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Configuration

Main parameters​

All the GUC parameters require the postmaster restart.

orioledb.main_buffers​

Default64 MB

the size of shared memory, where hot data pages of OrioleDB tables are cached. This parameter is analog of the built-in shared_buffers GUC parameter. A good starting point for this parameter if only OrioleDB tables are used is 1/4 of RAM and setting shared_buffers to default value 128 MB. If OrioleDB and heap tables are used equally, then 1/8 of RAM for this parameter and 1/8 of RAM for shared_buffers.

orioledb.undo_buffers​

Default1 MB

The shared memory ring buffer size for older versions of rows and pages.

Each undo type's circular buffer is at least max_procs * 2 * O_MAX_UNDO_RECORD_SIZE bytes, so the actual buffer at startup may be larger than what this GUC requested when max_procs is high.

orioledb.recovery_pool_size​

Default3

The number of recovery workers for row-level WAL based recovery.

Increasing the sum value of orioledb.recovery_pool_size and orioledb.recovery_idx_pool_size to 50-100% of number of available CPU cores speeds up recovery process for the cluster. You need to set max_worker_processes to more that this sum amount, otherwise OrioleDB will fallback to single-process index build in recovery or to single-process recovery.

orioledb.recovery_idx_pool_size​

Default3

The number of recovery parallel index build workers.

Increasing the sum value of orioledb.recovery_pool_size and orioledb.recovery_idx_pool_size to 50-100% of number of available CPU cores speeds up recovery process for the cluster. You need to set max_worker_processes to more that this sum amount, otherwise OrioleDB will fallback to single-process index build in recovery or to single-process recovery.

orioledb.recovery_queue_size​

Default8 MB

The size of shared memory for message queues related to recovery workers.

orioledb.checkpoint_completion_ratio​

Default0.5

The fraction of OrioleDB tables checkpoint time within the whole checkpoint time. We recommend setting this value to 1.0 if only OrioleDB tables are used.

orioledb.serializable​

Defaulttable_lock

How OrioleDB handles a client request for SERIALIZABLE isolation. OrioleDB does not implement true SSI predicate locking; this enum selects one of three approximations:

  • table_lock (default): take a heavyweight ExclusiveLock on every relation a SERIALIZABLE transaction touches. Two SERIALIZABLE transactions on the same table serialize via the lock manager, and SERIALIZABLE writers block concurrent non-SERIALIZABLE writers (RowExclusiveLock) on that table; non-SERIALIZABLE readers (AccessShareLock) are unaffected. Correct, but coarse — concurrent non-conflicting workloads degrade to serial execution.
  • error: reject SERIALIZABLE transactions with ERRCODE_FEATURE_NOT_SUPPORTED (the legacy behavior).
  • repeatable_read: treat SERIALIZABLE as REPEATABLE READ for OrioleDB tables only — no extra locks are taken, since OrioleDB's CSN-based snapshot already provides per-transaction stable reads. Heap tables in the same transaction continue to use PG's SSI as usual.

Advanced config options​

orioledb.free_tree_buffers​

Default8 MB

Shared memory size for metadata of block allocators for compressed tables. We recommend increasing the value of this parameter to work with large compressed tables.

orioledb.catalog_buffers​

Default8 MB

Shared memory size of table metadata. We recommend increasing the value of this parameter to work with a large number of tables.

orioledb.temp_buffers​

Default64 MB

Size of the per-backend local page pool used for OrioleDB temporary tables. Increase it to improve performance with large temporary tables. This memory is allocated in each backend's private memory, not in shared memory, so memory consumption will scale with the number of backends that touch OrioleDB temporary tables.

orioledb.system_undo_circular_buffer_fraction​

Default0.1

Fraction of orioledb.undo_buffers for older versions of rows and pages in system tables. We recommend increasing the value of this parameter for DDL-intensive workloads. This replaces deprecated parameter orioledb.undo_system_buffers which did the same in absolute memory size.

The remaining orioledb.undo_buffers (except the fraction specified by sum of orioledb.system_undo_circular_buffer_fraction and orioledb.regular_block_undo_circular_buffer_fraction) are reserved for row-level undo logs for regular tables.

orioledb.regular_block_undo_circular_buffer_fraction​

Default0.45

Fraction of orioledb.undo_buffers for block-level undo logs for regular tables.

