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Maintenance Working Memory

The default Postgres maintenance_work_mem value of 64MB is quite conservative and can slow down parallel index builds. We recommend at least 64MB per parallel worker.

postgresql.conf
maintenance_work_mem = 16GB

Each worker is required to have at least 15MB memory. If maintenance_work_mem is set too low, an error will be returned.

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Parallel Indexing Workers

ParadeDB uses Postgres’ max_parallel_maintenance_workers setting to determine the degree of parallelism during CREATE INDEX/REINDEX. Postgres’ default is 2, which may be too low for large tables.

SET max_parallel_maintenance_workers = 8;

In order for max_parallel_maintenance_workers to take effect, it must be less than or equal to both max_parallel_workers and max_worker_processes.

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Target Segment Count

By default, CREATE INDEX/REINDEX will create as many segments as there are CPUs on the host machine. This can be changed with paradedb.target_segment_count.

For optimal performance, the segment count should equal the number of parallel workers that a query can receive, which is controlled by max_parallel_workers_per_gather. If max_parallel_workers_per_gather is greater than the number of CPUs on the host machine, then increasing the target segment count to match max_parallel_workers_per_gather can improve query performance.

SET paradedb.target_segment_count = 32;