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Performance: only plan the dynamic severity branches when they are used #3081

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Performance: only plan the dynamic severity branches when they are used #3081

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79 changes: 57 additions & 22 deletions src/manage_pg.c
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Original file line number Diff line number Diff line change
Expand Up @@ -1121,10 +1121,14 @@ manage_create_sql_functions ()
"$$ LANGUAGE SQL"
" STABLE;");

/* STABLE indicates that the function cannot modify the database,
* and that within a single table scan it will consistently return the same result for the same argument values,
* but that its result could change across SQL statements.
*/
sql ("CREATE OR REPLACE FUNCTION gvmd_user ()"
" RETURNS integer AS $$"
" SELECT current_setting ('gvmd.user.id')::integer;"
"$$ LANGUAGE SQL;");
"$$ LANGUAGE SQL STABLE;");

sql ("CREATE OR REPLACE FUNCTION common_cve (text, text)"
" RETURNS boolean AS $$"
Expand Down Expand Up @@ -1207,7 +1211,7 @@ manage_create_sql_functions ()
" AND ((owner IS NULL)"
" OR (owner = gvmd_user ()))"
" ORDER BY coalesce (owner, 0) DESC LIMIT 1;"
"$$ LANGUAGE SQL;");
"$$ LANGUAGE SQL STABLE;");

sql ("CREATE OR REPLACE FUNCTION current_severity (real, text)"
" RETURNS double precision AS $$"
Expand All @@ -1223,23 +1227,44 @@ manage_create_sql_functions ()

/* result_nvt column (in OVERRIDES_SQL) was added in version 189 */
if (current_db_version >= 189)
sql ("CREATE OR REPLACE FUNCTION report_severity (report integer,"
" overrides integer,"
" min_qod integer)"
{
/* Severity of a report, split into three functions on purpose.
*
* Almost every call is answered by the cached value in
* report_counts, a single index lookup. The four dynamic branches
* underneath scan the results table, and planning those is what is
* expensive.
*
* A function body is only planned when the function is actually
* invoked. Putting the expensive branches in their own function
* and calling it as the second argument of coalesce means it is
* planned only in the rare case where there is no cached value,
* because coalesce stops at the first non null argument at
* execution time.
*
* report_severity itself is left with a body of two function
* calls, no FROM and no CTE, which makes it inlinable while
* STABLE. */
sql ("CREATE OR REPLACE FUNCTION report_severity_cached"
" (report integer, overrides integer, min_qod integer)"
" RETURNS double precision AS $$"
/* Calculate the severity of a report. */
" WITH max_severity"
" AS (SELECT max(severity) AS max"
" FROM report_counts"
" WHERE report = $1"
" AND \"user\" = gvmd_user ()"
" AND override = $2"
" AND min_qod = $3"
" AND (end_time = 0 or end_time >= m_now ()))"
/* The cached severity of a report, or NULL if there is none. */
" SELECT max(severity)::double precision"
" FROM report_counts"
" WHERE report = $1"
" AND \"user\" = gvmd_user ()"
" AND override = $2"
" AND min_qod = $3"
" AND (end_time = 0 or end_time >= m_now ());"
"$$ LANGUAGE SQL STABLE;");

sql ("CREATE OR REPLACE FUNCTION report_severity_dynamic"
" (report integer, overrides integer, min_qod integer)"
" RETURNS double precision AS $$"
/* Severity computed from the results, for reports without a
* cached count. Only called, and therefore only planned, when
* report_severity_cached came back NULL. */
" SELECT CASE"
" WHEN EXISTS (SELECT max FROM max_severity)"
" AND (SELECT max FROM max_severity) IS NOT NULL"
" THEN (SELECT max::double precision FROM max_severity)"
" WHEN dynamic_severity () AND $2::boolean"
/* Dynamic severity, overrides on. */
" THEN (SELECT max"
Expand Down Expand Up @@ -1276,7 +1301,17 @@ manage_create_sql_functions ()
" WHERE results.report = $1"
" AND results.qod >= $3)"
" END;"
"$$ LANGUAGE SQL;");
"$$ LANGUAGE SQL STABLE;");

sql ("CREATE OR REPLACE FUNCTION report_severity (report integer,"
" overrides integer,"
" min_qod integer)"
" RETURNS double precision AS $$"
/* Calculate the severity of a report. */
" SELECT coalesce (report_severity_cached ($1, $2, $3),"
" report_severity_dynamic ($1, $2, $3));"
"$$ LANGUAGE SQL STABLE;");
}

sql ("CREATE OR REPLACE FUNCTION report_host_count (report integer)"
" RETURNS bigint AS $$"
Expand Down Expand Up @@ -1458,7 +1493,7 @@ manage_create_sql_functions ()
" ORDER BY creation_time DESC"
" LIMIT 1 OFFSET 0), $2, $3))"
" END;"
"$$ LANGUAGE SQL;",
"$$ LANGUAGE SQL STABLE;",
TASK_STATUS_DONE);
}
/* column oci_image_target in table task was added in version 261 */
Expand All @@ -1483,7 +1518,7 @@ manage_create_sql_functions ()
" ORDER BY creation_time DESC"
" LIMIT 1 OFFSET 0), $2, $3))"
" END;"
"$$ LANGUAGE SQL;",
"$$ LANGUAGE SQL STABLE;",
TASK_STATUS_DONE);
}
/* column date in table reports was renamed to creation_time in version 245 */
Expand All @@ -1505,7 +1540,7 @@ manage_create_sql_functions ()
" ORDER BY creation_time DESC"
" LIMIT 1 OFFSET 0), $2, $3))"
" END;"
"$$ LANGUAGE SQL;",
"$$ LANGUAGE SQL STABLE;",
TASK_STATUS_DONE);
}
/* result_nvt column (in OVERRIDES_SQL) was added in version 189. */
Expand All @@ -1527,7 +1562,7 @@ manage_create_sql_functions ()
" ORDER BY date DESC"
" LIMIT 1 OFFSET 0), $2, $3))"
" END;"
"$$ LANGUAGE SQL;",
"$$ LANGUAGE SQL STABLE;",
TASK_STATUS_DONE);
}

Expand Down