Thread: Warning during pg_dump
Hi everyone, when i issued the following command: pg_dump -d mydb -Fc -Z9 -U dbadmin > base_backup.tar i keep getting warning messages: pg_dump: [custom archiver] WARNING: ftell mismatch with expected position -- ftell used. Do i have to be worried about that, i.e. can it happen that the backup did not work? Mainly because my db is around 100GBand the tar file was just 4.5GB. I mean, i don't mind such a good compression but with the warning messages i got, iam a little bit confused as to whether it really worked. Thanks! Chris Christian Rengstl M.A. Klinik und Poliklinik für Innere Medizin II Kardiologie - Forschung Universitätsklinikum Regensburg B3 1.388 Franz-Josef-Strauss-Allee 11 93053 Regensburg Tel.: +49-941-944-7230
"Christian Rengstl" <Christian.Rengstl@klinik.uni-regensburg.de> writes: > when i issued the following command: pg_dump -d mydb -Fc -Z9 -U dbadmin > base_backup.tar > i keep getting warning messages: pg_dump: [custom archiver] WARNING: ftell mismatch with expected position -- ftell used. This is definitely not very cool. What platform are you on exactly (particularly, libc or glibc version), and what PG version is this? Can you make up a self-contained test case --- perhaps a script that fills a database with junk data that will produce the problem when dumped? regards, tom lane
Hi all, I have a small coding problem where my function is becoming, well, too ugly for comfort. I haven't finished it but you will get picture below. First a small description of the purpose. I have an aggregate function that takes a string and simply concatenates that string to the previous (internal state) value of the aggregate, example: "Hello:World" || ", " || "World:Hello" --> "Hello:World, World:Hello" My problem is that I sometimes get the same value before the colon sign and in those cases I should not add the whole string to the previous value of the aggregate but extract the value that is behind the colon and add it to already existing part which matched the value before the colon but with a slash as a delimiter, example: Internal state: "Hello:World, World:Hello" New value: "Hello:Dolly" After function is run: "Hello:World/Dolly, World:Hello" So what I am doing is a lot of strpos() and substr() functions (I have previously asked for the speed of the substr() function) but it is beginning to look really alwful. It seems very odd that there doesn't exist something else like what I need but I haven't found anything, although I admit I might not understand all aspects of the PostGreSQL database and what I can do with the SQL in connection to it. Below you will find my unfinished function, but it will show you what I mean when I say ugly.. Any help is appreciated. Thanks in advance, Archie CREATE FUNCTION rarity_concat(text, text) RETURNS text AS 'DECLARE colon_pos integer; set_str text; rarity_str text; set_exist_pos integer; rarity_exist_str_middle text; rarity_exist_str_end text; BEGIN colon_pos := strpos($2, ':'); set_str := substr($2, 1, colon_pos); set_exist_pos := strpos($1, set_str); IF set_exist_pos > 0 THEN rarity_str := substr($2, colon_pos + 2); rarity_exist_str_start := substr($1, 1, set_exist_pos - 1); comma_pos := ELSE RETURN $1 || \', \' || $2; END IF; END' LANGUAGE 'plpgsql';
Well, first off, this would be much easier in one of the other pl's such as for perl or ruby. Using plpgsql, I would suggest using more of the string function split_part since you know the delimiters the string can split on, using str_pos just to verify that there is say a '/' in a part of the string. Or, you could use the substring function (regex) to pull out portions to process (this is where plperl and plruby would work much better). Then just loop through, continually splitting the string down into it's component parts, maybe placing the component parts into arrays to preserve the relationships, then do your checks for equality against the "keys" that you've split up and rebuild the whole string from the ground up. arsi@aranzo.netg.se wrote: > > Hi all, > > I have a small coding problem where my function is becoming, well, too > ugly for comfort. I haven't finished it but you will get picture below. > > First a small description of the purpose. I have an aggregate function > that takes a string and simply concatenates that string to the > previous (internal state) value of the aggregate, example: > > "Hello:World" || ", " || "World:Hello" --> "Hello:World, World:Hello" > > My problem is that I sometimes get the same value before the colon > sign and in those cases I should not add the whole string to the > previous value of the aggregate but extract the value that is behind > the colon and add it to already existing part which matched the value > before the colon but with a slash as a delimiter, example: > > Internal state: "Hello:World, World:Hello" New value: "Hello:Dolly" > After function is run: "Hello:World/Dolly, World:Hello" > > So what I am doing is a lot of strpos() and substr() functions (I have > previously asked for the speed of the substr() function) but it is > beginning to look really alwful. > > It seems very odd that there doesn't exist something else like what I > need but I haven't found anything, although I admit I might not > understand all aspects of the PostGreSQL database and what I can do > with the SQL in connection to it. > > Below you will find my unfinished function, but it will show you what > I mean when I say ugly.. > > Any help is appreciated. > > Thanks in advance, > > Archie > > > CREATE FUNCTION rarity_concat(text, text) > RETURNS text > AS > 'DECLARE > colon_pos integer; > set_str text; > rarity_str text; > set_exist_pos integer; > rarity_exist_str_middle text; > rarity_exist_str_end text; > BEGIN > colon_pos := strpos($2, ':'); > set_str := substr($2, 1, colon_pos); > set_exist_pos := strpos($1, set_str); > IF set_exist_pos > 0 THEN > rarity_str := substr($2, colon_pos + 2); > rarity_exist_str_start := substr($1, 1, set_exist_pos - 1); > comma_pos := > ELSE > RETURN $1 || \', \' || $2; > END IF; > END' > LANGUAGE 'plpgsql'; > > ---------------------------(end of broadcast)--------------------------- > TIP 9: In versions below 8.0, the planner will ignore your desire to > choose an index scan if your joining column's datatypes do not > match -- erik jones <erik@myemma.com> software development emma(r)
