DataFileRead
Short Description
Waiting for a read from a relation data file.
Additional Information​
DataFileRead is an IO wait event and indicates that a process is currently waiting for data to be read from disk or the page cache.
How to reduce this wait​
If you frequently see this wait event then you might want to examine the SQL statements which cause the most I/O and look for optimizations.
- Can you accomplish the same result while examining less data?
- If not, is there an index that might make the processing more efficient?
- Can the SQL be restructured to generate a more optimal plan?
- If no application-level optimisations are possible, then can the I/O subsystem be optimised somehow?
Additional Links​
PostgreSQL documentation - The Statistics Collector
severalnines.com - Tuning Input/Output (I/O) Operations for PostgreSQL
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