NEWS

Release 1.8.0
=============

This release fixes a bug in the squeeze.squeeze_table() function, which can
cause data corruption. The problem can occur if other clients run DDL
statements or squeeze other tables around the time the function starts its
execution.

Automatic launching by the scheduler worker (as described in the "Register
table for regular processing" section of README) is not affected.


Release 1.7.0
=============

New features
------------

1. Make the code compatible with PostgreSQL server version 17.

2. Do not copy the values of dropped columns into the new table storage
   (file).

   So far, only the whole rows (the deleted ones) were considered to
   contribute to the table bloat. Now we also reclaim the space occupied by
   dropped columns.

3. Let the squeeze.squeeze_table function raise ERROR.

   So far, the function only inserted record into the squeeze.log table if the
   processing was successful, and into squeeze.errors if it failed. Now, in
   the case of failure, the function also prints out the error message into
   the console.

4. Do not let the squeeze workers run if there is currently no work for them.

   For automatic processing, one scheduler worker per database needs to run,
   but the actual squeeze worker is only started if particular table appears
   to be bloated. Once done with the processing, the squeeze worker exits
   instead of waiting for another task.

5. Improved parallelism of the squeeze workers.

   Multiple worker processes (one per table) can be used since the release
   1.6, but so far it was still possible that the work gets serialized due to
   the logical decoding setup. Those limitations have been relaxed in 1.7.

Bug fixes
---------

1. Fixed broken setup of "shared memory hooks".

   This could cause server crash if other extensions installed their hooks as
   well. (https://github.com/cybertec-postgresql/pg_squeeze/issues/68)

2. Fixed evaluation of the squeeze.max_xlock_time configuration variable.

   Due to this bug, pg_squeeze behaved as if the timeout was set to much lower
   value. (The bug had no effect if the variable was set to 0, which is the
   default.)

3. Fixed permissions checks for the squeeze.pgstattuple_approx() function.

   Like with other functions of this extension, the SUPERUSER role attribute
   is not needed for execution. The REPLICATION attribute is sufficient.

4. Update BRIN indexes when appropriate.

   If a row was updated during the table processing and only the attributes of
   "summarizing" (BRIN) indexes changed, pg_squeeze could fail to update those
   indexes.

   This bug only affects pg_squeeze on PostgreSQL 16.


Release 1.6.1
=============

Bug fixes
---------

1. Pass function argument as Datum rather than the "raw" timestamp.

The bug can cause crash on platforms where timestamp is passed by reference
(which usually means the 32-bit systems).


Release 1.6.0
=============

New features
------------

1. Make the code compatible with PostgreSQL server version 16.

2. Allow processing of multiple tables at a time, even if the are in the same
   database.

3. Enhanced monitoring - see the squeeze.get_active_workers() function as well
   as the new columns of the squeeze.log table.

Bug fixes
---------

1. Fixed the mechanism that checks the number of workers per database. This
   also fixes the stop_worker() function so that it does not miss workers
   anymore.

Note
----

The behavior of the squeeze_table() function changes in this version, see
README for more information.


Release 1.5.0
=============

This release only updates the code so that it is compatible with PostgreSQL
server version 15.


Release 1.4.1
=============

Bug fixes
---------

1. Adapted the code to changed API of PostgreSQL core code.

   Signature of NewHeapCreateToastTable() changed between PG 14beta3 and
   14rc1.


Release 1.4.0
=============

Bug fixes
---------

1. Fixed determination of WAL insert position before processing the concurrent
   changes.

   Without this fix, some data changes performed during the initial load by
   sessions which have synchronous_commit=off can be lost.

New features
------------

1. Decode WAL even during the initial load, although the changes decoded
   cannot be applied during the load. This allows WAL segments to be recycled
   during the load. Note that a huge amount of logical changes can be
   generated by the initial load itself, but these do not have to be
   decoded. Thus only changes done by other transactions need to be stored,
   and applied as soon as the initial load has completed.

2. Process even tables with FULL replica identity, as long as they do have a
   primary key.


Release 1.3.1
=============

Bug fixes
---------

1. Fixed failure to run the CREATE EXTENSION command on PostgreSQL server v10.

   The problem is that PG10 does not support arrays of domain type.


