PL/pgSQL coverage reporting

This contrib module can be used to get useful statement execution info for your stored PL/pgSQL functions from which you can extract for example statement and branch test coverage.

Installation

Extract the plpgsql_coverage directory to you postgresql sources contrib directory.

Then run make install This will install plugin to your postgres server.

Usage

First you need to load the plugin, to do that execute following statement:

LOAD '$libdir/plugins/plpgsql_coverage';

Then enable the plugin by setting configuring table to which it should store it's data to:

SET plpgsql_coverage.stats_table_name = 'public.coverage';

After this you can execute your PL/pgSQL functions and the execution stats will be stored in the table you specified above. The table structure is following:

CREATE TABLE public.coverage (
    func_oid OID,     -- Oid of the function
    line_number INT,  -- Line number of the statement
    stmt_number INT,  -- "Id" of the statement within the function
    stmt_type TEXT,   -- Human readable statement type
    exec_count INT8,  -- Number of executions of given statement
    stmt_parent INT,  -- Reference to parent statement "id" (to a block, IF, CASE and similar statements...)
    stmt_branch INT   -- In which branch of the parent statement is this one located (when parent is IF or CASE)
);

You can disable the plugin by unsetting the plpgsql_coverage.stats_table_name config variable:

SET plpgsql_coverage.stats_table_name = '';

Examples of useful queries

All of these assume you are using public.coverage as a table name.

Overview of executed source lines:

SELECT
    fnoid,
    ln,
    src,
    stmt_number,
    stmt_type,
    exec_count,
    stmt_parent,
    stmt_branch
FROM (
    SELECT
        regexp_split_to_table(prosrc, $$\n$$) AS src,
        generate_series(1,array_upper(regexp_split_to_array(prosrc, $$\n$$) , 1)) AS ln,
        oid AS fnoid
    FROM
        pg_proc
    WHERE
        oid IN (SELECT DISTINCT func_oid FROM public.coverage)
    ) AS q
LEFT JOIN
    public.coverage ON (func_oid = fnoid AND ln = line_number+1)
ORDER BY
    fnoid, ln;

Statement coverage percentage:

SELECT
    (SELECT proname FROM pg_proc WHERE oid = func_oid) AS function_name,
    count(*) AS statements, sum(least(exec_count, 1)) AS exec_statements,
    to_char(100::numeric*sum(least(exec_count, 1))/greatest(count(*), 1), '990.9%') AS coverage
FROM
    public.coverage
GROUP BY
    func_oid;

Branch coverage percentage:

SELECT
    (SELECT proname FROM pg_proc WHERE oid = a.func_oid) AS function_name,
    sum(a.branches) AS branches, count(b.exec_branches) AS exec_branches,
    to_char(100::numeric*count(b.exec_branches)/greatest(sum(a.branches), 1), '990.9%') AS coverage
FROM (
    SELECT func_oid, stmt_parent, count(*) AS branches
    FROM (
        SELECT func_oid, stmt_parent, stmt_branch
        FROM public.coverage
        GROUP BY func_oid, stmt_parent, stmt_branch
    ) AS q
    GROUP BY func_oid, stmt_parent
) AS a
LEFT JOIN (
    SELECT func_oid, stmt_parent, count(*) AS exec_branches
    FROM (
        SELECT DISTINCT ON (func_oid, stmt_parent, stmt_branch) func_oid, stmt_parent, stmt_branch, exec_count
        FROM public.coverage
        ORDER BY func_oid, stmt_parent, stmt_branch
    ) AS q
    GROUP BY func_oid, stmt_parent
    HAVING sum(exec_count) > 0
) AS b ON (a.func_oid = b.func_oid AND a.stmt_parent = b.stmt_parent)
GROUP BY a.func_oid;