The remaining orioledb.undo_buffers (except the fraction specified by sum of orioledb.system_undo_circular_buffer_fraction and orioledb.regular_block_undo_circular_buffer_fraction) are reserved for row-level undo logs for regular tables.

orioledb.xid_buffers​

Default1MB

Size of OrioleDB in-memory xid buffers. Each MB can acommodate 65 thousands of xid items corresponding to open transactions. Consider increasing this parameter if you have very big transactions rate.

orioledb.bgwriter_num_workers​

Default1

The number of background writer processes, which flushes dirty pages of OrioleDB tables in the background. We recommend setting values greater than 1 for systems with a large number of CPU cores.

orioledb.max_io_concurrency​

Default0 (off)

Maximum number of concurrent IO operations issued by OrioleDB in parallel. We recommend setting this parameter when the OS kernel becomes a bottleneck for high concurrent IO.

orioledb.device_filename​

DefaultNot set

Path to the block device for block device mode.

orioledb.device_length​

Default1 GB

The length of the block device.

orioledb.use_mmap​

Defaultoff

Specify whether to use mmap to work with the block device. We recommend setting on value for NVRAM.

orioledb.default_compress​

Default-1 (no compression)

Default block-level compression level for tables' data structures.

orioledb.default_primary_compress​

Default-1 (no compression)

Default block-level compression level for tables' primary keys.

orioledb.default_toast_compress​

Default-1 (no compression)

Default block-level compression level for tables' TOASTed values.

orioledb.table_description_compress​

Defaultoff

Display compression column in orioledb_table_description.

orioledb.use_sparse_files​

Defaultoff

Try to allocate files as sparse at filesystem level. Saves occupied space on disk by excluding non-allocated regions in file from occupying disk space. It's an experimental option.

orioledb.strict_mode​

Defaultoff

Controls how OrioleDB reacts when a session requests a feature it does not yet support on an OrioleDB table. When off, OrioleDB emits a WARNING and silently falls back to the non-concurrent or plain variant. When on, OrioleDB raises an ERROR instead, which is useful to catch unintended fallback in tests and CI.

Options for undo-based rewind (experimental)​

orioledb.enable_rewind​

Defaultoff

Enable undo-based rewind.

orioledb.rewind_max_time​

Default500

Maximum age in seconds from now of transaction after which it is completed and removed from buffer. It's a time limit for a rewind.

orioledb.rewind_max_transactions​

Default86400

Maximum number of rewind transaction items that are stored for a rewind. Older rewind transaction items are completed and removed from the buffer so this specifies maximum rewind age. If there are subtransactions they also occupy rewind items in a rewind buffer.

orioledb.rewind_max_transactions and orioledb.rewind_max_time work together so if a transaction is older than any one of these thresholds it is past the rewind capability and could not be rewound to.

orioledb.rewind_buffers​

Default1MB

Size of OrioleDB in-memory rewind buffers. Each MB can acommodate around 8000 rewind transaction items. If you have enough memory set it near a value (orioledb.rewind_max_transactions / 8000) MB to avoid writing rewind info to disk.

orioledb.logical_xid_buffers​

Default512KB

Size of OrioleDB in-memory buffers for logical transaction IDs to be assigned to running subtransactions. Each MB can accommodate 8 million of running subtransactions. So default value corresponds to 4 million subtransactions.

Debugging options​

orioledb.debug_disable_pools_limit​

Defaultoff

Disable minimal limit for orioledb.main_buffers, orioledb.free_tree_buffers, orioledb.catalog_buffers for debug.

orioledb.enable_stopevents​

Defaultoff

Enable stop events.

orioledb.trace_stopevents​

Defaultoff

Trace all the stop events to the system log.

orioledb.debug_disable_bgwriter​

Defaultoff

Disable bgwriter for debug.

orioledb.debug_checkpoint_timeout​

Defaultcheckpoint_timeout

Sets the maximum time between automatic WAL checkpoints. Setting this value to a lower value than checkpoint_timeout can make OrioleDB checkpoints more often for testing.

orioledb.remove_old_checkpoint_files​

Defaulton

Remove temporary *.tmp and *.map files after checkpoint.

orioledb.skip_unmodified_trees​

Defaulton

Skip reading of unmodified trees during checkpointing.

orioledb.debug_max_bridge_ctid_blkno​

DefaultNA

Sets maximum value for bridge ctid for its overflow testing.

orioledb.replay_until_lsn​

DefaultNA

Specifies the cutoff LSN at or after which OrioleDB will permanently stop applying its WAL records during recovery. Replay stops when the WAL read position reaches this LSN. replay_until_lsn must not be earlier than the LSN of the latest completed OrioleDB checkpoint. Specifying replay_until_lsn earlier than the LSN of the latest completed OrioleDB checkpoint will have no effect (a warning will be logged at next startup).

Data consistency

This is a last-resort disaster recovery mechanism strictly comparable to pg_resetwal. It intentionally induces a split-brain state: PostgreSQL core catalogs and standard heap tables will continue replaying WAL, while OrioleDB tables remain at the specified LSN.

Additional GUC's for experimental s3 mode