on average buffer usage per request times this multiplier. For example, with an exchange.max-buffer-size
of 32 MB
and 20 MB
already used and average size per request being 2MB
, the maximum number of clients is multiplier * ((32MB - 20MB) / 2MB) = multiplier * 6
. Tuning this value adjusts the heuristic, which may increase concurrency and improve network utilization.
exchange.max-buffer-size
Type:
data size
Default value:
32MB
Size of buffer in the exchange client that holds data fetched from other nodes before it is processed. A larger buffer can increase network throughput for larger clusters and thus decrease query processing time, but will reduce the amount of memory available for other usages.
exchange.max-response-size
Type:
data size
Minimum value:
1MB
Default value:
16MB
Maximum size of a response returned from an exchange request. The response will be placed in the exchange client buffer which is shared across all concurrent requests for the exchange.
Increasing the value may improve network throughput if there is high latency. Decreasing the value may improve query performance for large clusters as it reduces skew due to the exchange client buffer holding responses for more tasks (rather than hold more data from fewer tasks).
sink.max-buffer-size
Type:
data size
Default value:
32MB
Output buffer size for task data that is waiting to be pulled by upstream tasks. If the task output is hash partitioned, then the buffer will be shared across all of the partitioned consumers. Increasing this value may improve network throughput for data transferred between stages if the network has high latency or if there are many nodes in the cluster.
Task Properties
task.concurrency
Type:
integer
Restrictions: must be a power of two
Default value:
16
Default local concurrency for parallel operators such as joins and aggregations. This value should be adjusted up or down based on the query concurrency and worker resource utilization. Lower values are better for clusters that run many queries concurrently because the cluster will already be utilized by all the running queries, so adding more concurrency will result in slow downs due to context switching and other overhead. Higher values are better for clusters that only run one or a few queries at a time. This can also be specified on a per-query basis using the task_concurrency
session property.
task.http-response-threads
Type:
integer
Minimum value:
1
Default value:
100
Maximum number of threads that may be created to handle HTTP responses. Threads are created on demand and are cleaned up when idle, thus there is no overhead to a large value if the number of requests to be handled is small. More threads may be helpful on clusters with a high number of concurrent queries, or on clusters with hundreds or thousands of workers.
task.http-timeout-threads
Type:
integer
Minimum value:
1
Default value:
3
Number of threads used to handle timeouts when generating HTTP responses. This value should be increased if all the threads are frequently in use. This can be monitored via the com.facebook.presto.server:name=AsyncHttpExecutionMBean:TimeoutExecutor
JMX object. If ActiveCount
is always the same as PoolSize
, increase the number of threads.
task.info-update-interval
Type:
duration
Minimum value:
1ms
Maximum value:
10s
Default value:
3s
Controls staleness of task information, which is used in scheduling. Larger values can reduce coordinator CPU load, but may result in suboptimal split scheduling.
task.max-partial-aggregation-memory
Type:
data size
Default value:
16MB
Maximum size of partial aggregation results for distributed aggregations. Increasing this value can result in less network transfer and lower CPU utilization by allowing more groups to be kept locally before being flushed, at the cost of additional memory usage.
task.max-worker-threads
Type:
integer
Default value:
Node CPUs * 2
Sets the number of threads used by workers to process splits. Increasing this number can improve throughput if worker CPU utilization is low and all the threads are in use, but will cause increased heap space usage. Setting the value too high may cause a drop in performance due to a context switching. The number of active threads is available via the RunningSplits
property of the com.facebook.presto.execution.executor:name=TaskExecutor.RunningSplits
JXM object.
