PostgreSQL settings

For Managed Service for PostgreSQL clusters, you can configure PostgreSQL settings. Some settings are configured at the cluster level, while others, at the user level.

The label next to the setting name shows which interface can be used to set the value of this setting: the management console, CLI, API, or Terraform. The All interfaces label means that all of the above interfaces are supported.

Depending on the selected interface, the same setting may be represented in a different way, e.g.:

• Backend flush after in the management console is the same as:
  • backend_flush_after in the gRPC API, CLI, and Terraform.
  • backendFlushAfter in the REST API.
• Default transaction isolation in the user-level settings in the management console is the same as:
  • --default-transaction-isolation in the CLI.
  • default_transaction_isolation in the gRPC API.
  • defaultTransactionIsolation in the REST API.

Settings dependency on the host class and storage sizeSettings dependency on the host class and storage size

The values of some PostgreSQL settings can be automatically adjusted when you change the host class or storage size:

• If the values were not specified or are not suitable for the new class or size, the default settings for this class or size will be applied.
• If the settings you specified manually are suitable for the new class or size, they will not change.

The settings that depend on the host class are:

• Autovacuum max workers.
• Autovacuum vacuum cost delay.
• Autovacuum vacuum cost limit.
• Conn limit.
• Max connections.
• Shared buffers.

The settings that depend on the storage size are:

• Max wal size
• Min wal size

Cluster-level settingsCluster-level settings

You can use the following settings at the cluster level:

• Archive timeout All interfaces

  Period (in milliseconds) for archiving the PostgreSQL transaction log.

  The minimum value is 10000, the maximum one is 86400000. The default value is 30000.

  For more information, see the PostgreSQL documentation.

• Array nulls All interfaces

  Used to manage recognition of NULL elements when inserting an array. If this setting is enabled, these elements are recognized as a NULL field. Otherwise, they are recognized as a string containing the word NULL.

  This setting is enabled by default.

  For more information, see the PostgreSQL documentation.

• Auto explain log analyze Management console API Terraform

  Determines whether to automatically output query plan statistics to the PostgreSQL log without having to run EXPLAIN manually. This allows you to track unoptimized queries. This setting uses the auto_explain module. To enable it, connect the auto_explain library.

  It is disabled by default (query plan statistics are not logged).

  For more information, see the PostgreSQL documentation.

• Auto explain log buffers Management console API Terraform

  Determines whether to output buffer usage statistics to the PostgreSQL log using the auto_explain module. Similar to the BUFFERS parameter in the EXPLAIN command. Applies only when Auto explain log analyze is enabled.

  This setting is disabled by default (buffer usage statistics are not logged).

  For more information, see the PostgreSQL documentation.

• Auto explain log min duration Management console API Terraform

  The minimum query execution time (in milliseconds) when logging is enabled in the auto_explain module.

  The minimum value is -1 (logging disabled), while the maximum one is 2147483647. The default value is -1. When the value is 0, execution plans for all queries are logged regardless of their execution time.

  For more information, see the PostgreSQL documentation.

• Auto explain log nested statements Management console API Terraform

  Determines whether the auto_explain module will log the execution of nested queries inside SQL functions. Applies only when Auto explain log analyze is enabled.

  This setting is disabled by default (execution plans are logged for top-level statements).

  For more information, see the PostgreSQL documentation.

• Auto explain log timing Management console API Terraform

  Determines whether the auto_explain module will log timing information for individual query execution plan steps. Similar to the TIMING parameter in the EXPLAIN command. Applies only when Auto explain log analyze is enabled.

  This setting is disabled by default (timing information for individual steps is not logged).

  For more information, see the PostgreSQL documentation.

• Auto explain log triggers Management console API Terraform

  Determines whether to output trigger execution statistics in the auto_explain module. Applies only when Auto explain log analyze is enabled.

  This setting is disabled by default (trigger execution statistics are not output).

  For more information, see the PostgreSQL documentation.

• Auto explain log verbose Management console API Terraform

  Determines whether to provide log details in the auto_explain module. Similar to the VERBOSE parameter in the EXPLAIN command. Applies only when Auto explain log analyze is enabled.

  This setting is disabled by default (no logging details).

  For more information, see the PostgreSQL documentation.

• Auto explain sample rate Management console API Terraform

  Percentage of queries logged per session using the auto_explain module. Applies only when Auto explain log analyze is enabled.

  The minimum value is 0.0 (no queries are logged), while the maximum one is 1.0 (all queries are logged). The default value is 1.0.

  For more information, see the PostgreSQL documentation.

• Autovacuum analyze scale factor All interfaces

  Percentage of changed or deleted records in the table that, when reached, triggers autovacuum to start the ANALYZE statistics collection command.

  The minimum value is 0.0, while the maximum one is 1.0. The default value is 0.0001.

  For more information, see the PostgreSQL documentation.

• Autovacuum max workers Management console API Terraform CLI

  The maximum number of autovacuum worker processes running in parallel. Autovacuuming runs on for each DB a regular basis, determines the table records marked for deletion, and deletes them.

  The minimum value is 1, while the maximum one is 32. The default value depends on the selected host class and is equal to the number of vCPUs on a single host, with a minimum of 3.

  For more information, see the PostgreSQL documentation.

• Autovacuum naptime Management console API Terraform

  Sets the minimum interval (in milliseconds) between autovacuums. If your data changes frequently, you can increase this interval to avoid overloading your database.

  The minimum value is 1000, while the maximum one is 86400000. The default value is 15000.

  For more information, see the PostgreSQL documentation.

• Autovacuum vacuum cost delay All interfaces

  The amount of time (in milliseconds) for the autovacuum process to sleep when the cost limit has been exceeded.

  The minimum value is -1 (the setting is not applied), while the maximum one is 100. The default value depends on the selected host class.

  • If the number of vCPUs for the selected host class is 10 or more, the value is set to 5.

  • In other cases, the default value is calculated using the following formula:

    55 - 5 × <number_of_vCPUs_per_host>
    

  For more information, see the PostgreSQL documentation.

• Autovacuum vacuum cost limit All interfaces

  The cost limit that, when exceeded, will freeze the autovacuum process for the time specified by the Autovacuum vacuum cost delay parameter.

  The minimum value is -1 (the setting is not applied), while the maximum one is 10000. The default value depends on the selected host class and is determined by the formula:

  150 × <number_of_vCPUs_per_host> + 400
  

  For example:

  Host class	vCPU	Default value
  s2.small	4	150 × 4 + 400 = 1000
  m2.medium	6	150 × 6 + 400 = 1300

  For more information, see the PostgreSQL documentation.

• Autovacuum vacuum insert scale factor All interfaces

  Percentage of the table size added to the Autovacuum vacuum insert threshold value that, when reached, triggers the autovacuum process.

  The minimum value is 0.0, while the maximum one is 1.0. The default value is 0.2.

  For more information, see the PostgreSQL documentation.

• Autovacuum vacuum insert threshold All interfaces

  Sets the number of rows that, when inserted into a table, triggers the autovacuum process.

  The minimum value is -1 (the setting is not applied), while the maximum one is 2147483647. The default value is 1000.

  For more information, see the PostgreSQL documentation.

• Autovacuum vacuum scale factor All interfaces

  Percentage of changed or deleted records in the table that, when reached, triggers autovacuum to start the VACUUM cleaning command.

  The minimum value is 0.0 (the setting is not applied), while the maximum one is 1.0. The default value is 0.00001.

