SVV_TABLE_INFO - Amazon Redshift
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Shows summary information for tables in the database. The view filters system tables and shows only user-defined tables.

You can use the SVV_TABLE_INFO view to diagnose and address table design issues that can influence query performance. This includes issues with compression encoding, distribution keys, sort style, data distribution skew, table size, and statistics. The SVV_TABLE_INFO view doesn't return any information for empty tables.

The SVV_TABLE_INFO view summarizes information from the STV_BLOCKLIST, STV_NODE_STORAGE_CAPACITY, STV_TBL_PERM, and STV_SLICES system tables and from the PG_DATABASE, PG_ATTRIBUTE, PG_CLASS, PG_NAMESPACE, and PG_TYPE catalog tables.

SVV_TABLE_INFO is visible only to superusers. For more information, see Visibility of data in system tables and views. To permit a user to query the view, grant SELECT permission on SVV_TABLE_INFO to the user.

Table columns

Column name Data type Description
database text Database name.
schema text Schema name.
table_id oid Table ID.
table text Table name.
encoded text Value that indicates whether any column has compression encoding defined.
diststyle text Distribution style or distribution key column, if key distribution is defined. Possible values include EVEN, KEY(column), ALL, AUTO(ALL), AUTO(EVEN), and AUTO(KEY(column)).
sortkey1 text First column in the sort key, if a sort key is defined. Possible values include column, AUTO(SORTKEY), and AUTO(SORTKEY(column)).
max_varchar integer Size of the largest column that uses a VARCHAR data type.
sortkey1_enc character(32) Compression encoding of the first column in the sort key, if a sort key is defined.
sortkey_num integer Number of columns defined as sort keys.
size bigint Size of the table, in 1-MB data blocks.
pct_used numeric(10,4) Percent of available space that is used by the table.
empty bigint For internal use. This column is no longer used and will be removed in a future release.
unsorted numeric(5,2) Percent of unsorted rows in the table.
stats_off numeric(5,2) Number that indicates how stale the table's statistics are; 0 is current, 100 is out of date.
tbl_rows numeric(38,0) Total number of rows in the table. This value includes rows marked for deletion, but not yet vacuumed.
skew_sortkey1 numeric(19,2) Ratio of the size of the largest non-sort key column to the size of the first column of the sort key, if a sort key is defined. Use this value to evaluate the effectiveness of the sort key.
skew_rows numeric(19,2) Ratio of the number of rows in the slice with the most rows to the number of rows in the slice with the fewest rows.
estimated_visible_rows numeric(38,0) The estimated rows in the table. This value does not include rows marked for deletion.
risk_event text Risk information about a table. The field is separated into parts:
  • The risk_type, where 1 indicates that a COPY command with the EXPLICIT_IDS option ran. Amazon Redshift no longer checks the uniqueness of IDENTITY columns in the table. For more information, see EXPLICIT_IDS.

  • The transaction ID, xid, that introduced the risk.

  • The timestamp when the COPY command ran.

The following example shows the values in the field.

1|1107|2019-06-22 07:16:11.292952
vacuum_sort_benefit numeric(12,2) The estimated maximum percentage improvement of scan query performance when you run vacuum sort.
create_time timestamp without time zone The timestamp for when the table was created.

Sample queries

The following example shows encoding, distribution style, sorting, and data skew for all user-defined tables in the database. Here, "table" must be enclosed in double quotation marks because it is a reserved word.

select "table", encoded, diststyle, sortkey1, skew_sortkey1, skew_rows from svv_table_info order by 1; table | encoded | diststyle | sortkey1 | skew_sortkey1 | skew_rows ---------------+---------+-----------------+--------------+---------------+---------- category | N | EVEN | | | date | N | ALL | dateid | 1.00 | event | Y | KEY(eventid) | dateid | 1.00 | 1.02 listing | Y | KEY(listid) | dateid | 1.00 | 1.01 sales | Y | KEY(listid) | dateid | 1.00 | 1.02 users | Y | KEY(userid) | userid | 1.00 | 1.01 venue | N | ALL | venueid | 1.00 | (7 rows)