Waiting for PostgreSQL 13 – Add functions gcd() and lcm() for integer and numeric types.

On 25th of January 2020, Dean Rasheed committed patch:

Add functions gcd() and lcm() for integer and numeric types.
 
These compute the greatest common divisor and least common multiple of
a pair of numbers using the Euclidean algorithm.
 
Vik Fearing, reviewed by Fabien Coelho.
 
Discussion: https://postgr.es/m/-e3f1-5bbc-21db-@2ndquadrant.com

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Waiting for PostgreSQL 13 – Allow vacuum command to process indexes in parallel.

On 20th of January 2020, Amit Kapila committed patch:

Allow vacuum command to process indexes in parallel.
 
This feature allows the vacuum to leverage multiple CPUs in order to
process indexes.  This enables us to perform index vacuuming and index
cleanup with background workers.  This adds a PARALLEL option to VACUUM
command where the user can specify the number of workers that can be used
to perform the command which is limited by the number of indexes on a
table.  Specifying zero as a number of workers will disable parallelism.
This option can't be used with the FULL option.
 
Each index is processed by at most one vacuum process.  Therefore parallel
vacuum can be used when the table has at least two indexes.
 
The parallel degree is either specified by the user or determined based on
the number of indexes that the table has, and further limited by
max_parallel_maintenance_workers.  The index can participate in parallel
vacuum iff it's size is greater than min_parallel_index_scan_size.
 
Author: Masahiko Sawada and Amit Kapila
 
Mahendra Singh and Sergei Kornilov
 
Discussion:
https://postgr.es/m/CAD21AoDTPMgzSkV4E3SFo1CH_x50bf5PqZFQf4jmqjk-C03BWg@mail.gmail.com
https://postgr.es/m/CAA4eK1J-VoR9gzS5E75pcD-OH0mEyCdp8RihcwKrcuw7J-Q0+w@mail.gmail.com

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Waiting for PostgreSQL 13 – ALTER TABLE … ALTER COLUMN … DROP EXPRESSION

Title: Waiting for PostgreSQL 13 – ALTER TABLE … ALTER COLUMN … DROP EXPRESSION

On 14th of January 2020, Peter Eisentraut committed patch:

ALTER TABLE ... ALTER COLUMN ... DROP EXPRESSION 
 
Add an ALTER TABLE subcommand for dropping the generated property from
a column, per SQL standard.
 
Discussion: https://www.postgresql.org/message-id/flat/-946e-0453-d841-%402ndquadrant.com

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Waiting for PostgreSQL 13 – Allow invisible PROMPT2 in psql.

On 19th of November 2019, Thomas Munro committed patch:

Allow invisible PROMPT2 in psql. 
 
Keep track of the visible width of PROMPT1, and provide %w as a way
for PROMPT2 to generate the same number of spaces.
 
Author: Thomas Munro, with ideas from others
 
Discussion: https://postgr.es/m/CA%2BhUKG%2BzGd7RigjWbxwhzGW59gUpf76ydQECeGdEdodH6nd__A%40mail.gmail.com

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Waiting for PostgreSQL 13 – Introduce the ‘force’ option for the Drop Database command.

On 13rd of November 2019, Amit Kapila committed patch:

Introduce the 'force' option for the Drop Database command.
 
 
This new option terminates the other sessions connected to the target
database and then drop it.  To terminate other sessions, the current user
must have desired permissions (same as pg_terminate_backend()).  We don't
allow to terminate the sessions if prepared transactions, active logical
replication slots or subscriptions are present in the target database.
 
Author: Pavel Stehule with changes by me
 
Ryan Lambert and Amit Kapila
Discussion: https://postgr.es/m/CAP_rwwmLJJbn70vLOZFpxGw3XD7nLB_7+NKz46H5EOO2k5H7OQ@mail.gmail.com

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Waiting for PostgreSQL 13 – Allow sampling of statements depending on duration

On 6th of November 2019, Tomas Vondra committed patch:

Allow sampling of statements depending on duration
 
This allows logging a sample of statements, without incurring excessive
log traffic (which may impact performance).  This can be useful when
analyzing workloads with lots of short queries.
 
