Gather Merge nodes combine the output of child nodes, which are executed by parallel workers.

They consume sorted data, and preserve this sort order.

Gather Merge fields

• Parent Relationship

• Parallel Aware

• Startup Cost

• Total Cost

• Plan Rows

• Plan Width

• Actual Startup Time

• Actual Total Time

• Actual Rows

• Actual Loops

• Output

• Workers Planned

• Workers Launched

• Shared Hit Blocks

• Shared Read Blocks

• Shared Dirtied Blocks

• Shared Written Blocks

• Local Hit Blocks

• Local Read Blocks

• Local Dirtied Blocks

• Local Written Blocks

• Temp Read Blocks

• Temp Written Blocks

• Shared I/O Read Time

• Shared I/O Write Time

• Local I/O Read Time

• Local I/O Write Time

• Temp I/O Read Time

• Temp I/O Write Time

Related operations

• Gather

Related official docs

• How Parallel Query Works

Further reading

• Increasing the max workers per gather – pgMustard