  For more information, see the PostgreSQL documentation.

• Autovacuum work mem Management console API Terraform CLI

  The amount of memory (in bytes) allocated to each autovacuum process.

  The minimum value is -1 (the setting is not applied), while the maximum one is 2147483647. The default value is -1.

  For more information, see the PostgreSQL documentation.

• Backend flush after All interfaces

  The maximum amount of data (in kilobytes) that a utility process can write to the OS kernel's page cache. If it is exceeded, the DBMS commands the OS to flush data to the disk. The higher the parameter, the less likely a slowdown is when flushing data to the disk using fsync (for example, on completing a checkpoint).

  The minimum value is 0 (the setting is not applied), while the maximum one is 2048. The default value is 0.

  For more information, see the PostgreSQL documentation.

• Backslash quote All interfaces

  Controls representation of quotation mark in an SQL string.

  Acceptable values include:

  • backslash_quote (BACKSLASH_QUOTE for Terraform, API, and CLI): Quotation marks can be represented as \' (equivalent to on).
  • on (BACKSLASH_QUOTE_ON for Terraform, API, and CLI): Quotation marks can be represented as \'.
  • off (BACKSLASH_QUOTE_OFF for Terraform, API, and CLI): Quotation marks may only be used in the usual SQL way ('').
  • safe_encoding (BACKSLASH_QUOTE_SAFE_ENCODING for Terraform, API, and CLI): Quotation marks may be represented as \' only for the client encodings that do not use \ in multi-byte characters.

  The default value is safe_encoding.

  For more information, see the PostgreSQL documentation.

• Bgwriter delay All interfaces

  Time to sleep (in milliseconds) after running the background writer. This process writes new or changed items from the PostgreSQL buffer to the disk. The delay helps avoid rewriting the same page many times for every page modification and reduce IO load.

  The minimum value is 10, while the maximum one is 10000. The default value is 200.

  For more information, see the PostgreSQL documentation.

• Bgwriter flush after Management console API Terraform

  Limits the amount of data processed by the background writer (in kilobytes). When the limit is exceeded, the DBMS instructs the OS to flush this data to disk. This parameter limits the amount of dirty data in the kernel's page cache, reducing the likelihood of stalls when an fsync command is issued when the checkpoint is complete, or when the OS writes the data to the disk in the background.

  The minimum value is 0, while the maximum one is 2048. The default value is 512.

  For more information, see the PostgreSQL documentation.

• Bgwriter lru maxpages All interfaces

  Maximum number of PostgreSQL buffers that can be written by the background writer per activity round. The value of zero disables background writing.

  The minimum value is 0, while the maximum one is 1073741823. The default value is 100.

  For more information, see the PostgreSQL documentation.

• Bgwriter lru multiplier All interfaces

  Multiplies the average need in buffers over the previous rounds to calculate the background writer's buffer need for the next round.

  The minimum value is 0, while the maximum one is 10. The default value is 2.

  For more information, see the PostgreSQL documentation.

• Bytea output All interfaces

  Sets the output format for binary string values (the bytea type):

  • hex (BYTEA_OUTPUT_HEX for Terraform, API, and CLI) encodes binary data as two hexadecimal digits per byte, for example, 'SELECT '\xDEADBEEF';'.
  • escape (BYTEA_OUTPUT_ESCAPE for Terraform, API, and CLI) means the standard PostgreSQL format (ASCII characters only).

  The default value is hex.

  For more information, see the PostgreSQL documentation.

• Checkpoint completion target All interfaces

  A fraction of the checkpoint interval that defines the maximum length of issuing a checkpoint. For example, if the value is 0.5, the system will try to complete the checkpoint in about half the interval before the next checkpoint is issued.

  The minimum value is 0.0, while the maximum one is 1.0. The default value is 0.5.

  For more information, see the PostgreSQL documentation.

• Checkpoint flush after Management console API Terraform

  Size of page cache (in kilobytes) that triggers data flush at a checkpoint. The pages beyond the value are flushed to the disk and deleted from the OS page cache.

  The minimum value is 0, while the maximum one is 2048. The default value is 256.

  For more information, see the PostgreSQL documentation.

• Checkpoint timeout All interfaces

  The interval between checkpoints (in milliseconds).

  The minimum value is 30 000, while the maximum one is 86400000. The default value is 300 000.

  For more information, see the PostgreSQL documentation.

• Client connection check interval Management console API CLI

  Client connection check interval when executing queries (in milliseconds). The check polls the server socket for a connection and aborts long-running queries if it detects that the connection has been terminated. PostgreSQL supports this feature starting from version 14.

  The minimum value is 0 (no check is run), while the maximum one is 2147483647. By default, the minimum value is used.

  For more information, see the PostgreSQL documentation.

• Client min messages All interfaces

  The level of logging messages sent to client applications. Acceptable values (in ascending order of severity): debug5, debug4, debug3, debug2, debug1, info, notice, warning, error, log, fatal, and panic (for Terraform, API, CLI LOG_LEVEL_DEBUG5, LOG_LEVEL_DEBUG4, LOG_LEVEL_DEBUG3, LOG_LEVEL_DEBUG2, LOG_LEVEL_DEBUG1, LOG_LEVEL_INFO, LOG_LEVEL_NOTICE, LOG_LEVEL_WARNING, LOG_LEVEL_ERROR, LOG_LEVEL_LOG, LOG_LEVEL_FATAL, and LOG_LEVEL_PANIC).

  The default value is NOTICE.

  For more information, see the PostgreSQL documentation.

• Constraint exclusion All interfaces

  Allows the query planner to use table constraints to optimize queries.

  Acceptable values include:

  • on (CONSTRAINT_EXCLUSION_ON for Terraform, API, and CLI): Use constraints for all tables.
  • off (CONSTRAINT_EXCLUSION_OFF for Terraform, API, and CLI): Do not use constraints.
  • partition (CONSTRAINT_EXCLUSION_PARTITION for Terraform, API, and CLI): Only use constraints for child tables and UNION ALL clauses.

  The default value is partition.

  For more information, see the PostgreSQL documentation.

• Cursor tuple fraction All interfaces

  Sets the planner's estimate of the fraction of rows to be retrieved via a cursor.

  The minimum value is 0.0, while the maximum one is 1.0. The default value is 0.1.

  For more information, see the PostgreSQL documentation.

• Deadlock timeout Management console API Terraform CLI

  Waiting time (in milliseconds) before checking for a deadlock condition.

  The minimum value is 1, while the maximum one is 2147483647. The default value is 1000.

  For more information, see the PostgreSQL documentation.

• Default statistics target All interfaces

  The maximum number of statistics records for each DB table column. The query planner uses statistics to estimate the number of rows returned by queries to select the most suitable query plan.

  To improve the quality of the planner's estimates, increase the target.

  The minimum value is 1, while the maximum one is 10000. The default value is 1000.

  For more information, see the PostgreSQL documentation.

• Default transaction isolation All interfaces

  This setting determines the default isolation level to be used for new SQL transactions.

  Acceptable values include:

  • read committed (TRANSACTION_ISOLATION_READ_COMMITTED for Terraform, API, and CLI): The query only sees the rows that were committed before it started.
  • read uncommitted (TRANSACTION_ISOLATION_READ_UNCOMMITTED for Terraform, API, and CLI): The behavior of this isolation level in PostgreSQL is identical to read committed.
  • repeatable read (TRANSACTION_ISOLATION_REPEATABLE_READ for Terraform, API, and CLI): All queries in the current transaction only see the rows that were committed before the first query to select or update data in this transaction.
  • serializable (TRANSACTION_ISOLATION_SERIALIZABLE for Terraform, API, and CLI): The strictest isolation level of all those mentioned. The behavior of this isolation level in PostgreSQL is identical to repeatable read. However, if the overlap of read and write operations of parallel serializable transactions is incompatible with their serial execution, one of the transactions is rolled back with the serialization failure error.