The number of threads can be configured using either an absolute value (for example, 10
) or a value relative to the number of available CPU cores (for example, 1.5C
). When using a relative value, the number of threads is calculated based on the available CPU cores multiplied by the specified factor (for example, 1.5
) and rounded to the nearest integer.
task.min-drivers
Type:
integer
Default value:
task.max-worker-threads * 2
The target number of running leaf splits on a worker. This is a minimum value because each leaf task is guaranteed at least 3
running splits. Non-leaf tasks are also guaranteed to run in order to prevent deadlocks. A lower value may improve responsiveness for new tasks, but can result in underutilized resources. A higher value can increase resource utilization, but uses additional memory.
task.writer-count
Type:
integer
Restrictions: must be a power of two
Default value:
1
The number of concurrent writer threads per worker per query. Increasing this value may increase write speed, especially when a query is not I/O bound and can take advantage of additional CPU for parallel writes (some connectors can be bottlenecked on CPU when writing due to compression or other factors). Setting this too high may cause the cluster to become overloaded due to excessive resource utilization. This can also be specified on a per-query basis using the task_writer_count
session property.
task.interrupt-runaway-splits-timeout
Type:
duration
Default value:
10m
Timeout for interrupting split threads blocked without yielding control. Only threads blocked in specific locations are interrupted. Currently this is just threads blocked in the Joni regular expression library.
Node Scheduler Properties
node-scheduler.max-splits-per-node
Type:
integer
Default value:
100
The target value for the number of splits that can be running for each worker node, assuming all splits have the standard split weight.
Using a higher value is recommended if queries are submitted in large batches (e.g., running a large group of reports periodically) or for connectors that produce many splits that complete quickly but do not support assigning split weight values to express that to the split scheduler. Increasing this value may improve query latency by ensuring that the workers have enough splits to keep them fully utilized.
When connectors do support weight based split scheduling, the number of splits assigned will depend on the weight of the individual splits. If splits are small, more of them are allowed to be assigned to each worker to compensate.
Setting this too high will waste memory and may result in lower performance due to splits not being balanced across workers. Ideally, it should be set such that there is always at least one split waiting to be processed, but not higher.
node-scheduler.max-pending-splits-per-task
Type:
integer
Default value:
10
The number of outstanding splits with the standard split weight that can be queued for each worker node for a single stage of a query, even when the node is already at the limit for total number of splits. Allowing a minimum number of splits per stage is required to prevent starvation and deadlocks.
This value must be smaller than node-scheduler.max-splits-per-node
, will usually be increased for the same reasons, and has similar drawbacks if set too high.
node-scheduler.min-candidates
Type:
integer
Minimum value:
1
Default value:
10
The minimum number of candidate nodes that will be evaluated by the node scheduler when choosing the target node for a split. Setting this value too low may prevent splits from being properly balanced across all worker nodes. Setting it too high may increase query latency and increase CPU usage on the coordinator.
node-scheduler.network-topology
Type:
string
Allowed values:
legacy
,flat
Default value:
legacy
Sets the network topology to use when scheduling splits. legacy
will ignore the topology when scheduling splits. flat
will try to schedule splits on the host where the data is located by reserving 50% of the work queue for local splits. It is recommended to use flat
for clusters where distributed storage runs on the same nodes as Presto workers.
Optimizer Properties
optimizer.dictionary-aggregation
Type:
boolean
Default value:
false
Enables optimization for aggregations on dictionaries. This can also be specified on a per-query basis using the dictionary_aggregation
session property.
optimizer.optimize-hash-generation
Type:
boolean
Default value:
true
Compute hash codes for distribution, joins, and aggregations early during execution, allowing result to be shared between operations later in the query. This can reduce CPU usage by avoiding computing the same hash multiple times, but at the cost of additional network transfer for the hashes. In most cases it will decrease overall query processing time. This can also be specified on a per-query basis using the optimize_hash_generation
session property.
It is often helpful to disable this property when using EXPLAIN in order to make the query plan easier to read.
optimizer.optimize-metadata-queries
Type:
boolean
Default value:
false
Enable optimization of some aggregations by using values that are stored as metadata. This allows Presto to execute some simple queries in constant time. Currently, this optimization applies to max
, min
and approx_distinct
of partition keys and other aggregation insensitive to the cardinality of the input (including DISTINCT
aggregates). Using this may speed up some queries significantly.
