14.5. Non-Durable Settings

14.5. Non-Durable Settings
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+ Durability is a database feature that guarantees the recording of + committed transactions even if the server crashes or loses + power. However, durability adds significant database overhead, + so if your site does not require such a guarantee, + PostgreSQL can be configured to run + much faster. The following are configuration changes you can make + to improve performance in such cases. Except as noted below, durability + is still guaranteed in case of a crash of the database software; + only abrupt operating system stoppage creates a risk of data loss + or corruption when these settings are used. + +

+ Place the database cluster's data directory in a memory-backed + file system (i.e., RAM disk). This eliminates all + database disk I/O, but limits data storage to the amount of + available memory (and perhaps swap). +
+ Turn off fsync; there is no need to flush + data to disk. +
+ Turn off synchronous_commit; there might be no + need to force WAL writes to disk on every + commit. This setting does risk transaction loss (though not data + corruption) in case of a crash of the database. +
+ Turn off full_page_writes; there is no need + to guard against partial page writes. +
+ Increase max_wal_size and checkpoint_timeout; this reduces the frequency + of checkpoints, but increases the storage requirements of + /pg_wal. +
+ Create unlogged + tables to avoid WAL writes, though it + makes the tables non-crash-safe. +

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