  The default value is read committed.

  To learn more about isolation levels, see the PostgreSQL documentation.

  The setting applies at the Managed Service for PostgreSQL cluster level, but it can be overridden at the user level.

• Default transaction read only All interfaces

  Sets the read only mode in each new transaction for any tables except temporary ones.

  This setting is disabled by default (both reads and writes are allowed).

  For more information, see the PostgreSQL documentation.

• Default with oids All interfaces

  Adds an OID column containing a unique row ID. The setting has effect if the table is created:

  • Without specifying WITH OIDS or WITHOUT OIDS.
  • Using the SELECT INTO command.

  Using OID is considered deprecated in user tables, so enable this setting for backward compatibility reasons only.

  Disabled by default (no OID column is added).

  For more information, see the PostgreSQL documentation.

• Effective cache size All interfaces

  Sets the assumption about the effective size of the disk cache that is available to a single query. With a higher value, index scans are more likely to be used by the query planner. With a lower value, sequential scans are more likely.

  The minimum value is 0, while the maximum one is 549755813888 (512 GB). The default value is 107374182400 (100 GB).

  For more information, see the PostgreSQL documentation.

• Effective io concurrency All interfaces

  The number of concurrent disk I/O operations for an individual DB session. The higher this number, the more operations PostgreSQL will attempt to initiate in parallel within a session.

  The minimum value is 0, while the maximum one is 1000. The default value is 1.

  For more information, see the PostgreSQL documentation.

• Enable async append Management console API CLI

  Allows the query planner to consider asynchronous execution of the query plan on different hosts when adding data from external sources. PostgreSQL supports this feature starting from version 14.

  This setting is enabled by default.

  For more information, see the PostgreSQL documentation.

• Enable bitmapscan All interfaces

  Allows the query planner to use the bitmap-scan plan types, even if this is not specified in the query explicitly. This access method is similar to regular access by index, but occurs in two steps:

  1. The index is scanned (Bitmap Index Scan) and a bitmap is built where the rows to be read by the query are flagged.

  2. The table is scanned (Bitmap Heap Scan). Note that:

     • The pages are read sequentially (this increases the likelihood of using the OS cache).
     • Each page is viewed only once.

  The setting is effective when repeating queries to tables.

  This setting is enabled by default.

  For more information, see the PostgreSQL documentation.

• Enable gathermerge Management console API CLI

  Allows the query planner to use a Gather Merge node for merging query execution results while preserving their order in the parallel query plan. PostgreSQL supports this feature starting from version 14.

  This setting is enabled by default.

  For more information, see the PostgreSQL documentation.

• Enable hashagg All interfaces

  Allows the planner to build a hash table from the result set, even if this is not specified in the query explicitly. This setting is effective for frequent unsorted queries to large database tables.

  This setting is enabled by default.

  For more information, see the PostgreSQL documentation.

• Enable hashjoin All interfaces

  Allows the scheduler to JOIN tables using the row hash values, even if this is not specified in the query explicitly. This setting is effective when handling large amounts of data or when the tables are not sorted by the join columns.

  This setting is enabled by default.

  For more information, see the PostgreSQL documentation.

• Enable incremental sort All interfaces

  Allows the query planner to use incremental sorting. This type of sorting can reduce query execution time and RAM requirements if rows need to be sorted by multiple columns, and one or more of them have already been sorted. PostgreSQL supports this feature starting from version 13.

  This setting is enabled by default.

  For more information, see the PostgreSQL documentation.

• Enable indexonlyscan All interfaces

  Allows the query planner to use a table index without accessing the data, even if this is not specified in the query explicitly.

  This setting is enabled by default.

  For more information, see the PostgreSQL documentation.

• Enable indexscan All interfaces

  Allows the query planner to use a table index, even if this is not explicitly specified in the query.

  This setting is enabled by default.

  For more information, see the PostgreSQL documentation.

• Enable material All interfaces

  Allows the query planner to use materialization.

  This setting is enabled by default.

  For more information, see the PostgreSQL documentation.

• Enable mergejoin All interfaces

  Allows the query planner to merge JOIN operations with tables.

  This setting is enabled by default.

  For more information, see the PostgreSQL documentation.

• Enable nestloop All interfaces

  Allows the query planner to use JOIN with nested loops. When the setting is disabled, the query planner will use other methods.

  This setting is enabled by default.

  For more information, see the PostgreSQL documentation.

• Enable parallel append All interfaces

  Allows the query planner to use parallel-aware append.

  This setting is enabled by default.

  For more information, see the PostgreSQL documentation.

• Enable parallel hash All interfaces

  Allows the query planner to use hash-join with parallel hash. The setting only applies when Enable hashjoin is enabled.

  This setting is enabled by default.

  For more information, see the PostgreSQL documentation.

• Enable partition pruning All interfaces

  Allows the query planner to remove unneeded partitions from the query plans for partitioned tables.

  This setting is enabled by default.

  For more information, see the PostgreSQL documentation.

• Enable partitionwise aggregate All interfaces

  Allows the query planner to perform grouping or aggregation on partitioned tables separately for each partition.

  This setting is disabled by default (query planner ignores partitions).

  For more information, see the PostgreSQL documentation.

• Enable partitionwise join All interfaces

  Allows the query planner to plan queries partitionwise. The setting lets you join partitioned tables by joining their matching partitions.

  This setting is disabled by default (query planner ignores partitions).

  For more information, see the PostgreSQL documentation.

• Enable seqscan All interfaces

  Allows the query planner to use sequential table scan plans.

  This setting is enabled by default.

  For more information, see the PostgreSQL documentation.

• Enable sort All interfaces

  Allows the query planner to use explicit sort steps.

  This setting is enabled by default.

  For more information, see the PostgreSQL documentation.

• Enable tidscan All interfaces

  Allows the query planner to use TID (tuple identifier) scan plans to speed up queries.

  This setting is enabled by default (the planner uses TID scans).

  For more information, see the PostgreSQL documentation.

• Escape string warning All interfaces

  A warning is issued if a backslash (\) appears in a regular string constant ('...' syntax). Only applies if Standard conforming strings is off.

  This setting is enabled by default.

  For more information, see the PostgreSQL documentation.

• Exit on error All interfaces

  Enables session interruption in case of any error in the query.

  This setting is disabled by default.

  For more information, see the PostgreSQL documentation.

• Force parallel mode All interfaces

  Allows executing queries in parallel mode for testing purposes:

  • off (FORCE_PARALLEL_MODE_OFF for Terraform, API, and CLI): Use parallel mode only when performance increase is expected.
  • on (FORCE_PARALLEL_MODE_ON for Terraform, API, and CLI): Force parallelize all the queries where it is safe.
  • regress (FORCE_PARALLEL_MODE_REGRESS for Terraform, API, and CLI): Equivalent to on, but the standard output is the same as when using off.

  The default value is off.

  For more information, see the PostgreSQL documentation.

• From collapse limit All interfaces

  Maximum number of items in the FROM list. As long as this number is not exceeded, the query planner will merge nested queries with upper queries. You can decrease planning time using smaller values, but your query plan might get less effective.

