\echo Use "ALTER EXTENSION pg_sift UPDATE TO '4.2.1'" to load this file. \quit

-- The two triggers of an index with track_changes were its dependents, and DROP INDEX CONCURRENTLY refused such an index (it deletes what depends on the index first, which assigns
-- the transaction an xid that the command does not allow). The index now depends on its triggers and the transaction that deletes it removes them. This function makes the
-- existing indexes so (a second run finds nothing to convert). The library finds the triggers in both forms, so the indexes of an earlier release work meanwhile; only their DROP INDEX
-- CONCURRENTLY waits for the conversion.
-- The script of the next minor from 4.2 must create it as well (CREATE OR REPLACE: a patch release moves the extension version back to 4.2 and forward again).
CREATE OR REPLACE FUNCTION sift.col_track_convert() RETURNS integer
	AS 'MODULE_PATHNAME', 'sift_col_track_convert' LANGUAGE C STRICT;

COMMENT ON FUNCTION sift.col_track_convert() IS 'Makes each sift_col index the dependent of its two track_changes triggers (what 4.2.1 does for the indexes of an older release), so that DROP INDEX CONCURRENTLY can drop it; returns the number of triggers converted';

SELECT sift.col_track_convert();

-- sift.workers and sift.col_index_status read the metapage of every sift index of the database, and an index that CREATE INDEX CONCURRENTLY or REINDEX CONCURRENTLY is still building (or a failed one left) has none:
-- one such index made both views fail for the whole database, on the primary and, replaying the build, on a standby ("could not read blocks", "invalid page layout"). They list the indexes that are ready.
CREATE OR REPLACE VIEW sift.workers AS
	SELECT c.oid::regclass AS index, a.amname::text AS kind, w.segments, w.sealed, w.running, w.failures, w.failed_at, w.next_retry,
		   w.error_code, w.last_error,
		   CASE WHEN a.amname = 'sift_col' THEN sift.col_maintenance_due(c.oid) END AS due
	FROM pg_class c
	JOIN pg_am a ON a.oid = c.relam AND a.amname IN ('sift', 'sift_col')
	JOIN pg_index i ON i.indexrelid = c.oid AND i.indisready
	CROSS JOIN LATERAL sift.worker_state(c.oid) w
	WHERE c.relkind = 'i' AND has_table_privilege(i.indrelid, 'SELECT') AND w.segments IS NOT NULL
	UNION ALL
	SELECT c.oid::regclass, a.amname::text, w.segments, w.sealed, w.running, w.failures, w.failed_at, w.next_retry,
		   w.error_code, w.last_error, NULL::text
	FROM pg_class c
	JOIN pg_am a ON a.oid = c.relam AND a.amname = 'sift_table'
	CROSS JOIN LATERAL sift.worker_state(c.oid) w
	WHERE c.relkind IN ('r', 'm') AND has_table_privilege(c.oid, 'SELECT') AND w.segments IS NOT NULL;

CREATE OR REPLACE VIEW sift.col_index_status AS
	SELECT c.oid::regclass AS index, m.heap AS "table",
		   pg_relation_size(c.oid) AS index_bytes, x.bytes AS segment_bytes,
		   x.free_blocks * bs.n AS free_bytes, x.reusable_blocks * bs.n AS reusable_bytes,
		   x.rows AS segment_rows, x.segments, x.max_segments, s.largest_segment_bytes, x.units, s.listed_units,
		   s.dirty_segments, s.dead_rows, round(100.0 * s.dead_rows / NULLIF(x.rows, 0), 2) AS dead_pct,
		   s.buffer_rows, w.sealed AS sealed_buffers, w.running, w.failures, w.next_retry,
		   m.last_vacuum, m.changed_rows, m.vacuum_at, m.rewrite_due AS due, m.last_request, m.blocked_by
	FROM pg_class c
	JOIN pg_am a ON a.oid = c.relam AND a.amname = 'sift_col'
	JOIN pg_index i ON i.indexrelid = c.oid AND i.indisready
	CROSS JOIN (SELECT current_setting('block_size')::int8 AS n) bs
	CROSS JOIN LATERAL sift.col_index_info(c.oid) x
	CROSS JOIN LATERAL sift.worker_state(c.oid) w
	CROSS JOIN LATERAL sift.col_maintenance_status(c.oid) m
	CROSS JOIN LATERAL (SELECT max(bytes) FILTER (WHERE kind = 'immutable') AS largest_segment_bytes,
							   sum(units) AS listed_units, count(*) FILTER (WHERE dirty) AS dirty_segments,
							   coalesce(sum(dead_rows), 0) AS dead_rows,
							   coalesce(sum(rows) FILTER (WHERE kind <> 'immutable'), 0) AS buffer_rows
						FROM sift.col_segments(c.oid)) s
	WHERE has_table_privilege(i.indrelid, 'SELECT') AND w.segments IS NOT NULL;