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a4d75c86bf
Allow defining extended statistics on expressions, not just just on
simple column references. With this commit, expressions are supported
by all existing extended statistics kinds, improving the same types of
estimates. A simple example may look like this:
CREATE TABLE t (a int);
CREATE STATISTICS s ON mod(a,10), mod(a,20) FROM t;
ANALYZE t;
The collected statistics are useful e.g. to estimate queries with those
expressions in WHERE or GROUP BY clauses:
SELECT * FROM t WHERE mod(a,10) = 0 AND mod(a,20) = 0;
SELECT 1 FROM t GROUP BY mod(a,10), mod(a,20);
This introduces new internal statistics kind 'e' (expressions) which is
built automatically when the statistics object definition includes any
expressions. This represents single-expression statistics, as if there
was an expression index (but without the index maintenance overhead).
The statistics is stored in pg_statistics_ext_data as an array of
composite types, which is possible thanks to 79f6a942bd.
CREATE STATISTICS allows building statistics on a single expression, in
which case in which case it's not possible to specify statistics kinds.
A new system view pg_stats_ext_exprs can be used to display expression
statistics, similarly to pg_stats and pg_stats_ext views.
ALTER TABLE ... ALTER COLUMN ... TYPE now treats indexes the same way it
treats indexes, i.e. it drops and recreates the statistics. This means
all statistics are reset, and we no longer try to preserve at least the
functional dependencies. This should not be a major issue in practice,
as the functional dependencies actually rely on per-column statistics,
which were always reset anyway.
Author: Tomas Vondra
Reviewed-by: Justin Pryzby, Dean Rasheed, Zhihong Yu
Discussion: https://postgr.es/m/ad7891d2-e90c-b446-9fe2-7419143847d7%40enterprisedb.com
141 lines
5.4 KiB
Makefile
141 lines
5.4 KiB
Makefile
#-------------------------------------------------------------------------
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#
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# Makefile for backend/catalog
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#
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# Portions Copyright (c) 1996-2021, PostgreSQL Global Development Group
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# Portions Copyright (c) 1994, Regents of the University of California
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#
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# src/backend/catalog/Makefile
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#
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#-------------------------------------------------------------------------
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subdir = src/backend/catalog
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top_builddir = ../../..
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include $(top_builddir)/src/Makefile.global
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OBJS = \
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aclchk.o \
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catalog.o \
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dependency.o \
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heap.o \
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index.o \
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indexing.o \
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namespace.o \
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objectaccess.o \
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objectaddress.o \
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partition.o \
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pg_aggregate.o \
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pg_cast.o \
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pg_collation.o \
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pg_constraint.o \
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pg_conversion.o \
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pg_db_role_setting.o \
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pg_depend.o \
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pg_enum.o \
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pg_inherits.o \
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pg_largeobject.o \
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pg_namespace.o \
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pg_operator.o \
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pg_proc.o \
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pg_publication.o \
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pg_range.o \
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pg_shdepend.o \
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pg_subscription.o \
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pg_type.o \
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storage.o \
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toasting.o
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include $(top_srcdir)/src/backend/common.mk
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# Note: the order of this list determines the order in which the catalog
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# header files are assembled into postgres.bki. BKI_BOOTSTRAP catalogs
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# must appear first, and pg_statistic before pg_statistic_ext_data, and
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# there are reputedly other, undocumented ordering dependencies.
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CATALOG_HEADERS := \
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pg_proc.h pg_type.h pg_attribute.h pg_class.h \
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pg_attrdef.h pg_constraint.h pg_inherits.h pg_index.h pg_operator.h \
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pg_opfamily.h pg_opclass.h pg_am.h pg_amop.h pg_amproc.h \
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pg_language.h pg_largeobject_metadata.h pg_largeobject.h pg_aggregate.h \
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pg_statistic.h pg_statistic_ext.h pg_statistic_ext_data.h \
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pg_rewrite.h pg_trigger.h pg_event_trigger.h pg_description.h \
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pg_cast.h pg_enum.h pg_namespace.h pg_conversion.h pg_depend.h \
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pg_database.h pg_db_role_setting.h pg_tablespace.h \
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pg_authid.h pg_auth_members.h pg_shdepend.h pg_shdescription.h \
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pg_ts_config.h pg_ts_config_map.h pg_ts_dict.h \
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pg_ts_parser.h pg_ts_template.h pg_extension.h \
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pg_foreign_data_wrapper.h pg_foreign_server.h pg_user_mapping.h \
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pg_foreign_table.h pg_policy.h pg_replication_origin.h \
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pg_default_acl.h pg_init_privs.h pg_seclabel.h pg_shseclabel.h \
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pg_collation.h pg_partitioned_table.h pg_range.h pg_transform.h \
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pg_sequence.h pg_publication.h pg_publication_rel.h pg_subscription.h \
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pg_subscription_rel.h
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GENERATED_HEADERS := $(CATALOG_HEADERS:%.h=%_d.h) schemapg.h system_fk_info.h
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POSTGRES_BKI_SRCS := $(addprefix $(top_srcdir)/src/include/catalog/, $(CATALOG_HEADERS))
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# The .dat files we need can just be listed alphabetically.