  The minimum value is 1, while the maximum one is 2147483647. The default value is 8.

  For more information, see the PostgreSQL documentation.

• Geqo Management console API

  Enables genetic query optimization (GEQO).

  Default value: false (genetic optimization is disabled).

  For more information, see the PostgreSQL documentation.

• Geqo effort Management console API

  Used in the GEQO algorithm to set the ratio between the time allotted for query planning and quality of the query execution plan.

  The higher is the value, the longer it takes to plan the query. However, the probability of selecting an efficient query execution plan increases. This setting does not affect the algorithm operation directly but is used to calculate default values for other settings.

  The minimum value is 1, while the maximum one is 10. The default value is 5.

  For more information, see the PostgreSQL documentation.

• Geqo generations Management console API

  Sets the number of iterations for the GEQO algorithm.

  Useful values are in the range between 100 and 1000.

  If the value of the setting is 0 (default), the number of algorithm iterations is selected based on the Geqo pool size setting.

  For more information, see the PostgreSQL documentation.

• Geqo pool size Management console API

  Sets the number of species in the GEQO algorithm's genetic population.

  Cannot be equal to 1. Useful values are in the range between 100 and 1000.

  If the setting is 0 (default), the number of species is selected depending on the Geqo effort setting and the number of tables in the query.

  For more information, see the PostgreSQL documentation.

• Geqo seed Management console API

  Sets an initial value for the random number generator used by the GEQO algorithm to select paths in the join sequence search space.

  When you change the setting, you alter the set of join paths examined which might either improve or degrade the resulting path.

  The minimum value is 0, while the maximum one is 1. The default value is 0.

  For more information, see the PostgreSQL documentation.

• Geqo selection bias Management console API

  Sets the selective pressure within the GEQO population.

  The minimum value is 1.50, while the maximum one is 2.00. The default value is 2.00.

  For more information, see the PostgreSQL documentation.

• Geqo threshold Management console API

  The GEQO algorithm will only be used to plan such queries where the number of tables in the FROM clause is equal to or greater than this setting.

  For small queries, we recommend the standard planner that uses full scan. However, for the queries across many tables, a full scan might take more time than a suboptimal plan.

  The minimum value is 2, while the maximum one is 2147483647. The default value is 12.

  For more information, see the PostgreSQL documentation.

• Gin pending list limit All interfaces

  Sets the maximum size of a GIN index's pending list in bytes. The pending list is used when fastupdate mode is enabled. If the pending list exceeds the specified limit, its entries are moved to the index's main GIN data structure in bulk and the list is cleared.

  The minimum value is 64, while the maximum one is 2147483647 (2 GB). The default value is 4194304.

  For more information, see the PostgreSQL documentation.

• Hash mem multiplier Management console API Terraform

  Defines the maximum amount of memory that operations with hash tables can use The amount is calculated by multiplying the setting value by Work mem.

  The minimum value is 0.0, while the maximum one is 1000.0. The default value is 1.0.

  For more information, see the PostgreSQL documentation.

• Idle in transaction session timeout All interfaces

  The maximum idle time of an open transaction (in milliseconds). When exceeded, the session running this transaction terminates.

  The minimum value is 0, while the maximum one is 2147483647. The default value is 0.

  For more information, see the PostgreSQL documentation.

• Jit Management console API Terraform

  Enables Just-in-Time (JIT) compilation of queries for PostgreSQL. If this setting is enabled, SQL queries are compiled into machine code directly at runtime. This will speed up execution of complex CPU-intensive queries.

  This setting is disabled by default.

  For more information, see the PostgreSQL documentation.

• Join collapse limit All interfaces

  Maximum number of items in the FROM list. As long as this value is not exceeded, the planner will move explicit JOIN constructs (except FULL JOINs) to the list. You can decrease planning time using smaller values, but your query plan might get less effective.

  The minimum value is 1, while the maximum one is 2147483647. The default value is 8.

  For more information, see the PostgreSQL documentation.

• Lo compat privileges Management console API CLI Terraform

  Disables access permission check for large objects. Prior to version 9.0, large objects were not covered by access permissions, so any user could access them for reading and writing. Enable this setting if you need compatibility with PostgreSQL versions below 9.0.

  The setting is disabled by default (privilege checks are enabled).

  For more information, see the PostgreSQL documentation.

• Lock timeout All interfaces

  Specifies how long to wait for the lock to be released (in milliseconds). Locks can be used for tables, indexes, rows, and other database objects. If the timeout for an operation has expired, the operation is aborted.

  The minimum value is 0 (timeout is off, lock waiting time can be indefinite), the maximum one is 2147483647. The default value is 1000.

  For more information, see the PostgreSQL documentation.

  The setting applies at the Managed Service for PostgreSQL cluster level, but it can be overridden at the user level.

• Log checkpoints All interfaces

  Enables logging of checkpoints and server restart points.

  The setting is disabled by default (no logging).

  For more information, see the PostgreSQL documentation.

• Log connections Management console API CLI Terraform

  Enables logging of all attempts to connect to the PostgreSQL server, including those where clients were successfully authenticated.

  The setting is disabled by default (no logging).

  For more information, see the PostgreSQL documentation.

• Log disconnections Management console API CLI Terraform

  Enables logging of session terminations.

  The setting is disabled by default (no logging).

  For more information, see the PostgreSQL documentation.

• Log duration Management console API CLI Terraform

  Enables logging of the duration of each completed statement.

  The setting is disabled by default (no logging).

  For more information, see the PostgreSQL documentation.

• Log error verbosity Management console API CLI Terraform

  Sets the level of detail for the PostgreSQL log entry per message. Log detail levels in ascending order of verbosity:

  • terse (LOG_ERROR_VERBOSITY_TERSE for Terraform, CLI, and API). The DETAIL, HINT, QUERY, and CONTEXT fields are excluded from the error message.
  • default (LOG_ERROR_VERBOSITY_DEFAULT for Terraform, CLI, and API). Default.
  • verbose (LOG_ERROR_VERBOSITY_VERBOSE for Terraform, CLI, and API). The error message includes the SQLSTATE error code, the source code file name, function name, and line number that generated the error.

  For more information, see the PostgreSQL documentation.

• Log lock waits Management console API CLI Terraform

  Controls logging of long lock waits. When enabled, a log entry is created when a PostgreSQL session waits longer than Deadlock timeout to get a lock.

  This setting is disabled by default.

  For more information, see the PostgreSQL documentation.

• Log min duration sample Management console API Terraform

  The setting is similar to Log min duration statement, but only applies to the statements listed in Log statement sample rate.

  When the value is 0, the duration is logged for all the specified statements.

  The minimum value is -1 (disables logging of the statement duration), while the maximum one is 2147483647. The default value is -1.

  For more information, see the PostgreSQL documentation.

• Log min duration statement Management console API CLI Terraform

  Sets the threshold for statement duration logging (in milliseconds).

  When the value is 0, the duration is logged for all the specified statements.

  The minimum value is -1 (disables duration logging), while the maximum one is 2147483647. The default value is -1.

  For more information, see the PostgreSQL documentation.

  The setting applies at the Managed Service for PostgreSQL cluster level, but it can be overridden at the user level.

• Log min error statement Management console API CLI Terraform

  Defines the logging level for errors of SQL statement execution. A message about statement execution is logged if it at least has the specified severity level. Acceptable values: DEBUG5, DEBUG4, DEBUG3, DEBUG2, DEBUG1, INFO, NOTICE, WARNING, ERROR, LOG, FATAL, and PANIC.

