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b60a8512a0
< BY col {DESC} LIMIT 1. Completing this item involves making this
> BY col {DESC} LIMIT 1. Completing this item involves doing this
< invalidated if anyone modifies the table.
<
> invalidated if anyone modifies the table. Another idea is to
> get a count directly from a unique index, but for this to be
> faster than a sequential scan it must avoid access to the heap
> to obtain tuple visibility information.
>
> * Allow data to be pulled directly from indexes
>
> Currently indexes do not have enough tuple tuple visibility
> information to allow data to be pulled from the index without
> also accessing the heap. One way to allow this is to set a bit
> to index tuples to indicate if a tuple is currently visible to
> all transactions when the first valid heap lookup happens. This
> bit would have to be cleared when a heap tuple is expired.
>
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| config | ||
| contrib | ||
| doc | ||
| src | ||
| aclocal.m4 | ||
| configure | ||
| configure.in | ||
| COPYRIGHT | ||
| GNUmakefile.in | ||
| Makefile | ||
| README | ||
| README.CVS | ||
PostgreSQL Database Management System ===================================== This directory contains the source code distribution of the PostgreSQL database management system. PostgreSQL is an advanced object-relational database management system that supports an extended subset of the SQL standard, including transactions, foreign keys, subqueries, triggers, user-defined types and functions. This distribution also contains C language bindings. The JDBC, ODBC, C++, Python, and Tcl interfaces have been moved to the PostgreSQL Projects Web Site at http://gborg.postgresql.org for separate maintenance. A Perl DBI/DBD driver is available from CPAN. See the file INSTALL for instructions on how to build and install PostgreSQL. That file also lists supported operating systems and hardware platforms and contains information regarding any other software packages that are required to build or run the PostgreSQL system. Changes between all PostgreSQL releases are recorded in the file HISTORY. Copyright and license information can be found in the file COPYRIGHT. A comprehensive documentation set is included in this distribution; it can be read as described in the installation instructions. The latest version of this software may be obtained at ftp://ftp.postgresql.org/pub/. For more information look at our web site located at http://www.postgresql.org/.