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POSTGRES_BKI_DATA = $(addprefix $(top_srcdir)/src/include/catalog/,\
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pg_aggregate.dat pg_am.dat pg_amop.dat pg_amproc.dat pg_authid.dat \
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pg_cast.dat pg_class.dat pg_collation.dat pg_conversion.dat \
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pg_database.dat pg_language.dat \
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pg_namespace.dat pg_opclass.dat pg_operator.dat pg_opfamily.dat \
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pg_proc.dat pg_range.dat pg_tablespace.dat \
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pg_ts_config.dat pg_ts_config_map.dat pg_ts_dict.dat pg_ts_parser.dat \
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pg_ts_template.dat pg_type.dat \
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)
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all: distprep generated-header-symlinks
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distprep: bki-stamp
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.PHONY: generated-header-symlinks
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generated-header-symlinks: $(top_builddir)/src/include/catalog/header-stamp
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# bki-stamp records the last time we ran genbki.pl. We don't rely on
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# the timestamps of the individual output files, because the Perl script
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# won't update them if they didn't change (to avoid unnecessary recompiles).
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# Technically, this should depend on Makefile.global which supplies
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# $(MAJORVERSION); but then genbki.pl would need to be re-run after every
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# configure run, even in distribution tarballs. So depending on configure.ac
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# instead is cheating a bit, but it will achieve the goal of updating the
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# version number when it changes.
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bki-stamp: genbki.pl Catalog.pm $(POSTGRES_BKI_SRCS) $(POSTGRES_BKI_DATA) $(top_srcdir)/configure.ac
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$(PERL) $< --include-path=$(top_srcdir)/src/include/ \
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--set-version=$(MAJORVERSION) $(POSTGRES_BKI_SRCS)
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touch $@
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# The generated headers must all be symlinked into builddir/src/include/,
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# using absolute links for the reasons explained in src/backend/Makefile.
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# We use header-stamp to record that we've done this because the symlinks
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# themselves may appear older than bki-stamp.
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$(top_builddir)/src/include/catalog/header-stamp: bki-stamp
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prereqdir=`cd '$(dir $<)' >/dev/null && pwd` && \
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cd '$(dir $@)' && for file in $(GENERATED_HEADERS); do \
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rm -f $$file && $(LN_S) "$$prereqdir/$$file" . ; \
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done
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touch $@
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# Note: installation of generated headers is handled elsewhere
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.PHONY: install-data
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install-data: bki-stamp installdirs
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$(INSTALL_DATA) $(call vpathsearch,postgres.bki) '$(DESTDIR)$(datadir)/postgres.bki'
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$(INSTALL_DATA) $(call vpathsearch,system_constraints.sql) '$(DESTDIR)$(datadir)/system_constraints.sql'
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$(INSTALL_DATA) $(srcdir)/system_views.sql '$(DESTDIR)$(datadir)/system_views.sql'
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$(INSTALL_DATA) $(srcdir)/information_schema.sql '$(DESTDIR)$(datadir)/information_schema.sql'
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$(INSTALL_DATA) $(srcdir)/sql_features.txt '$(DESTDIR)$(datadir)/sql_features.txt'
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installdirs:
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$(MKDIR_P) '$(DESTDIR)$(datadir)'
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.PHONY: uninstall-data
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uninstall-data:
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rm -f $(addprefix '$(DESTDIR)$(datadir)'/, postgres.bki system_constraints.sql system_views.sql information_schema.sql sql_features.txt)
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# postgres.bki, system_constraints.sql, and the generated headers are
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# in the distribution tarball, so they are not cleaned here.
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clean:
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maintainer-clean: clean
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rm -f bki-stamp postgres.bki system_constraints.sql $(GENERATED_HEADERS)
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