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Diffstat (limited to 'doc/FAQ')
| -rw-r--r-- | doc/FAQ | 36 |
1 files changed, 18 insertions, 18 deletions
@@ -1,7 +1,7 @@ Frequently Asked Questions (FAQ) for PostgreSQL - Last updated: Sun Oct 13 22:49:56 EDT 2002 + Last updated: Sun Oct 13 23:15:09 EDT 2002 Current maintainer: Bruce Momjian (pgman@candle.pha.pa.us) @@ -52,7 +52,7 @@ 3.6) How do I tune the database engine for better performance? 3.7) What debugging features are available? 3.8) Why do I get "Sorry, too many clients" when trying to connect? - 3.9) What are the pg_sorttempNNN.NN files in my database directory? + 3.9) What is in the pgsql_tmp directory? 3.10) Why do I need to do a dump and restore to upgrade PostgreSQL releases? @@ -197,8 +197,7 @@ distribution or the MS Windows FAQ at http://www.PostgreSQL.org/docs/faq-mswin.html. - A native port to some Microsoft platforms is currently being worked - upon. + A native port to MS Win NT/2000/XP is currently being worked on. 1.5) Where can I get PostgreSQL? @@ -368,7 +367,7 @@ 1.15) How can I financially assist PostgreSQL? PostgreSQL has had a first-class infrastructure since we started in - 1994. This is all thanks to Marc Fournier, who has created and managed + 1996. This is all thanks to Marc Fournier, who has created and managed this infrastructure over the years. Quality infrastructure is very important to an open-source project. It @@ -419,9 +418,9 @@ 2.3) Does PostgreSQL have a graphical user interface? A report generator? An embedded query language interface? - We have a nice graphical user interface called PgAccess, which is - shipped as part of the distribution. PgAccess also has a report - generator. The Web page is http://www.pgaccess.org/. + We have a nice graphical user interface called PgAccess which can also + be used as a report generator. The Web page is + http://www.pgaccess.org/. We also include ecpg, which is an embedded SQL query language interface for C. @@ -433,7 +432,7 @@ * C++ (libpq++) * Embedded C (ecpg) * Java (jdbc) - * Perl (DBD::Pg) + * Perl (DBD::Pg and perl5) * ODBC (odbc) * Python (PyGreSQL) * TCL (libpgtcl) @@ -441,7 +440,8 @@ * PHP ('pg_' functions, Pear::DB) Additional interfaces are available at - http://www.PostgreSQL.org/interfaces.html. + http://www.PostgreSQL.org/interfaces.html and + http://gborg.PostgreSQL.org. _________________________________________________________________ Administrative Questions @@ -596,16 +596,16 @@ was 64, and changing it required a rebuild after altering the MaxBackendId constant in include/storage/sinvaladt.h. - 3.9) What are the pg_tempNNN.NN files in my database directory? + 3.9) What are the pgsql_tmp directory? They are temporary files generated by the query executor. For example, if a sort needs to be done to satisfy an ORDER BY, and the sort requires more space than the backend's -S parameter allows, then temporary files are created to hold the extra data. - The temporary files should be deleted automatically, but might not if - a backend crashes during a sort. If you have no backends running at - the time, it is safe to delete the pg_tempNNN.NN files. + The temporary files are usually deleted automatically, but might + remain if a backend crashes during a sort. A stop and restart of the + postmaster will remove files from those directories. 3.10) Why do I need to do a dump and restore to upgrade between major PostgreSQL releases? @@ -649,8 +649,8 @@ 4.4) How do you remove a column from a table? - Prior to version 7.3, ALTER TABLE DROP COLUMN is not supported. You - can do this instead: + This functionality was added in release 7.3 with ALTER TABLE DROP + COLUMN. In earlier versions, you can do this: BEGIN; LOCK TABLE old_table; SELECT ... -- select all columns but the one you want to remove @@ -815,11 +815,11 @@ Case-insensitive equality comparisons are normally expressed as: SELECT * FROM tab - WHERE LOWER(col) = 'abc'; + WHERE lower(col) = 'abc'; This will not use an standard index. However, if you create a functional index, it will be used: - CREATE INDEX tabindex ON tab (LOWER(col)); + CREATE INDEX tabindex ON tab (lower(col)); 4.13) In a query, how do I detect if a field is NULL? |