Waiting for PostgreSQL 10 – Support SCRAM-SHA-256 authentication (RFC 5802 and 7677).

On 7th of March 2017, Heikki Linnakangas committed patch:

Support SCRAM-SHA-256 authentication (RFC 5802 and 7677).
 
 
This introduces a new generic SASL authentication method, similar to the
GSS and SSPI methods. The server first tells the client which SASL
authentication mechanism to use, and then the mechanism-specific SASL
messages are exchanged in AuthenticationSASLcontinue and PasswordMessage
messages. Only SCRAM-SHA-256 is supported at the moment, but this allows
adding more SASL mechanisms in the future, without changing the overall
protocol.
 
Support for channel binding, aka SCRAM-SHA-256-PLUS is left for later.
 
The SASLPrep algorithm, for pre-processing the password, is not yet
implemented. That could cause trouble, if you use a password with
non-ASCII characters, and a client library that does implement SASLprep.
That will hopefully be added later.
 
Authorization identities, as specified in the SCRAM-SHA-256 specification,
are ignored. SET SESSION AUTHORIZATION provides more or less the same
functionality, anyway.
 
If a user doesn't exist, perform a "mock" authentication, by constructing
an authentic-looking challenge on the fly. The challenge is derived from
a new system-wide random value, "mock authentication nonce", which is
created at initdb, and stored in the control file. We go through these
motions, in order to not give away the information on whether the user
exists, to unauthenticated users.
 
Bumps PG_CONTROL_VERSION, because of the new field in control file.
 
Patch by Michael Paquier and Heikki Linnakangas, reviewed at different
stages by Robert Haas, Stephen Frost, David Steele, Aleksander Alekseev,
and many others.
 
Discussion: https://www.postgresql.org/message-id/CAB7nPqRbR3GmFYdedCAhzukfKrgBLTLtMvENOmPrVWREsZkF8g%40mail.gmail.com
Discussion: https://www.postgresql.org/message-id/CAB7nPqSMXU35g%3DW9X74HVeQp0uvgJxvYOuA4A-A3M%2B0wfEBv-w%40mail.gmail.com
Discussion: https://www.postgresql.org/message-id/.6080106@iki.fi

Continue reading Waiting for PostgreSQL 10 – Support SCRAM-SHA-256 authentication (RFC 5802 and 7677).

Waiting for PostgreSQL 10 – Identity columns

On 6th of April 2017, Peter Eisentraut committed patch:

Identity columns
 
This is the SQL standard-conforming variant of PostgreSQL's serial
columns.  It fixes a few usability issues that serial columns have:
 
- CREATE TABLE / LIKE copies default but refers to same sequence
- cannot add/drop serialness with ALTER TABLE
- dropping default does not drop sequence
- need to grant separate privileges to sequence
- other slight weirdnesses because serial is some kind of special macro

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Waiting for PostgreSQL 10 – Full Text Search support for json and jsonb

On 31st of March 2017, Andrew Dunstan committed patch:

Full Text Search support for json and jsonb
 
The new functions are ts_headline() and to_tsvector.
 
Dmitry Dolgov, edited and documented by me.

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Waiting for PostgreSQL 10 – Support \if … \elif … \else … \endif in psql scripting.

On 30th of March 2017, Tom Lane committed patch:

Support \if ... \elif ... \else ... \endif in psql scripting.
 
This patch adds nestable conditional blocks to psql.  The control
structure feature per se is complete, but the boolean expressions
understood by \if and \elif are pretty primitive; basically, after
variable substitution and backtick expansion, the result has to be
"true" or "false" or one of the other standard spellings of a boolean
value.  But that's enough for many purposes, since you can always
do the heavy lifting on the server side; and we can extend it later.
 
Along the way, pay down some of the technical debt that had built up
around psql/command.c:
* Refactor exec_command() into a function per command, instead of
being a 1500-line monstrosity.  This makes the file noticeably longer
because of repetitive function header/trailer overhead, but it seems
much more readable.
* Teach psql_get_variable() and psqlscanslash.l to suppress variable
substitution and backtick expansion on the basis of the conditional
stack state, thereby allowing removal of the OT_NO_EVAL kluge.
* Fix the no-doubt-once-expedient hack of sometimes silently substituting
mainloop.c's previous_buf for query_buf when calling HandleSlashCmds.
(It's a bit remarkable that commands like \r worked at all with that.)
Recall of a previous query is now done explicitly in the slash commands
where that should happen.
 
Corey Huinker, reviewed by Fabien Coelho, further hacking by me
 
Discussion: https://postgr.es/m/CADkLM=c94OSRTnat=LX0ivNq4pxDNeoomFfYvBKM5N_xfmLtAA@mail.gmail.com

Continue reading Waiting for PostgreSQL 10 – Support \if … \elif … \else … \endif in psql scripting.

Waiting for PostgreSQL 10 – Logical replication support for initial data copy

On 23rd of March 2017, Peter Eisentraut committed patch:

Logical replication support for initial data copy
 
Add functionality for a new subscription to copy the initial data in the
tables and then sync with the ongoing apply process.
 
For the copying, add a new internal COPY option to have the COPY source
data provided by a callback function.  The initial data copy works on
the subscriber by receiving COPY data from the publisher and then
providing it locally into a COPY that writes to the destination table.
 
