Author: depesz

Waiting for 9.5 – Implement IMPORT FOREIGN SCHEMA.

On 10th of July, Tom Lane committed patch:

Implement IMPORT FOREIGN SCHEMA.
 
This command provides an automated way to create foreign table definitions
that match remote tables, thereby reducing tedium and chances for error.
In this patch, we provide the necessary core-server infrastructure and
implement the feature fully in the postgres_fdw foreign-data wrapper.
Other wrappers will throw a "feature not supported" error until/unless
they are updated.
 
Ronan Dunklau and Michael Paquier, additional work by me

Continue reading Waiting for 9.5 – Implement IMPORT FOREIGN SCHEMA.

Waiting for 9.5 – Add cluster_name GUC which is included in process titles if set.

On 29th of June, Andres Freund committed patch:

Add cluster_name GUC which is included in process titles if set.
 
When running several postgres clusters on one OS instance it's often
inconveniently hard to identify which "postgres" process belongs to
which postgres instance.
 
Add the cluster_name GUC, whose value will be included as part of the
process titles if set. With that processes can more easily identified
using tools like 'ps'.
 
To avoid problems with encoding mismatches between postgresql.conf,
consoles, and individual databases replace non-ASCII chars in the name
with question marks. The length is limited to NAMEDATALEN to make it
less likely to truncate important information at the end of the
status.
 
Thomas Munro, with some adjustments by me and review by a host of people.

Continue reading Waiting for 9.5 – Add cluster_name GUC which is included in process titles if set.

Waiting for 9.5 – Implement UPDATE tab SET (col1,col2,…) = (SELECT …), …

On 18th of June, Tom Lane committed patch:

Implement UPDATE tab SET (col1,col2,...) = (SELECT ...), ...
 
This SQL-standard feature allows a sub-SELECT yielding multiple columns
(but only one row) to be used to compute the new values of several columns
to be updated.  While the same results can be had with an independent
sub-SELECT per column, such a workaround can require a great deal of
duplicated computation.
 
The standard actually says that the source for a multi-column assignment
could be any row-valued expression.  The implementation used here is
tightly tied to our existing sub-SELECT support and can't handle other
cases; the Bison grammar would have some issues with them too.  However,
I don't feel too bad about this since other cases can be converted into
sub-SELECTs.  For instance, "SET (a,b,c) = row_valued_function(x)" could
be written "SET (a,b,c) = (SELECT * FROM row_valued_function(x))".

Continue reading Waiting for 9.5 – Implement UPDATE tab SET (col1,col2,…) = (SELECT …), …

Anonymize CTE names on explain.depesz.com

A colleague recently let me know that anonymization in explain.depesz.com doesn't handle CTE names. For example, in plan:

                                            QUERY PLAN                                             
---------------------------------------------------------------------------------------------------
 CTE Scan ON some_name  (cost=0.01..0.03 ROWS=1 width=8) (actual TIME=0.027..0.028 ROWS=1 loops=1)
   CTE some_name
     ->  RESULT  (cost=0.00..0.01 ROWS=1 width=0) (actual TIME=0.023..0.023 ROWS=1 loops=1)
 Planning TIME: 0.217 ms
 Execution TIME: 0.124 ms
(5 ROWS)

“some_name" was kept even if anonymization was turned on.

Now it's fixed, and new code should properly anonymize all CTE names. Of course the change is live on explain.depesz.com too.

Waiting for 9.4 – Add support for wrapping to psql’s “extended” mode.

On 28th of April, Greg Stark committed patch:

Add support for wrapping to psql's "extended" mode. This makes it very
 
feasible to display tables that have both many columns and some large
data in some columns (such as pg_stats).
 
Emre Hasegeli with review and rewriting from Sergey Muraviov and
reviewed by Greg Stark

Continue reading Waiting for 9.4 – Add support for wrapping to psql's “extended" mode.

Waiting for 9.4 – Provide moving-aggregate support for a bunch of aggregates.

On 13th of April, Tom Lane committed patch:

Provide moving-aggregate support for a bunch of numerical aggregates.
 
First installment of the promised moving-aggregate support in built-in
aggregates: count(), sum(), avg(), stddev() and variance() for
assorted datatypes, though not for float4/float8.
 
In passing, remove a 2001-vintage kluge in interval_accum(): interval
array elements have been properly aligned since around 2003, but
nobody remembered to take out this workaround.  Also, fix a thinko
in the opr_sanity tests for moving-aggregate catalog entries.
 
David Rowley and Florian Pflug, reviewed by Dean Rasheed

On the same day he also committed:

Provide moving-aggregate support for boolean aggregates.
 
David Rowley and Florian Pflug, reviewed by Dean Rasheed

Continue reading Waiting for 9.4 – Provide moving-aggregate support for a bunch of aggregates.

How to deal with timestamps?

Every now and then someone asks, on irc or mailing lists, some question which shows deep misunerstanding (or lack of understanding) of timestamps – especially the ones with time zones.

Since I got bitten by this before, let me describe what timestamps are, how to work with them, and what are the most common pitfalls that you can encounter.

Continue reading How to deal with timestamps?

Waiting for 9.4 – Introduce jsonb, a structured format for storing json.

Portuguese Brazil Version

On 23rd of March, Andrew Dunstan committed patch:

Introduce jsonb, a structured format for storing json.
 
The new format accepts exactly the same data as the json type. However, it is
stored in a format that does not require reparsing the orgiginal text in order
to process it, making it much more suitable for indexing and other operations.
Insignificant whitespace is discarded, and the order of object keys is not
preserved. Neither are duplicate object keys kept - the later value for a given
key is the only one stored.
 
The new type has all the functions and operators that the json type has,
with the exception of the json generation functions (to_json, json_agg etc.)
and with identical semantics. In addition, there are operator classes for
hash and btree indexing, and two classes for GIN indexing, that have no
equivalent in the json type.
 
This feature grew out of previous work by Oleg Bartunov and Teodor Sigaev, which
was intended to provide similar facilities to a nested hstore type, but which
in the end proved to have some significant compatibility issues.
 
Authors: Oleg Bartunov,  Teodor Sigaev, Peter Geoghegan and Andrew Dunstan.
Review: Andres Freund

Continue reading Waiting for 9.4 – Introduce jsonb, a structured format for storing json.