  The default value is ERROR. This means that the PostgreSQL log will include all the statements that ended with a message having the ERROR, LOG, FATAL, and PANIC severity level.

  To disable logging of most failed statements, select the PANIC value.

  For more information, see the PostgreSQL documentation.

• Log min messages Management console API CLI Terraform

  Defines the logging level in PostgreSQL. All messages of the selected severity level (or higher) are logged. Acceptable values (in ascending severity): DEBUG5, DEBUG4, DEBUG3, DEBUG2, DEBUG1, INFO, NOTICE, WARNING, ERROR, LOG, FATAL , and PANIC.

  The default value is WARNING. This means that the PostgreSQL log will include all the messages with the WARNING, ERROR, LOG, FATAL, and PANIC severity level.

  To disable logging of most messages, select the PANIC value.

  For more information, see the PostgreSQL documentation.

• Log parameter max length Management console API CLI Terraform

  Reduces to a specified number of bytes the value of each referenced SQL parameter that is output along with SQL operators when logging all messages except error ones.

  Logging is disabled when the value is 0.

  The minimum value is -1 (parameter values are completely logged), while the maximum one is 1073741823. By default, the minimum value is used.

  For more information, see the PostgreSQL documentation.

• Log parameter max length on error All interfaces

  Reduces to a specified number of bytes the value of each referenced SQL parameter that is output along with SQL operators when logging error messages.

  Logging is disabled when the value is 0.

  The minimum value is -1 (parameter values are completely logged), while the maximum one is 1073741823. By default, the minimum value is used.

  For more information, see the PostgreSQL documentation.

• Log recovery conflict waits Management console API CLI

  Controls logging of long recovery conflict waits when reading WAL to continue replication. When enabled, a log entry is created when a PostgreSQL session waits longer than Deadlock timeout to resolve a recovery conflict. PostgreSQL supports this feature starting from version 14.

  This setting is disabled by default.

  For more information, see the PostgreSQL documentation.

• Log statement Management console API CLI Terraform

  A filter for SQL statements to be written to the PostgreSQL log:

  • none (LOG_STATEMENT_NONE for Terraform, CLI, and API): Filter is disabled and SQL statements are not logged.
  • ddl (LOG_STATEMENT_DDL for Terraform, CLI, and API): SQL statements that allow you to change data definitions, such as CREATE, ALTER, and DROP, are logged.
  • mod (LOG_STATEMENT_MOD for Terraform, CLI, and API): All ddl statements and data-modifying statements, such as INSERT and UPDATE, are logged.
  • all (LOG_STATEMENT_ALL for Terraform, CLI, and API): All SQL statements are logged.

  The default value is none.

  For more information, see the PostgreSQL documentation.

  The setting applies at the Managed Service for PostgreSQL cluster level, but it can be overridden at the user level.

• Log statement sample rate Management console API Terraform

  The rate of SQL statements that will be logged in addition to statements logged for other reasons.

  The minimum value is 0.0, while the maximum one is 1.0. The default value is 0.0.

  For more information, see the PostgreSQL documentation.

• Log temp files Management console API CLI Terraform

  Sets the minimum size of a temporary file to be logged in PostgreSQL when deleted.

  The minimum value is -1 (information about deleted files is not logged). The maximum value is 2147483647 (2 GB). If 0, the sizes and names of all temporary files are logged. The default value is -1.

  For more information, see the PostgreSQL documentation.

• Log transaction sample rate Management console API Terraform

  The rate of transactions whose statements will be logged in addition to statements logged for other reasons.

  The minimum value is 0.0, while the maximum one is 1.0. The default value is 0.0.

  For more information, see the PostgreSQL documentation.

• Logical decoding work mem All interfaces

  The maximum amount of memory (in bytes) allocated for logical decoding before writing to a local storage. The setting limits the amount of memory used in the connection for logical replication.

  The minimum value is 65536 (64 KB), while the maximum one is 1099511627776 (1 TB). The default value is 67108864 (64 MB).

  For more information, see the PostgreSQL documentation.

• Maintenance io concurrency All interfaces

  The maximum number of concurrent disk I/O operations when maintaining PostgreSQL with the commands VACUUM, CREATE INDEX, and ALTER TABLE ADD FOREIGN KEY for an individual DB session. The higher this number, the more maintenance commands PostgreSQL will attempt to initiate in parallel within a session.

  The minimum value is 0, while the maximum one is 1000. The default value is 10.

  For more information, see the PostgreSQL documentation.

• Maintenance work mem All interfaces

  The maximum amount of memory (in bytes) to be used by PostgreSQL maintenance operations, such as VACUUM, CREATE INDEX, and ALTER TABLE ADD FOREIGN KEY. The value must be a multiple of 1024.

  The minimum value is 1048576 (1 MB), while the maximum one is 137438953472 (128 GB). The default value is 67108864 (64 MB).

  For more information, see the PostgreSQL documentation.

• Max connections Management console API CLI Terraform

  The maximum number of simultaneous connections to the PostgreSQL host.

  The minimum value is 1. The maximum and default values depend on the selected host class and are determined by the formula:

  200 × <number_of_vCPUs_per_host>
  

  Hosts with guaranteed vCPU performance under 100% (burstable) use the fixed maximum value: 200.

  By default, the maximum value is used.

  For more information, see the PostgreSQL documentation.

• Max locks per transaction Management console API CLI Terraform

  The maximum number of objects that can be locked by a single transaction. Individual transactions can lock more objects if the locks of all transactions fit in the lock table.

  The minimum value is 10, while the maximum one is 2147483647. The default value is 64.

  For more information, see the PostgreSQL documentation.

• Max logical replication workers Management console

  The maximum number of PostgreSQL logical replication workers.

  The minimum value is 4, while the maximum one is 100. By default, the minimum value is used.

  For more information, see the PostgreSQL documentation.

• Max parallel maintenance workers All interfaces

  The maximum number of parallel PostgreSQL workers that can be started by a single utility command (for example, CREATE INDEX).

  The minimum value is 0, while the maximum one is 1024. The default value is 2.

  For more information, see the PostgreSQL documentation.

• Max parallel workers All interfaces

  The maximum number of parallel PostgreSQL workers.

  The minimum value is 0, while the maximum one is 1024. The default value is 8.

  For more information, see the PostgreSQL documentation.

• Max parallel workers per gather All interfaces

  The maximum number of parallel workers that can be started by a single Gather node.

  The minimum value is 0, while the maximum one is 1024. The default value is 2.

  For more information, see the PostgreSQL documentation.

• Max pred locks per transaction Management console API CLI Terraform

  The maximum number of objects that can be locked by predicate locks per transaction. Individual transactions can lock more objects than specified in the setting if the locks of all transactions fit in the lock table.

  The minimum value is 10, while the maximum one is 2147483647 (2 GB). The default value is 64.

  For more information, see the PostgreSQL documentation.

• Max prepared transactions Management console API CLI Terraform

  The maximum number of transactions that can be in the prepared state at the same time.

  The minimum value is 0, while the maximum one is 262143. The default value is 0.

  For more information, see the PostgreSQL documentation.

• Max replication slots Management console

  The maximum number of replication slots. Replication slots automatically provide a mechanism for saving WAL (Write-Ahead Log) files until they are received by all replicas.

  The minimum value is 20, while the maximum one is 100. By default, the minimum value is used.

