The only one configurable option is`ptrack.map_size` (in MB). Default is`-1`, which means`ptrack` is turned off.To completely avoidfalse positives it is recommended to set`ptrack.map_size` to`1 / 1000` of expected`PGDATA` size (i.e.`1000` for a 1 TB database), since a single 8 byte`ptrack` map record tracks changes in a standard 8 KB PostgreSQL page.

The only one configurable option is`ptrack.map_size` (in MB). Default is`-1`, which means`ptrack` is turned off.In order to reduce number offalse positives it is recommended to set`ptrack.map_size` to`1 / 1000` of expected`PGDATA` size (i.e.`1000` for a 1 TB database).

To disable`ptrack` and clean up all remaining service files set`ptrack.map_size` to`0`.

* ptrack_version() — returns ptrack version string.

* ptrack_init_lsn() — returns LSN of the last ptrack map initialization.

* ptrack_get_pagemapset(start_lsn pg_lsn) — returns a set of changed data files withbitmapsof changed blocks since specified`start_lsn`.

* ptrack_get_pagemapset(start_lsn pg_lsn) — returns a set of changed data files witha numberof changed blocks and their bitmaps since specified`start_lsn`.

* ptrack_get_change_stat(start_lsn pg_lsn) — returns statistic of changes (number of files, pages and size in MB) since specified`start_lsn`.

Usage example:

postgres=# SELECT ptrack_version();

ptrack_version

2.1

2.2

(1 row)

postgres=# SELECT ptrack_init_lsn();

(1 row)

postgres=# SELECT ptrack_get_pagemapset('0/186F4C8');

ptrack_get_pagemapset

(global/1262,"\\x0100000000000000000000")

(global/2672,"\\x0200000000000000000000")

(global/2671,"\\x0200000000000000000000")

(3 rows)

postgres=# SELECT * FROM ptrack_get_pagemapset('0/185C8C0');

path | pagecount | pagemap

base/16384/1255 |3 | \x001000000005000000000000

base/16384/2674 |3 | \x0000000900010000000000000000

base/16384/2691 |1 | \x00004000000000000000000000

base/16384/2608 |1 | \x000000000000000400000000000000000000

base/16384/2690 |1 | \x000400000000000000000000

(5 rows)

postgres=# SELECT * FROM ptrack_get_change_stat('0/285C8C8');

files | pages | size, MB

20 |25 |0.19531250000000000000

(1 row)