On 2006-10-03, arsi@aranzo.netg.se <arsi@aranzo.netg.se> wrote: > Hi all, > > I have a small coding problem where my function is becoming, well, too > ugly for comfort. I haven't finished it but you will get picture below. > > First a small description of the purpose. I have an aggregate function > that takes a string and simply concatenates that string to the previous > (internal state) value of the aggregate, example: > > "Hello:World" || ", " || "World:Hello" --> "Hello:World, World:Hello" > > My problem is that I sometimes get the same value before the colon > sign and in those cases I should not add the whole string to the previous > value of the aggregate but extract the value that is behind the colon and > add it to already existing part which matched the value before the colon > but with a slash as a delimiter, example: > > Internal state: "Hello:World, World:Hello" > New value: "Hello:Dolly" > After function is run: "Hello:World/Dolly, World:Hello" > > So what I am doing is a lot of strpos() and substr() functions (I have > previously asked for the speed of the substr() function) but it is > beginning to look really alwful. You might have better luck with a different approach. For example, start by accumulating the values into an array, rather than a string, and rather than try and do the magic bits in the transition function, do them in one pass at the end, making use of the full power of SQL queries rather than trying to do your own procedural logic. If you think about your problem in SQL terms, what you're really trying to do is essentially a "group by" on your first field. If you can avoid the need to pass that in as a colon-delimited value, then your life will be much simpler; but even if you can't avoid that, the SQLish solution will be easier. As a sample of what you can do, here is a function that does part of the job (requires the array_accum aggregate as given as an example in the manual): create function foo(text[]) returns text[] language sql immutable as $f$ select ARRAY(select k || ':' || array_to_string(v,'/') from (select split_part($1[i],':',1) as k, array_accum(substring($1[i] from ':(.*)')) as v from generate_series(array_lower($1,1), array_upper($1,1)) s(i) group by k) s1) $f$; => select array_to_string(foo(ARRAY['foo:bar', 'baz:quux', 'foo:baz']),','); array_to_string ---------------------- baz:quux,foo:bar/baz (1 row) To understand the function, look at the subqueries from the inside out; the inner one splits the foo:bar elements into two columns, groups by the first and collects the corresponding values into an array; the outer one converts the format back to the one you require. As a bonus, if you want to eliminate duplicate values, you can just add the "distinct" keyword inside the array_accum aggregate. -- Andrew, Supernews http://www.supernews.com - individual and corporate NNTP services
Hello Archie, We approach the problem slightly differently then others. Given an aggregate function comma_list which simply creates a comma seperated list, we use distinct to remove duplicates. test=# select comma_list(col) from test; comma_list ------------ a, b, a, c (1 row) test=# select comma_list(distinct col) from test; comma_list ------------ a, b, c (1 row) I've included our function definitions below. hope that helps, -Chris CREATE OR REPLACE FUNCTION list_add(text, text) RETURNS text AS $BODY$ select CASE WHEN $2 IS NULL OR $2 ='' THEN $1 WHEN $1 IS NULL or $1 = '' THEN $2 ELSE $1 || ', ' || $2 END; $BODY$ LANGUAGE 'sql' VOLATILE; CREATE OR REPLACE FUNCTION list_fin(text) RETURNS text AS $BODY$ SELECT CASE WHEN $1=text('') THEN NULL ELSE $1 END $BODY$ LANGUAGE 'sql' VOLATILE; CREATE AGGREGATE comma_list( BASETYPE=text, SFUNC=list_add, STYPE=text, FINALFUNC=list_fin ); On Tuesday 03 October 2006 03:26 pm, arsi@aranzo.netg.se wrote: > Hi all, > > I have a small coding problem where my function is becoming, well, too > ugly for comfort. I haven't finished it but you will get picture below. > > First a small description of the purpose. I have an aggregate function > that takes a string and simply concatenates that string to the previous > (internal state) value of the aggregate, example: > > "Hello:World" || ", " || "World:Hello" --> "Hello:World, World:Hello" > > My problem is that I sometimes get the same value before the colon > sign and in those cases I should not add the whole string to the previous > value of the aggregate but extract the value that is behind the colon and > add it to already existing part which matched the value before the colon > but with a slash as a delimiter, example: > > Internal state: "Hello:World, World:Hello" > New value: "Hello:Dolly" > After function is run: "Hello:World/Dolly, World:Hello" > > So what I am doing is a lot of strpos() and substr() functions (I have > previously asked for the speed of the substr() function) but it is > beginning to look really alwful. > > It seems very odd that there doesn't exist something else like what I need > but I haven't found anything, although I admit I might not understand all > aspects of the PostGreSQL database and what I can do with the SQL in > connection to it. > > Below you will find my unfinished function, but it will show you what I > mean when I say ugly.. > > Any help is appreciated. > > Thanks in advance, > > Archie > > > CREATE FUNCTION rarity_concat(text, text) > RETURNS text > AS > 'DECLARE > colon_pos integer; > set_str text; > rarity_str text; > set_exist_pos integer; > rarity_exist_str_middle text; > rarity_exist_str_end text; > BEGIN > colon_pos := strpos($2, ':'); > set_str := substr($2, 1, colon_pos); > set_exist_pos := strpos($1, set_str); > IF set_exist_pos > 0 THEN > rarity_str := substr($2, colon_pos + 2); > rarity_exist_str_start := substr($1, 1, set_exist_pos - 1); > comma_pos := > ELSE > RETURN $1 || \', \' || $2; > END IF; > END' > LANGUAGE 'plpgsql'; > > ---------------------------(end of broadcast)--------------------------- > TIP 9: In versions below 8.0, the planner will ignore your desire to > choose an index scan if your joining column's datatypes do not > match -- Chris Kratz