  For more information, see the PostgreSQL documentation.

• Max slot wal keep size Management console API Terraform

  The maximum size (in bytes) of the files of the Write-Ahead Log (WAL) stored on the master host during replication.

  The minimum value is 67108864 (64 MB). The maximum value is 50% of the storage size. The default value is -1 (unlimited). The value must be a multiple of 1024.

  For more information, see the PostgreSQL documentation.

• Max standby streaming delay All interfaces

  Waiting time (in milliseconds) after which the hot standby host replica will start canceling the queries that conflict with the about-to-be-applied WAL entries.

  The minimum value is -1 (unlimited waiting time), the maximum one is 2147483647. The default value is 30000 (30 seconds).

  For more information, see the PostgreSQL documentation.

• Max wal senders Management console

  The maximum number of concurrent connections from streaming replication source hosts.

  The minimum value is 20, while the maximum one is 100. By default, the minimum value is used.

  For more information, see the PostgreSQL documentation.

• Max wal size All interfaces

  The maximum WAL file size (in bytes) that, when reached, triggers automatic checkpoints.

  The minimum value is 2. The maximum value depends on the storage size and is equal to 10% of this value, with a maximum of 8589934592 (8 GB). By default, the maximum value is used.

  For more information, see the PostgreSQL documentation.

• Max worker processes Management console API CLI Terraform

  The maximum number of PostgreSQL background processes that can be run on the current system.

  The minimum value is 0, while the maximum one is 1024. The default value is 8.

  For more information, see the PostgreSQL documentation.

• Min wal size All interfaces

  The amount of disk space (in bytes) occupied by the WAL that, when exceeded, triggers deletion of old WAL files at checkpoints.

  The minimum value is 2. The maximum value depends on the storage size and is equal to 5% of this value, with a maximum of 1073741824 (1 GB). By default, the maximum value is used.

  For more information, see the PostgreSQL documentation.

• Old snapshot threshold Management console API CLI Terraform

  The minimum time (in milliseconds) that a query snapshot can be used without risk of an error.

  The minimum value is -1 (unlimited), while the maximum one is 86400000 (24 hours). The default value is -1.

  For more information, see the PostgreSQL documentation.

• Online analyze enable Management console API

  Enables the online_analyze module that updates statistics after the INSERT, UPDATE, DELETE, or SELECT INTO operations in the target tables.

• Operator precedence warning All interfaces

  Allows the query parser to emit a warning for any constructs that changed their behavior since version 9.4 as a result of changes in operator precedence. This feature is not supported by PostgreSQL starting from version 14.

  This setting is disabled by default.

  For more information, see the PostgreSQL documentation.

• Parallel leader participation All interfaces

  Allows the leader process to execute the query plan under Gather and Gather Merge nodes without waiting for worker processes.

  This setting is enabled by default.

  For more information, see the PostgreSQL documentation.

• Pg hint plan debug print Management console API Terraform

  Sets the level of output and detail of debugging information for the pg_hint_plan module. Only applies when Pg hint plan enable hint is enabled. Possible values (in ascending order of verbosity):

  • off (PG_HINT_PLAN_DEBUG_PRINT_OFF for Terraform and API): The output is disabled.
  • on (PG_HINT_PLAN_DEBUG_PRINT_ON for Terraform and API): Default.
  • detailed (PG_HINT_PLAN_DEBUG_PRINT_DETAILED for Terraform and API).
  • verbose (PG_HINT_PLAN_DEBUG_PRINT_VERBOSE for Terraform and API).

• Pg hint plan enable hint Management console API Terraform

  Enables the pg_hint_plan module that lets you adjust automatic execution plans using so-called hints that are simple descriptions in the SQL comments of special format.

• Pg hint plan enable hint table Management console API Terraform

  Enables the use of the hint_plan.hints table. It contains hints for the pg_hint_plan module and is used when it is not possible edit queries. The table contains the following columns:

  • id: A unique ID of the row with the hint. This column is populated automatically.
  • norm_query_string: A pattern to match the hinted queries. Replace constants with a ?. Whitespace characters are significant in the pattern.
  • application_name: The application that initiated the sessions to apply the hint to.
  • hint: A series of hints excluding surrounding comment marks.

• Pg hint plan message level Management console API Terraform

  The level of debug messages for the pg_hint_plan module that will be included in the PostgreSQL log. Only applies when Pg hint plan enable hint is enabled. The possible values include:

  • error
  • warning
  • notice
  • info (default)
  • log
  • debug

• Pg qualstats enabled Management console API CLI

  Enables the pg_qualstats module to collect statistics on predicates in WHERE operators and JOIN blocks. Used to analyze the most frequently calculated query predicates.

• Pg qualstats max Management console API CLI

  The maximum number of tracked predicates for the pg_qualstats module. Only applies when Pg qualstats enabled is enabled.

  The minimum value is 100, while the maximum one is 2147483647. The default value is 1000.

• Pg qualstats resolve oids Management console API CLI

  Enables table name recovery using OID when collecting statistics for the pg_qualstats module. The setting makes it easier to analyze data, but requires more disk space for storing statistics. Only applies when Pg qualstats enabled is enabled.

  This setting is disabled by default.

• Pg qualstats sample rate Management console API CLI

  Percentage of queries (from 0 to 1) that the pg_qualstats module collects statistics for. Only applies when Pg qualstats enabled is enabled. Specific setting values:

  • 0: Disables the setting.
  • 1: All queries are analyzed.
  • -1: Automatic mode, percentage of queries is inverse to the value of the Max connections setting and depends on the selected host class.

  By default, -1.

• Pg qualstats track constants Management console API CLI

  Enables tracking of already encountered predicates in further queries when statistics are collected by the pg_qualstats module. Only applies when Pg qualstats enabled is enabled.

  This setting is enabled by default.

• Plan cache mode Management console API Terraform

  Determines the type of query plan (generic or custom) to be used to execute prepared statements. The possible values include:

  • auto (PLAN_CACHE_MODE_AUTO for Terraform and API): Automatic selection.
  • force_custom_plan (PLAN_CACHE_MODE_FORCE_CUSTOM_PLAN for Terraform and API): Force custom plans.
  • force_generic_plan (PLAN_CACHE_MODE_FORCE_GENERIC_PLAN for Terraform and API): Force generic plans.

  The default value is auto.

  For more information, see the PostgreSQL documentation.

• Plantuner fix empty table Management console API

  Allows the plantuner module to hide certain indexes from the planner to prevent them from being used in query plans.

  This setting is disabled by default.

• Quote all identifiers All interfaces

  Forces quoting of all identifiers when generating SQL queries from a database, for example, when running the EXPLAIN operation.

  This setting is disabled by default.

  For more information, see the PostgreSQL documentation.

• Random page cost All interfaces

  Sets the planner's estimate of the cost of reading an arbitrary disk page. If the setting value is less than Seq page cost, the planner will prefer index scans.

  The minimum value is 0. The default value is 1.

  For more information, see the PostgreSQL documentation.

• Row security All interfaces

  Controls processing of queries that apply at least one row security policy. If you disable the setting, such queries will return an error.

  This setting is enabled by default.

  For more information, see the PostgreSQL documentation.

• Search path All interfaces

  A comma-separated list of DB schemas. When accessing objects in these schemas, the schema name can be omitted.

  The default value is $user, public (the current user schema and public schema).

  For more information, see the PostgreSQL documentation.

