SingleStore DB

information_schema.LMV_JOIN_OPTIMIZATION_RESULTS

This table contains information about the results of join optimization operations. This table displays rows for each query plan and each table joined in the query plan.

Column Name

Description

ACTIVITY_NAME

The activity name of the query plan. This corresponds to ACTIVITY_NAME in mv_activities.

QUERY_TEXT

The text of the query.

DATABASE_NAME

The name of the related database.

TABLE_NAME

The name of a table within a given join.

IS_LOCAL

Whether or not a given join is local.

SEQ_NUMBER

The sequence number of this row among the rows for this query plan.

TABLE_COUNT

The number of tables included in a given join.

TABLE_INDEX

The position of the table in its join.

FILTER_SELECTIVITY

The estimated fraction of rows that satisfy the filter conditions on a given table (not including conditions involving multiple tables, i.e. join conditions)

JOIN_SELECTIVITY

The estimated fraction of rows that satisfy the join conditions.

TABLE_CARD

The estimated rowcount of the table.

CARD_POST_FILTER

The estimated rowcount of the table after filter conditions on this table only.

CARD_POST_JOIN

The estimated rowcount of the join so far after joining this table.

COST_SO_FAR

The estimated cost of executing a given join so far, according to the optimizer’s cost model.