Previously we were piggybacking on transaction ID parameters to freeze
multixacts; but since there isn't necessarily any relationship between
rates of Xid and multixact consumption, this turns out not to be a good
idea.
Therefore, we now have multixact-specific freezing parameters:
vacuum_multixact_freeze_min_age: when to remove multis as we come across
them in vacuum (default to 5 million, i.e. early in comparison to Xid's
default of 50 million)
vacuum_multixact_freeze_table_age: when to force whole-table scans
instead of scanning only the pages marked as not all visible in
visibility map (default to 150 million, same as for Xids). Whichever of
both which reaches the 150 million mark earlier will cause a whole-table
scan.
autovacuum_multixact_freeze_max_age: when for cause emergency,
uninterruptible whole-table scans (default to 400 million, double as
that for Xids). This means there shouldn't be more frequent emergency
vacuuming than previously, unless multixacts are being used very
rapidly.
Backpatch to 9.3 where multixacts were made to persist enough to require
freezing. To avoid an ABI break in 9.3, VacuumStmt has a couple of
fields in an unnatural place, and StdRdOptions is split in two so that
the newly added fields can go at the end.
Patch by me, reviewed by Robert Haas, with additional input from Andres
Freund and Tom Lane.
We have a practice of providing a "bread crumb" trail between the minor
versions where the migration section actually tells you to do something.
Historically that was just plain text, eg, "see the release notes for
9.2.4"; but if you're using a browser or PDF reader, it's a lot nicer
if it's a live hyperlink. So use "<xref>" instead. Any argument against
doing this vanished with the recent decommissioning of plain-text release
notes.
Vik Fearing
Providing this information as plain text was doubtless worth the trouble
ten years ago, but it seems likely that hardly anyone reads it in this
format anymore. And the effort required to maintain these files (in the
form of extra-complex markup rules in the relevant parts of the SGML
documentation) is significant. So, let's stop doing that and rely solely
on the other documentation formats.
Per discussion, the plain-text INSTALL instructions might still be worth
their keep, so we continue to generate that file.
Rather than remove HISTORY and src/test/regress/README from distribution
tarballs entirely, replace them with simple stub files that tell the reader
where to find the relevant documentation. This is mainly to avoid possibly
breaking packaging recipes that expect these files to exist.
Back-patch to all supported branches, because simplifying the markup
requirements for release notes won't help much unless we do it in all
branches.
Replication slots are a crash-safe data structure which can be created
on either a master or a standby to prevent premature removal of
write-ahead log segments needed by a standby, as well as (with
hot_standby_feedback=on) pruning of tuples whose removal would cause
replication conflicts. Slots have some advantages over existing
techniques, as explained in the documentation.
In a few places, we refer to the type of replication slots introduced
by this patch as "physical" slots, because forthcoming patches for
logical decoding will also have slots, but with somewhat different
properties.
Andres Freund and Robert Haas
New checks include input, month/day/time internal adjustments, addition,
subtraction, multiplication, and negation. Also adjust docs to
correctly specify interval size in bytes.
Report from Rok Kralj
This doesn't work for prepared queries, but it's not too easy to get
the information in that case and there's some debate as to exactly
what the right thing to measure is, so just do this for now.
Andreas Karlsson, with slight doc changes by me.
This patch adds an option, huge_tlb_pages, which allows requesting the
shared memory segment to be allocated using huge pages, by using the
MAP_HUGETLB flag in mmap(). This can improve performance.
The default is 'try', which means that we will attempt using huge pages,
and fall back to non-huge pages if it doesn't work. Currently, only Linux
has MAP_HUGETLB. On other platforms, the default 'try' behaves the same as
'off'.
In the passing, don't try to round the mmap() size to a multiple of
pagesize. mmap() doesn't require that, and there's no particular reason for
PostgreSQL to do that either. When using MAP_HUGETLB, however, round the
request size up to nearest 2MB boundary. This is to work around a bug in
some Linux kernel versions, but also to avoid wasting memory, because the
kernel will round the size up anyway.
Many people were involved in writing this patch, including Christian Kruse,
Richard Poole, Abhijit Menon-Sen, reviewed by Peter Geoghegan, Andres Freund
and me.
json_build_array() and json_build_object allow for the construction of
arbitrarily complex json trees. json_object() turns a one or two
dimensional array, or two separate arrays, into a json_object of
name/value pairs, similarly to the hstore() function.
json_object_agg() aggregates its two arguments into a single json object
as name value pairs.
Catalog version bumped.
Andrew Dunstan, reviewed by Marko Tiikkaja.
This change allows us to eliminate the previous limit on stored query
length, and it makes the shared-memory hash table very much smaller,
allowing more statements to be tracked. (The default value of
pg_stat_statements.max is therefore increased from 1000 to 5000.)
In typical scenarios, the hash table can be large enough to hold all the
statements commonly issued by an application, so that there is little
"churn" in the set of tracked statements, and thus little need to do I/O
to the file.
To further reduce the need for I/O to the query-texts file, add a way
to retrieve all the columns of the pg_stat_statements view except for
the query text column. This is probably not of much interest for human
use but it could be exploited by programs, which will prefer using the
queryid anyway.
Ordinarily, we'd need to bump the extension version number for the latter
change. But since we already advanced pg_stat_statements' version number
from 1.1 to 1.2 in the 9.4 development cycle, it seems all right to just
redefine what 1.2 means.
Peter Geoghegan, reviewed by Pavel Stehule
This makes it possible to store lwlocks as part of some other data
structure in the main shared memory segment, or in a dynamic shared
memory segment. There is still a main LWLock array and this patch does
not move anything out of it, but it provides necessary infrastructure
for doing that in the future.
This change is likely to increase the size of LWLockPadded on some
platforms, especially 32-bit platforms where it was previously only
16 bytes.
Patch by me. Review by Andres Freund and KaiGai Kohei.
Fix integer overflow issue noted by Magnus Hagander, as well as a bunch
of other infelicities in commit ee1e5662d8
and its unreasonably large number of followups.
From the Department of Nitpicking, be consistent with other escaping
and use 'E' instead of 'e' to escape the string in the example docs
for GET DISAGNOSTICS stack = PG_CONTEXT.
Noticed by Department Chief Magnus Hagander.
Mention that CREATE TABLE LIKE INCLUDING DEFAULTS creates a link between
the original and new tables if a default function modifies the database,
like nextval().
This allows ending recovery as a consistent state has been reached. Without
this, there was no easy way to e.g restore an online backup, without
replaying any extra WAL after the backup ended.
MauMau and me.
Add the ability to specify the objects to move by who those objects are
owned by (as relowner) and change ALL to mean ALL objects. This
makes the command always operate against a well-defined set of objects
and not have the objects-to-be-moved based on the role of the user
running the command.
Per discussion with Simon and Tom.
There was a bug in the psql's meta command \conninfo. When the
IP address was specified in the hostaddr and psql used it to create
a connection (i.e., psql -d "hostaddr=xxx"), \conninfo could not
display that address. This is because \conninfo got the connection
information only from PQhost() which could not return hostaddr.
This patch adds PQhostaddr(), and changes \conninfo so that it
can display not only the host name that PQhost() returns but also
the IP address which PQhostaddr() returns.
The bug has existed since 9.1 where \conninfo was introduced.
But it's too late to add new libpq function into the released versions,
so no backpatch.
Alvaro Herrera