• Seq page cost All interfaces

  Sets the planner's estimate of the cost of a disk page read when doing a series of sequential reads.

  The minimum value is 0. The default value is 1.

  For more information, see the PostgreSQL documentation.

• Session duration timeout Management console API CLI

  The maximum TTL of the longest active session or transaction (in milliseconds). It applies only to sessions with the active and idle in transaction status.

  To make sure the setting does not impact the cluster performance, the longest transaction/session is checked on a regular basis. The checking interval is selected randomly and ranges from 5 to 10 minutes. For example, if you set the setting to 1000, a session will terminate within 1 second + 5 to 10 minutes.

  If the value you set is larger than the default one, this may increase the DB size and slow down the OS.

  The minimum value is 0 (the active session/transaction TTL is unlimited). The maximum value is 2147483647. The default value is 43200000 (12 hours). The minimum granularity for changing the setting value is 1000.

  For more information about possible session statuses, see the PostgreSQL documentation.

• Shared buffers Management console API CLI Terraform

  The amount of memory (in bytes) that PostgreSQL can use for shared memory buffers.

  The minimum value is 131072 (128 KB). The maximum value depends on the selected host class and is equal to 80% of the total RAM size of the Managed Service for PostgreSQL cluster host. By default, the value is 25% of the total RAM size, with a maximum of 8 GB.

  For more information, see the PostgreSQL documentation.

• Shared preload libraries Management console API Terraform

  A comma-separated list of shared libraries to preload when the PostgreSQL server starts. Libraries are required for using some PostgreSQL extensions.

  For more information, see the PostgreSQL documentation.

• Standard conforming strings Management console API Terraform

  Treating backslashes (\) in regular string constants ('...') literally (as specified in the SQL standard) rather than as a special character.

  This setting is enabled by default.

  For more information, see the PostgreSQL documentation.

• Statement timeout Management console API CLI Terraform

  The maximum statement duration (in milliseconds) after which the command is aborted.

  The minimum value is 0, while the maximum one is 2147483647. The default value is 0.

  For more information, see the PostgreSQL documentation.

• Synchronize seqscans All interfaces

  Allows sequential scans of large tables to synchronize with each other, so that concurrent scans read the same block at about the same time. When disabled, ensures pre-8.3 behavior where a sequential scan always started from the beginning of the table.

  This setting is enabled by default.

  For more information, see the PostgreSQL documentation.

• Synchronous commit All interfaces

  Determines at what stage of WAL data processing the server will commit a transaction.

  Acceptable values include:

  Management console/CLI

  Terraform

  API

  • on: A transaction is committed if the WAL is written to the master disk and quorum replica disk.

  • off: A transaction is committed even if its data is not yet in the WAL. Writes are not synchronous, and the transaction data might be lost as a result of a disk subsystem failure.

  • local: A transaction is committed if the WAL is written to the master disk.

  • remote_write: A transaction is committed if the WAL is written to the master disk, and the quorum replica received the WAL and forwarded it to the OS to write it to the disk. If the master disk system is lost and the OS on the quorum replica fails, transaction data with this level of synchronization may be lost.

  • remote_apply: A transaction is committed if the WAL is written to the master disk, and the quorum replica accepted the WAL and applied the changes from it.

    The default value is on.

  • 1 or "SYNCHRONOUS_COMMIT_ON": A transaction is committed if the WAL is written to the master disk and quorum replica disk.

  • 2 or "SYNCHRONOUS_COMMIT_OFF" : A transaction is committed even if its data is not yet in the WAL. Writes are not synchronous, and the transaction data might be lost as a result of a disk subsystem failure.

  • 3 or "SYNCHRONOUS_COMMIT_LOCAL": A transaction is committed if the WAL is written to the master disk.

  • 4 or "SYNCHRONOUS_COMMIT_REMOTE_WRITE": A transaction is committed if the WAL is written to the master disk, and the quorum replica received the WAL and forwarded it to the OS to write it to the disk. If the master disk system is lost and the OS on the quorum replica fails, transaction data with this level of synchronization may be lost.

  • 5 or "SYNCHRONOUS_COMMIT_REMOTE_APPLY": A transaction is committed if the WAL is written to the master disk, and the quorum replica accepted the WAL and applied the changes from it.

    The default value is "SYNCHRONOUS_COMMIT_ON".

  • SYNCHRONOUS_COMMIT_ON: A transaction is committed if the WAL is written to the master disk and quorum replica disk.

  • SYNCHRONOUS_COMMIT_OFF: A transaction is committed even if its data is not yet in the WAL. Writes are not synchronous, and the transaction data might be lost as a result of a disk subsystem failure.

  • SYNCHRONOUS_COMMIT_LOCAL: A transaction is committed if the WAL is written to the master disk.

  • SYNCHRONOUS_COMMIT_REMOTE_WRITE: A transaction is committed if the WAL is written to the master disk, and the quorum replica received the WAL and forwarded it to the OS to write it to the disk. If the master disk system is lost and the OS on the quorum replica fails, transaction data with this level of synchronization may be lost.

  • SYNCHRONOUS_COMMIT_REMOTE_APPLY: A transaction is committed if the WAL is written to the master disk, and the quorum replica accepted the WAL and applied the changes from it.

    The default value is SYNCHRONOUS_COMMIT_ON.

  For more information, see the PostgreSQL documentation.

  The setting applies at the Managed Service for PostgreSQL cluster level, but it can be overridden at the user level.

• Temp buffers All interfaces

  The maximum amount of memory (in bytes) allocated for temporary buffers in each session.

  The minimum value is 100, while the maximum one is 1073741823 (1 GB). The default value is 8388608 (8 MB).

  For more information, see the PostgreSQL documentation.

• Temp file limit Management console API CLI Terraform

  The maximum storage space size (in kilobytes) that a single process can use to create temporary files. A transaction that tries to exceed this limit will be canceled.

  Large queries are executed in the disk space rather than in RAM. Queries that are too large overload the disk and prevent other queries from being executed. The setting prevents queries that degrade performance by limiting the size of temporary files.

  The minimum value is -1 (no limit), while the maximum one is 2147483647 (2 GB). The default value is -1.

  For more information, see the PostgreSQL documentation.

  The setting applies at the Managed Service for PostgreSQL cluster level, but it can be overridden at the user level.

• Timezone All interfaces

  Time zone for output and input of time values.

  Default value: Europe/Moscow.

  For more information, see the PostgreSQL documentation.

• Track activity query size Management console API Terraform

  The amount of memory (in bytes) reserved to store the text of the currently executing command for each active session.

  The minimum value is 100, while the maximum one is 102400. The default value is 1024.

  For more information, see the PostgreSQL documentation.

• Transform null equals All interfaces

  Enables treating the condition expression = NULL as expression IS NULL. The condition is true if the expression has the value NULL, otherwise it is false. According to the SQL standard, expression = NULL always returns NULL (an unknown value).

  This setting is disabled by default (the SQL standard applies).

  For more information, see the PostgreSQL documentation.

• Vacuum cleanup index scale factor All interfaces

  The fraction of heap tuples counted in the previous statistics collection. When running the VACUUM operation, index statistics are considered to be stale if the ratio of newly inserted tuples to the total number of heap tuples exceeds this fraction. In this case, the index will be re-scanned. This feature is not supported by PostgreSQL starting from version 14.

  The minimum value is 0.0, while the maximum one is 10000000000.0. The default value is 0.1.

  For more information, see the PostgreSQL documentation.

