When calling sort_expanded_ranges() we need to remember the return
value, because the function sorts and also deduplicates the ranges. So
the number of ranges may decrease. brin_minmax_multi_union failed to do
that, which resulted in crashes due to bogus ranges (equal minval/maxval
but not marked as compacted).
Reported-by: Jaime Casanova
Discussion: https://postgr.es/m/20210404052550.GA4376%40ahch-to
The BRIN minmax-multi consistent function incorrectly assumed it can
lookup an operator, and then swap the arguments to get the commutator.
For example <(a,b) would be called as <(b,a) to get >(a,b). This works
when the arguments are of the same type, but with cross-type opclasses
this fails. We can't swap <(float4,float8) arguments, for example.
Fixed by passing arguments in the right order.
Discussion: https://postgr.es/m/CAJKUy5jLZFLCxyxfT%3DMfK5mtPfSzHA1rVLowR-j4RRsFVvKm7A%40mail.gmail.com
The distance calculation ignored the mask, unlike the inet comparator,
which resulted in negative distance in some cases. Fixed by applying the
mask in brin_minmax_multi_distance_inet. I've considered simply calling
inetmi() to calculate the delta, but that does not consider mask either.
Reviewed-by: Zhihong Yu
Discussion: https://postgr.es/m/1a0a7b9d-9bda-e3a2-7fa4-88f15042a051%40enterprisedb.com
The distance calculation for interval type was treating months as having
31 days, which is inconsistent with the interval comparator (using 30
days). Due to this it was possible to get negative distance (b-a) when
(a<b), trigerring an assert.
Fixed by adopting the same logic as interval_cmp_value.
Reported-by: Jaime Casanova
Discussion: https://postgr.es/m/CAJKUy5jKH0Xhneau2mNftNPtTy-BVgQfXc8zQkEvRvBHfeUThQ%40mail.gmail.com
The deserialization failed to ensure correct alignment, as it assumed it
can simply point into the serialized value. The serialization however
ignores alignment and copies just the significant bytes in order to make
the result as small as possible. This caused failures on systems that
are sensitive to mialigned addresses, like sparc, or with address
sanitizer enabled.
Fixed by copying the serialized data to ensure proper alignment. While
at it, fix an issue with serialization on big endian machines, using the
same store_att_byval/fetch_att trick as extended statistics.
Discussion: https://postgr.es/0c8c3304-d3dd-5e29-d5ac-b50589a23c8c%40enterprisedb.com
Adds BRIN opclasses similar to the existing minmax, except that instead
of summarizing the page range into a single [min,max] range, the summary
consists of multiple ranges and/or points, allowing gaps. This allows
more efficient handling of data with poor correlation to physical
location within the table and/or outlier values, for which the regular
minmax opclassed tend to work poorly.
It's possible to specify the number of values kept for each page range,
either as a single point or an interval boundary.
CREATE TABLE t (a int);
CREATE INDEX ON t
USING brin (a int4_minmax_multi_ops(values_per_range=16));
When building the summary, the values are combined into intervals with
the goal to minimize the "covering" (sum of interval lengths), using a
support procedure computing distance between two values.
Bump catversion, due to various catalog changes.
Author: Tomas Vondra <tomas.vondra@postgresql.org>
Reviewed-by: Alvaro Herrera <alvherre@alvh.no-ip.org>
Reviewed-by: Alexander Korotkov <aekorotkov@gmail.com>
Reviewed-by: Sokolov Yura <y.sokolov@postgrespro.ru>
Reviewed-by: John Naylor <john.naylor@enterprisedb.com>
Discussion: https://postgr.es/m/c1138ead-7668-f0e1-0638-c3be3237e812@2ndquadrant.com
Discussion: https://postgr.es/m/5d78b774-7e9c-c94e-12cf-fef51cc89b1a%402ndquadrant.com