The main drawback is that it can produce incorrect results if the connector returns partition keys for partitions that have no rows. In particular, the Hive connector can return empty partitions if they were created by other systems (Presto cannot create them).
optimizer.optimize-single-distinct
Type:
boolean
Default value:
true
The single distinct optimization will try to replace multiple DISTINCT
clauses with a single GROUP BY
clause, which can be substantially faster to execute.
optimizer.push-aggregation-through-join
Type:
boolean
Default value:
true
When an aggregation is above an outer join and all columns from the outer side of the join are in the grouping clause, the aggregation is pushed below the outer join. This optimization is particularly useful for correlated scalar subqueries, which get rewritten to an aggregation over an outer join. For example:
SELECT * FROM item i
WHERE i.i_current_price > (
SELECT AVG(j.i_current_price) FROM item j
WHERE i.i_category = j.i_category);
Enabling this optimization can substantially speed up queries by reducing the amount of data that needs to be processed by the join. However, it may slow down some queries that have very selective joins. This can also be specified on a per-query basis using the push_aggregation_through_join
session property.
optimizer.push-table-write-through-union
Type:
boolean
Default value:
true
Parallelize writes when using UNION ALL
in queries that write data. This improves the speed of writing output tables in UNION ALL
queries because these writes do not require additional synchronization when collecting results. Enabling this optimization can improve UNION ALL
speed when write speed is not yet saturated. However, it may slow down queries in an already heavily loaded system. This can also be specified on a per-query basis using the push_table_write_through_union
session property.
optimizer.join-reordering-strategy
Type:
string
Allowed values:
AUTOMATIC
,ELIMINATE_CROSS_JOINS
,NONE
Default value:
AUTOMATIC
The join reordering strategy to use. NONE
maintains the order the tables are listed in the query. ELIMINATE_CROSS_JOINS
reorders joins to eliminate cross joins where possible and otherwise maintains the original query order. When reordering joins it also strives to maintain the original table order as much as possible. AUTOMATIC
enumerates possible orders and uses statistics-based cost estimation to determine the least cost order. If stats are not available or if for any reason a cost could not be computed, the ELIMINATE_CROSS_JOINS
strategy is used. This can also be specified on a per-query basis using the join_reordering_strategy
session property.
optimizer.max-reordered-joins
Type:
integer
Default value:
9
When optimizer.join-reordering-strategy is set to cost-based, this property determines the maximum number of joins that can be reordered at once.
Warning
The number of possible join orders scales factorially with the number of relations, so increasing this value can cause serious performance issues.
optimizer.use-defaults-for-correlated-aggregation-pushdown-through-outer-joins
Type:
boolean
Default value:
true
Aggregations can sometimes be pushed below outer joins (see optimizer.push-aggregation-through-join). In general, aggregate functions have custom null-handling behavior. In order to correctly process the null padded rows that may be produced by the outer join, the optimizer introduces a subsequent cross join with corresponding aggregations over a single null value and then coalesces the aggregations from the join output with these null aggregated values.
For certain aggregate functions (those that ignore nulls, COUNT
, etc) the cross join may be avoided and the default/known aggregate value over NULL
may be coalesced directly with the aggregate outputs of the join. This optimization eliminates the cross join, may convert the outer join into an inner join and thereby produces more optimal plans.
optimizer.rewrite-expression-with-constant-variable
Type:
boolean
Default value:
true
Extract expressions which have constant value from filter and assignment expressions, and replace the expressions with constant value.
optimizer.history-based-optimizer-plan-canonicalization-strategies
Type:
string
Default value:
IGNORE_SAFE_CONSTANTS
Plan canonicalization strategies used to canonicalize a query plan for history based optimization.
optimizer.track-history-stats-from-failed-queries
Type:
boolean
Default value:
true
Track history based plan statistics from complete plan fragments in failed queries.
optimizer.log-plans-used-in-history-based-optimizer
Type:
boolean
Default value:
false
Log the stats equivalent plan and canonicalized plans used in history based optimization.
optimizer.exploit-constraints
Type:
boolean
Default value:
true
Enable analysis and propagation of logical properties like distinct keys or cardinality among the nodes of a query plan. The optimizer may then use these properties to perform various optimizations.
