ST_CollectOrderOfReadWrite#

Summary#

ST_CollectOrderOfReadWrite indicates that the order of reads and writes should be also collected. It returns true if the setting is successfully performed and false otherwise.

Signature#

Bool ST_CollectOrderOfReadWrite();

Description#

ST_CollectOrderOfReadWrite indicates that the order of reads and writes should be also collected. It returns true if the setting is successfully performed and false otherwise.

After calling this function, the order of reads and writes stops to be collected after calling FT_StoreStatisticalData.

Note

  • Collecting the order of reads and writes may require extra computation time. Thus, we recommend the use of this function to analyze patterns of access in a storage device.
  • The order of reads and writes is collected in the main memory and is automatically deallocated when the database is disconnected.
  • The order of reads and writes is not collected after calling an atomic operation because an atomic operation includes the execution of FT_StoreStatisticalData.

Examples#

--setting the execution name
SELECT FT_SetExecutionName('an insertion');

--let us store the order of reads and writes of the next atomic operation
SELECT ST_CollectOrderOfReadWrite();

--the order of reads and writes is only collected for this operation 
-- because this operation calls the FT_StoreStatisticalData, which stops the collection of the order of reads and writes
SELECT FT_AInsert('r-tree', '/opt/festival_indices/', 50, 
    ST_GeomFromText('POLYGON((-6349160.26886151 -751965.038197354,-6349160.26886151 -606557.85245731,-6211936.96741955 -606557.85245731,-6211936.96741955 -751965.038197354,-6349160.26886151 -751965.038197354))', 3857)
    );

See Also#