Release 1.3.0
=============

New features
------------

1. Support for PostgreSQL 13.

2. Enhanced scheduling.

   Instead of passing an array of timetz values, the DBA can now specify the
   schedule in a way similar to crontab, i.e. days can be specified too. Note
   that "ALTER EXTENSION pg_squeeze UPDATE" command does not handle conversion
   of the schedule - instead it deletes the existing contents of the
   "squeeze"."tables" configuration table.

   Another enhancement is that two background workers are now used: one that
   checks the schedule and another one that checks the amount of bloat and
   possibly squeezes the tables. This makes the scheduling more accurate.


Bug fixes
---------

1. Release the replication slot if ERROR is encountered by the background
   worker during the call of the squeeze_table() function. For interactive
   calls, pg_squeeze does not have to care because PG core does.

2. Release lock on the pg_squeeze extension (which ensures that no more than
   one instance of each background worker can be launched) when exiting due to
   pg_cancel_backend().


Release 1.2.0
=============

New features
------------

1. Support for PostgreSQL 12.

2. Do not hide old row versions from VACUUM for longer than necessary.

   The "initial load" phase of the squeeze process uses a "historic snapshot"
   to retrieve the table data as it was when the squeeze_table() function
   started. This data must be protected from VACUUM.

   pg_squeeze uses replication slot for this purpose, so it's not possible to
   protect only one particular table from VACUUM. Since this approach affects
   the whole cluster, the protection needs to be released as soon as the
   initial load has completed.

3. Try harder to make WAL segments available for archiving.

   Data changes performed during the squeeze process are retrieved from
   WAL. Now we check more often if particular WAL segment is still needed by
   pg_squeeze.


Release 1.1.1
=============

Bug fixes
---------

1. Fixed failure to find equality operator for index scan. The failure was
   observed when the column type (e.g. varchar) differed from the operator
   class input type (e.g. text).

2. Use index reloptions in the correct format when creating indexes on the new
   table. The bug could cause crash, however it should not lead to corruption
   of the original reloptions since the new catalog entries are eventually
   dropped (only storage of the new index is used).


Release 1.1.0
=============

New features
------------

1. Instead of configuring "first_check" and "task_interval", administrator now
   passes a "schedule" array of timestamps at which table should be squeezed.

2. Table no longer needs to have the user_catalog_table storage option set
   before it can be passed to squeeze_table() function.

   Now INSERT ... ON CONFLICT ... command no longer raises ERROR if trying to
   access table that is just being squeezed. Another advantage is this change
   is that calls of the squeeze_table() function are now easier.

3. No longer disable autovacuum for the table being squeezed.

   The additional code complexity is probably not worth and it does not stop
   already running VACUUM. It's responsibility of the DBA not to allow VACUUM
   to waste resources on a table which should be treated by pg_squeeze.


Bug fixes
---------

1. Close pg_class relation and its scan if exiting early (i.e. catalog change
   was detected).

2. Defend against race conditions that allow for applying of the concurrent
   changes which have already been captured by the initial load. In such a
   case the squeeze_table() function can raise ERROR due to attempt to insert
   duplicate value of identity key, or due to failure to update or delete row
   that no longer exists.

3. Use the correct snapshot for the initial load.

   So far the squeeze_table() function could have used an obsolete snapshot if
   some transaction(s) started after the snapshot builder reached
   SNAPBUILD_FULL_SNAPSHOT state and committed before
   SNAPBUILD_CONSISTENT. Both the initial load and the logical decoding used
   to miss such transactions.

   This problem could only happen after the bug fix #2 had been
   implemented. Before that at least the logical decoding captured the
   problematic transactions because it (the decoding) started earlier than
   necessary.

   No data loss was reported so far, but we still recommend you to upgrade
   pg_squeeze to the version that includes this fix.

4. Do not use "initial load memory context" to fetch tuples from table or
   index.

   If the load takes place in multiple "batches" (i.e. tuplesort is not used),
   that memory context gets freed before the next batch starts and the call fo
   squeeze_table() function results in SEGFAULT.

5. Do not close relation cache entry for index if some field is yet to be
   accessed.

6. Include composite types in the checks of concurrent catalog changes. If
   table has a column of a composite data type and the type is altered during
   the squeeze, the squeeze_table() function raises ERROR.


Release 1.0.1
=============

Bug fixes
---------

1. Try harder to avoid out-of-memory conditions during the initial table load.