On 18th of March, Alvaro Herrera committed patch:
array_offset() and array_offsets() These functions return the offset position or positions of a value in an array. Author: Pavel Stěhule Reviewed by: Jim Nasby
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On 23rd of February, Heikki Linnakangas committed patch:
Replace checkpoint_segments with min_wal_size and max_wal_size. Instead of having a single knob (checkpoint_segments) that both triggers checkpoints, and determines how many checkpoints to recycle, they are now separate concerns. There is still an internal variable called CheckpointSegments, which triggers checkpoints. But it no longer determines how many segments to recycle at a checkpoint. That is now auto-tuned by keeping a moving average of the distance between checkpoints (in bytes), and trying to keep that many segments in reserve. The advantage of this is that you can set max_wal_size very high, but the system won't actually consume that much space if there isn't any need for it. The min_wal_size sets a floor for that; you can effectively disable the auto-tuning behavior by setting min_wal_size equal to max_wal_size. The max_wal_size setting is now the actual target size of WAL at which a new checkpoint is triggered, instead of the distance between checkpoints. Previously, you could calculate the actual WAL usage with the formula "(2 + checkpoint_completion_target) * checkpoint_segments + 1". With this patch, you set the desired WAL usage with max_wal_size, and the system calculates the appropriate CheckpointSegments with the reverse of that formula. That's a lot more intuitive for administrators to set. Reviewed by Amit Kapila and Venkata Balaji N.
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On 19th of January, Robert Haas committed patch:
Use abbreviated keys for faster sorting of text datums. This commit extends the SortSupport infrastructure to allow operator classes the option to provide abbreviated representations of Datums; in the case of text, we abbreviate by taking the first few characters of the strxfrm() blob. If the abbreviated comparison is insufficent to resolve the comparison, we fall back on the normal comparator. This can be much faster than the old way of doing sorting if the first few bytes of the string are usually sufficient to resolve the comparison. There is the potential for a performance regression if all of the strings to be sorted are identical for the first 8+ characters and differ only in later positions; therefore, the SortSupport machinery now provides an infrastructure to abort the use of abbreviation if it appears that abbreviation is producing comparatively few distinct keys. HyperLogLog, a streaming cardinality estimator, is included in this commit and used to make that determination for text. Peter Geoghegan, reviewed by me.
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On 23rd of January, Alvaro Herrera committed patch:
vacuumdb: enable parallel mode This mode allows vacuumdb to open several server connections to vacuum or analyze several tables simultaneously. Author: Dilip Kumar. Some reworking by Álvaro Herrera Reviewed by: Jeff Janes, Amit Kapila, Magnus Hagander, Andres Freund
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On 15th of December, Heikki Linnakangas committed patch:
Add point <-> polygon distance operator. Alexander Korotkov, reviewed by Emre Hasegeli.
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On 8th of December, Simon Riggs committed patch:
REINDEX SCHEMA Add new SCHEMA option to REINDEX and reindexdb. Sawada Masahiko Reviewed by Michael Paquier and Fabrízio de Royes Mello
On 7th of December, Simon Riggs committed patch:
Event Trigger for table_rewrite Generate a table_rewrite event when ALTER TABLE attempts to rewrite a table. Provide helper functions to identify table and reason. Intended use case is to help assess or to react to schema changes that might hold exclusive locks for long periods. Dimitri Fontaine, triggering an edit by Simon Riggs Reviewed in detail by Michael Paquier
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On 25th of November, Tom Lane committed patch:
Support arrays as input to array_agg() and ARRAY(SELECT ...). These cases formerly failed with errors about "could not find array type for data type". Now they yield arrays of the same element type and one higher dimension. The implementation involves creating functions with API similar to the existing accumArrayResult() family. I (tgl) also extended the base family by adding an initArrayResult() function, which allows callers to avoid special-casing the zero-inputs case if they just want an empty array as result. (Not all do, so the previous calling convention remains valid.) This allowed simplifying some existing code in xml.c and plperl.c. Ali Akbar, reviewed by Pavel Stehule, significantly modified by me
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On 11th of November, Fujii Masao committed patch:
Add generate_series(numeric, numeric). Платон Малюгин Reviewed by Michael Paquier, Ali Akbar and Marti Raudsepp
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On 7th of November, Alvaro Herrera committed patch:
BRIN is a new index access method intended to accelerate scans of very large tables, without the maintenance overhead of btrees or other traditional indexes. They work by maintaining "summary" data about block ranges. Bitmap index scans work by reading each summary tuple and comparing them with the query quals; all pages in the range are returned in a lossy TID bitmap if the quals are consistent with the values in the summary tuple, otherwise not. Normal index scans are not supported because these indexes do not store TIDs. As new tuples are added into the index, the summary information is updated (if the block range in which the tuple is added is already summarized) or not; in the latter case, a subsequent pass of VACUUM or the brin_summarize_new_values() function will create the summary information. For data types with natural 1-D sort orders, the summary info consists of the maximum and the minimum values of each indexed column within each page range. This type of operator class we call "Minmax", and we supply a bunch of them for most data types with B-tree opclasses. Since the BRIN code is generalized, other approaches are possible for things such as arrays, geometric types, ranges, etc; even for things such as enum types we could do something different than minmax with better results. In this commit I only include minmax. Catalog version bumped due to new builtin catalog entries. There's more that could be done here, but this is a good step forwards. Loosely based on ideas from Simon Riggs; code mostly by Álvaro Herrera, with contribution by Heikki Linnakangas. Patch reviewed by: Amit Kapila, Heikki Linnakangas, Robert Haas. Testing help from Jeff Janes, Erik Rijkers, Emanuel Calvo. PS: The research leading to these results has received funding from the European Union's Seventh Framework Programme (FP7/2007-2013) under grant agreement n° 318633.
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