The sampling is configured using two new GUC parameters:
 
 * log_min_duration_sample - minimum required statement duration
 
 * log_statement_sample_rate - sample rate (0.0 - 1.0)
 
Only statements with duration exceeding log_min_duration_sample are
considered for sampling. To enable sampling, both those GUCs have to
be set correctly.
 
The existing log_min_duration_statement GUC has a higher priority, i.e.
statements with duration exceeding log_min_duration_statement will be
always logged, irrespectedly of how the sampling is configured. This
means only configurations
 
  log_min_duration_sample < log_min_duration_statement
 
do actually sample the statements, instead of logging everything.
 
Author: Adrien Nayrat
 
Discussion: https://postgr.es/m/-a8f7-3be2-155a-@anayrat.info

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Waiting for PostgreSQL 13 – pgbench: add –partitions and –partition-method options.

On 3rd of October 2019, Amit Kapila committed patch:

pgbench: add --partitions and --partition-method options.
 
These new options allow users to partition the pgbench_accounts table by
specifying the number of partitions and partitioning method.  The values
allowed for partitioning method are range and hash.
 
This feature allows users to measure the overhead of partitioning if any.
 
Author: Fabien COELHO
 
Alvaro Herrera
Discussion: https://postgr.es/m/alpine.DEB.2.21..7008@lancre

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Waiting for PostgreSQL 13 – Support for FF1-FF6 and SSSS datetime format patterns

On 16th of September 2019, Alexander Korotkov committed two patches:

First patch:

Support for SSSSS datetime format pattern
 
SQL Standard 2016 defines SSSSS format pattern for seconds past midnight in
jsonpath .datetime() method and CAST (... FORMAT ...) SQL clause.  In our
datetime parsing engine we currently support it with SSSS name.
 
This commit adds SSSSS as an alias for SSSS.  Alias is added in favor of
upcoming jsonpath .datetime() method.  But it's also supported in to_date()/
to_timestamp() as positive side effect.
 
Discussion: https://postgr.es/m/CAPpHfdsZgYEra_PeCLGNoXOWYx6iU-S3wF8aX0ObQUcZU%2B4XTw%40mail.gmail.com
Author: Nikita Glukhov, Alexander Korotkov

and second one:

Support for FF1-FF6 datetime format patterns
 
SQL Standard 2016 defines FF1-FF9 format patters for fractions of seconds in
jsonpath .datetime() method and CAST (... FORMAT ...) SQL clause.  Parsing
engine of upcoming .datetime() method will be shared with to_date()/
to_timestamp().
 
This patch implements FF1-FF6 format patterns for upcoming jsonpath .datetime()
method.  to_date()/to_timestamp() functions will also get support of this
format patterns as positive side effect.  FF7-FF9 are not supported due to
lack of precision in our internal timestamp representation.
 
Extracted from original patch by Nikita Glukhov, Teodor Sigaev, Oleg Bartunov.
Heavily revised by me.
 
Discussion: https://postgr.es/m/-b497-f39a-923d-%402ndQuadrant.com
Discussion: https://postgr.es/m/CAPpHfdsZgYEra_PeCLGNoXOWYx6iU-S3wF8aX0ObQUcZU%2B4XTw%40mail.gmail.com
Author: Nikita Glukhov, Teodor Sigaev, Oleg Bartunov, Alexander Korotkov

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Waiting for PostgreSQL 13 – Add support for –jobs in reindexdb

On 27th of July 2019, Michael Paquier committed patch:

Add support for --jobs in reindexdb
 
When doing a schema-level or a database-level operation, a list of
relations to build is created which gets processed in parallel using
multiple connections, based on the recent refactoring for parallel slots
in src/bin/scripts/.  System catalogs are processed first in a
serialized fashion to prevent deadlocks, followed by the rest done in
parallel.
 
This new option is not compatible with --system as reindexing system
catalogs in parallel can lead to deadlocks, and with --index as there is
no conflict handling for indexes rebuilt in parallel depending in the
same relation.
 
Author: Julien Rouhaud
 
Discussion: https://postgr.es/m/CAOBaU_YrnH_Jqo46NhaJ7uRBiWWEcS40VNRQxgFbqYo9kApUsg@mail.gmail.com

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