SVV_VACUUM_SUMMARY - Amazon Redshift


The SVV_VACUUM_SUMMARY view joins the STL_VACUUM, STL_QUERY, and STV_TBL_PERM tables to summarize information about vacuum operations logged by the system. The view returns one row per table per vacuum transaction. The view records the elapsed time of the operation, the number of sort partitions created, the number of merge increments required, and deltas in row and block counts before and after the operation was performed.

SVV_VACUUM_SUMMARY is visible only to superusers. For more information, see Visibility of data in system tables and views.



Table columns

Column name Data type Description
table_name text Name of the vacuumed table.
xid bigint Transaction ID of the VACUUM operation.
sort_partitions bigint Number of sorted partitions created during the sort phase of the vacuum operation.
merge_increments bigint Number of merge increments required to complete the merge phase of the vacuum operation.
elapsed_time bigint Elapsed runtime of the vacuum operation (in microseconds).
row_delta bigint Difference in the total number of table rows before and after the vacuum.
sortedrow_delta bigint Difference in the number of sorted table rows before and after the vacuum.
block_delta integer Difference in block count for the table before and after the vacuum.
max_merge_partitions integer This column is used for performance analysis and represents the maximum number of partitions that vacuum can process for the table per merge phase iteration. (Vacuum sorts the unsorted region into one or more sorted partitions. Depending on the number of columns in the table and the current Amazon Redshift configuration, the merge phase can process a maximum number of partitions in a single merge iteration. The merge phase will still work if the number of sorted partitions exceeds the maximum number of merge partitions, but more merge iterations will be required.)

Sample query

The following query returns statistics for vacuum operations on three different tables. The SALES table was vacuumed twice.

select table_name, xid, sort_partitions as parts, merge_increments as merges, elapsed_time, row_delta, sortedrow_delta as sorted_delta, block_delta from svv_vacuum_summary order by xid; table_ | xid |parts|merges| elapsed_ | row_ | sorted_ | block_ name | | | | time | delta | delta | delta --------+------+-----+------+----------+---------+---------+-------- users | 2985 | 1 | 1 | 61919653 | 0 | 49990 | 20 category| 3982 | 1 | 1 | 24136484 | 0 | 11 | 0 sales | 3992 | 2 | 1 | 71736163 | 0 | 1207192 | 32 sales | 4000 | 1 | 1 | 15363010 | -851648 | -851648 | -140 (4 rows)