optimizer.confidence-based-broadcast
Type:
boolean
Default value:
false
Enable broadcasting based on the confidence of the statistics that are being used, by broadcasting the side of a joinNode which has the highest (HIGH
or FACT
) confidence statistics. If both sides have the same confidence statistics, then the original behavior will be followed. This can also be specified on a per-query basis using the confidence_based_broadcast
session property.
optimizer.treat-low-confidence-zero-estimation-as-unknown
Type:
boolean
Default value:
false
Enable treating LOW
confidence, zero estimations as UNKNOWN
during joins. This can also be specified on a per-query basis using the treat-low-confidence-zero-estimation-as-unknown
session property.
optimizer.retry-query-with-history-based-optimization
Type:
boolean
Default value:
false
Enable retry for failed queries who can potentially be helped by HBO. This can also be specified on a per-query basis using the retry-query-with-history-based-optimization
session property.
Planner Properties
planner.query-analyzer-timeout
Type:
duration
Default value:
3m
Maximum running time for the query analyzer in case the processing takes too long or is stuck in an infinite loop. When timeout expires the planner thread is interrupted and throws exception.
Regular Expression Function Properties
The following properties allow tuning the Regular Expression Functions.
regex-library
Type:
string
Allowed values:
JONI
,RE2J
Default value:
JONI
Which library to use for regular expression functions. JONI
is generally faster for common usage, but can require exponential time for certain expression patterns. RE2J
uses a different algorithm which guarantees linear time, but is often slower.
re2j.dfa-states-limit
Type:
integer
Minimum value:
2
Default value:
2147483647
The maximum number of states to use when RE2J builds the fast but potentially memory intensive deterministic finite automaton (DFA) for regular expression matching. If the limit is reached, RE2J will fall back to the algorithm that uses the slower, but less memory intensive non-deterministic finite automaton (NFA). Decreasing this value decreases the maximum memory footprint of a regular expression search at the cost of speed.
re2j.dfa-retries
Type:
integer
Minimum value:
0
Default value:
5
The number of times that RE2J will retry the DFA algorithm when it reaches a states limit before using the slower, but less memory intensive NFA algorithm for all future inputs for that search. If hitting the limit for a given input row is likely to be an outlier, you want to be able to process subsequent rows using the faster DFA algorithm. If you are likely to hit the limit on matches for subsequent rows as well, you want to use the correct algorithm from the beginning so as not to waste time and resources. The more rows you are processing, the larger this value should be.
Logging Properties
log.max-history
Type:
integer
Default value:
30
The log.max-history
property controls the number of archive log periods that the application retains. In Presto, one log period corresponds to one day. For instance, if log.max-history
is set to 30, the system will keep logs for the past 30 days.
log.max-size
Type:
data size
Default value:
100MB
The maximum file size for the general application log file.
http-server.log.enabled
Type:
boolean
Default value:
true
Flag to enable or disable logging for the HTTP server.
http-server.log.compression.enabled
Type:
boolean
Default value:
true
Flag to enable or disable compression of the log files of the HTTP server.
http-server.log.path
Type:
string
Default value:
var/log/http-request.log
The path to the log file used by the HTTP server. The path is relative to the data directory, configured by the launcher script as detailed in Running Presto.
http-server.log.max-history
Type:
integer
Default value:
15
The http-server.log.max-history
property controls the number of archive log periods that the HTTP server retains. In Presto, one log period corresponds to one day. For instance, if http-server.log.max-history
is set to 15, the system will keep logs for the past 15 days.
http-server.log.max-size
Type:
data size
Default value:
100MB
The maximum file size for the log file of the HTTP server.
Legacy Compatible Properties
legacy_json_cast
Type:
boolean
Default value:
true
When casting from JSON
to ROW
, ignore the case of field names in RowType
for legacy support so that the matching is case-insensitive. Set legacy_json_cast
to false
to strictly enforce the case-sensitivity of double quoted field names in RowType
when matching. Matching for unquoted field names remains case-insensitive.