• Vacuum cost delay All interfaces

  The amount of time (in milliseconds) for the VACUUM and ANALYZE operations to sleep when the cost limit has been exceeded (see Vacuum cost limit).

  The minimum value is 0, while the maximum one is 100. The default value is 0.

  For more information, see the PostgreSQL documentation.

• Vacuum cost limit All interfaces

  The accumulated cost that will cause the VACUUM process to sleep.

  The minimum value is 1, while the maximum one is 10000. The default value is 200.

  For more information, see the PostgreSQL documentation.

• Vacuum cost page dirty All interfaces

  The estimated cost that is charged when VACUUM modifies a block that was previously clean.

  The minimum value is 0, while the maximum one is 10000. The default value is 20.

  For more information, see the PostgreSQL documentation.

• Vacuum cost page hit All interfaces

  The estimated cost for vacuuming a buffer found in the shared buffer cache.

  The minimum value is 0, while the maximum one is 10000. The default value is 1.

  For more information, see the PostgreSQL documentation.

• Vacuum cost page miss All interfaces

  The estimated cost for vacuuming a buffer that has to be read from a disk.

  The minimum value is 0, while the maximum one is 10000. The default value is 10.

  For more information, see the PostgreSQL documentation.

• Vacuum failsafe age Management console API CLI

  The maximum age of a frozen (already ended) transaction measured as the number of transactions initiated after it. After this value is reached, the VACUUM process triggers vacuuming to avoid transaction counter overflow. PostgreSQL supports this feature starting from version 14.

  The minimum value is 0, while the maximum one is 2100000000. The default value is 1600000000.

  For more information, see the PostgreSQL documentation.

• Vacuum multixact failsafe age Management console API CLI

  The maximum age of a frozen (already ended) multi-transaction measured as the number of multi-transactions initiated after it. After this value is reached, the VACUUM process triggers vacuuming to avoid multi-transaction counter overflow. PostgreSQL supports this feature starting from version 14.

  The minimum value is 0, while the maximum one is 2100000000. The default value is 1600000000.

  For more information, see the PostgreSQL documentation.

• Wal keep size Management console API Terraform

  The minimum size (in bytes) of past log segments kept in the WAL directory so that replicas could fetch them, if needed.

  The minimum value is 0 (past segments are not saved for replication), while the maximum one is 2251799812636672 (2 TB). The default value is 0.

  For more information, see the PostgreSQL documentation.

• Work mem All interfaces

  The base maximum amount of memory to be used by an internal query operation (such as a sort or hash table) before writing to temporary disk files.

  The minimum value is 64, while the maximum one is 2147483647 (2 GB). The default value is 4194304 (4 MB).

  For more information, see the PostgreSQL documentation.

• Xmlbinary All interfaces

  The method used for encoding binary data in XML. The possible values include:

  • base64 (XML_BINARY_BASE64 for Terraform, API, and CLI): BASE64 encoding.
  • hex (XML_BINARY_HEX for Terraform, API, and CLI): Hexadecimal encoding.

  The default value is base64.

  For more information, see the PostgreSQL documentation.

• Xmloption All interfaces

  The default type of conversion between the XML and character string data. The possible values include:

  • document (XML_OPTION_DOCUMENT for Terraform, API, and CLI): An XML document.
  • content (XML_OPTION_CONTENT for Terraform, API, and CLI): A fragment of an XML document.

  The default value is content.

  For more information, see the PostgreSQL documentation.

User-level settingsUser-level settings

These settings affect the behavior of PostgreSQL when handling user queries:

• Conn limit Management console API CLI

  Maximum allowed number of connections for the user.

  In transaction pooling, this setting limits the number of simultaneous connections per user transaction. When using this type of pooling, the user can open thousands of connections, but only N connections can run concurrently (where N is the setting value).

  In session pooling, the setting limits the number of user connections to each host in a PostgreSQL cluster. When using this type of pooling, make sure the setting value is not less than the sum of all connections that can be opened by the user service backends. Each open server connection slightly slows down the OLTP performance for PostgreSQL.

  The following principles apply to session pooling:

  • When adding a user, Managed Service for PostgreSQL reserves 50 connections per host in a PostgreSQL cluster by default. The minimum number of connections per user is 1.

  • The total number of connections reserved for users must not exceed the value of the Max connections parameter. Managed Service for PostgreSQL reserves 15 service connections per host.

    For example, if the cluster has the "max_connections": 100 setting, you can reserve a maximum of 85 connections per cluster host for users.

  • We recommend distributing services that use PostgreSQL across different users and setting the required value for each user. If issues in one service lead to creating a large number of connections, other services will not be affected and will be able to connect to PostgreSQL.

  The setting depends on the selected host class.

• Default transaction isolation Management console API CLI

  For more information, refer to the Default transaction isolation cluster-level setting.

• Grants Management console API CLI Terraform

  Roles granted to the user.

• Lock timeout Management console API CLI

  For more information, refer to the Lock timeout cluster-level setting.

• Log min duration statement Management console API CLI

  For more information, refer to the Log min duration statement cluster-level setting.

  We recommend you to define the meaning of slow query execution for each service and its user and log only the queries that meet the definition. For example, for a web service, a query is slow if it runs for more than one second, while, for the reporting service, it is a query that runs for more than 10 minutes.

  For more information, see the PostgreSQL documentation.

• Log statement Management console API CLI

  For more information, refer to the Log statement cluster-level setting.

• Login Management console API CLI

  Determines whether the user can connect to a PostgreSQL cluster.

  The default value is true, which means the user can connect to the cluster.

• Pooling mode Management console

  The PgBouncer connection pooler's operating mode.

  The possible values include:

  • session: Server connection is assigned to the client when establishing a connection, and is maintained for it. The connection gets back to the pool once the client disconnects.
  • transaction: Server connection is assigned to the client for the transaction execution time only. The connection gets back to the pool once the transaction is completed.
  • statement: Server connection gets back to the pool once the query has been executed. Multi-statement transactions are not allowed in this mode.

  The default value is session.

  For more information, see the PgBouncer documentation.

• Pg audit log Management console

  Defines which user queries will be written to the audit log.

  The setting is only valid if:

  • pgaudit library is connected to the cluster.
  • pgaudit extension is enabled for the database.

  The possible values include:

  • read: SELECT and COPY queries are logged if the data source is a relation or query.
  • write: INSERT, UPDATE, DELETE, TRUNCATE, and COPY queries are logged if the data target is a relation.
  • function: Function invocations and DO sections are logged.
  • role: Statements related to role and privilege management, such as GRANT, REVOKE, or CREATE/ALTER/DROP ROLE, are logged.
  • ddl: Any DDL statements that do not belong to the ROLE class are logged.
  • misc: Miscellaneous commands, such as DISCARD, FETCH, CHECKPOINT, VACUUM, and SET, are logged.
  • misc_set: Miscellaneous SET commands, e.g., SET ROLE, are logged.

  You can select multiple values. By default, audit logs are disabled for the user.

  For more information about setting up audit logs, see Using pgaudit.

• Prepared statements pooling Management console

  Allows using prepared statements with merged transactions.

• Synchronous commit Management console API CLI

  For more information, refer to the Synchronous commit cluster-level setting.

• Temp file limit Management console API CLI

  For more information, refer to the Temp file limit cluster-level setting.

• Wal sender timeout Management console

  Time, in milliseconds, after which inactive replication connections are terminated. Available for Managed Service for PostgreSQL clusters starting with version 12.