A WAL receiver can now execute full SQL commands.  This is used here to
obtain information about tables and publications.
 
Several new options were added to CREATE and ALTER SUBSCRIPTION to
control whether and when initial table syncing happens.
 
Change pg_dump option --no-create-subscription-slots to
--no-subscription-connect and use the new CREATE SUBSCRIPTION
... NOCONNECT option for that.
 
Author: Petr Jelinek

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Waiting for PostgreSQL 10 – hash indexing vs. WAL

For a long time hash indexed were not crash safe, and couldn't be used on replication slave, because they skipped WAL. Now, thanks to these two commits, it has changed:

On 14th of March 2017, Robert Haas committed patch:

hash: Add write-ahead logging support.
 
The warning about hash indexes not being write-ahead logged and their
use being discouraged has been removed.  "snapshot too old" is now
supported for tables with hash indexes.  Most importantly, barring
bugs, hash indexes will now be crash-safe and usable on standbys.
 
This commit doesn't yet add WAL consistency checking for hash
indexes, as we now have for other index types; a separate patch has
been submitted to cure that lack.
 
Amit Kapila, reviewed and slightly modified by me.  The larger patch
series of which this is a part has been reviewed and tested by Álvaro
Herrera, Ashutosh Sharma, Mark Kirkwood, Jeff Janes, and Jesper
Pedersen.
 
Discussion: http://postgr.es/m/CAA4eK1JOBX=YU33631Qh-XivYXtPSALh514+jR8XeD7v+K3r_Q@mail.gmail.com

and then, ~ 13 hours later, Robert committed also:

hash: Support WAL consistency checking.
 
Kuntal Ghosh, reviewed by Amit Kapila and Ashutosh Sharma, with
a few tweaks by me.
 
Discussion: http://postgr.es/m/CAGz5QCJLERUn_zoO0eDv6_Y_d0o4tNTMPeR7ivTLBg4rUrJdwg@mail.gmail.com

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Waiting for PostgreSQL 10 – Support XMLTABLE query expression

On 8th of March, Alvaro Herrera committed patch:

XMLTABLE is defined by the SQL/XML standard as a feature that allows
turning XML-formatted data into relational form, so that it can be used
as a <table primary> in the FROM clause of a query.
 
This new construct provides significant simplicity and performance
benefit for XML data processing; what in a client-side custom
implementation was reported to take 20 minutes can be executed in 400ms
using XMLTABLE.  (The same functionality was said to take 10 seconds
using nested PostgreSQL XPath function calls, and 5 seconds using
XMLReader under PL/Python).
 
The implemented syntax deviates slightly from what the standard
requires.  First, the standard indicates that the PASSING clause is
optional and that multiple XML input documents may be given to it; we
make it mandatory and accept a single document only.  Second, we don't
currently support a default namespace to be specified.
 
This implementation relies on a new executor node based on a hardcoded
method table.  (Because the grammar is fixed, there is no extensibility
in the current approach; further constructs can be implemented on top of
this such as JSON_TABLE, but they require changes to core code.)
 
Author: Pavel Stehule, Álvaro Herrera
Extensively reviewed by: Craig Ringer
Discussion: https://postgr.es/m/CAFj8pRAgfzMD-LoSmnMGybD0WsEznLHWap8DO79+-GTRAPR4qA@mail.gmail.com

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Waiting for PostgreSQL 10 – psql: Add \gx command

On 7th of March, Stephen Frost committed patch:

psql: Add \gx command
 
It can often be useful to use expanded mode output (\x) for just a
single query.  Introduce a \gx which acts exactly like \g except that it
will force expanded output mode for that one \gx call.  This is simpler
than having to use \x as a toggle and also means that the user doesn't
have to worry about the current state of the expanded variable, or
resetting it later, to ensure a given query is always returned in
expanded mode.
 
Primairly Christoph's patch, though I did tweak the documentation and help
text a bit, and re-indented the tab completion section.
 
Author: Christoph Berg
Reviewed By: Daniel Verite
Discussion: <a href="https://postgr.es/m/20170127132737.6skslelaf4txs6iw%40msg.credativ.de">https://www.postgresql.org/message-id/20170127132737.6skslelaf4txs6iw%40msg.credativ.de

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Waiting for PostgreSQL 10 – Logical replication

On 20th of January, Peter Eisentraut committed patch:

Logical replication
 
- Add PUBLICATION catalogs and DDL
- Add SUBSCRIPTION catalog and DDL
- Define logical replication protocol and output plugin
- Add logical replication workers
 
From: Petr Jelinek
Reviewed-by: Steve Singer
Reviewed-by: Andres Freund
Reviewed-by: Erik Rijkers
Reviewed-by: Peter Eisentraut

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Waiting for PostgreSQL 10 – Add pg_sequence system catalog

On 20th of December, Peter Eisentraut committed patch:

Add pg_sequence system catalog
 
Move sequence metadata (start, increment, etc.) into a proper system
catalog instead of storing it in the sequence heap object.  This
separates the metadata from the sequence data.  Sequence metadata is now
operated on transactionally by DDL commands, whereas previously
rollbacks of sequence-related DDL commands would be ignored.
 
Reviewed-by: Andreas Karlsson

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