Ruizs Place

If you found this through a search, you probably have seen something like this in your logs:
ERROR: missing chunk number 0 for toast value 87246446

Searching for this issue on the net, I found that this is usually caused by a corrupt row in the database. The solution is to find the corrupt row, and delete it (and/or update it with proper, non-corrupt values).

Unfortunately, there is no easy way to find the row that is giving you grief (or even the table if you don’t know what is causing this error). You basically have to narrow down your search by looking at parts of the database. If you have some sort of date or timestamp column in your table, you can narrow it down a lot more easily, if you know approximately when the error started:


mydb=# select id from mytable where date_created > timestamp '2009-02-27 00:00:00' and date_created < timestamp '2009-03-01 23:59:00';
id
--------------------------------------
3ab226cf-a972-463d-b5a1-148fe39672b5
10daca73-b2b3-470c-a258-5c92d21cfbb6
(2 rows)


Luckily it's only two rows, and the first one is the culprit:

mydb=# select * from mytable where id='3ab226cf-a972-463d-b5a1-148fe39672b5';
ERROR: missing chunk number 0 for toast value 87246446


Now, on to delete it:
mydb=# delete from mytable where id='3ab226cf-a972-463d-b5a1-148fe39672b5';

If you don’t have a date/timestamp column in your table, you could use LIMIT and OFFSET to narrow it down. I.e. a series of statements like (increasing the offset each time):

select * from mytable order by id limit 1000 offset 5000;


I’ve been meaning to get around to it for the longest time, but I finally switched over my Mac’s to use bash as the default shell (previously I had it set to tcsh). I’ve become more accustomed to bash the past few years as its the default shell on pretty much any unix/linux nowadays, so it was time to migrate.

The migration itself was pretty easy, but I wanted to gain some of bash’s features, specifically the emac-like keystrokes for moving forward/back a word in the command line, and also to the beginning and end of the line. The keystrokes, among others, are:

ctrl-a Move cursor to beginning of line
ctrl-e Move cursor to end of line
meta-b Move cursor back one word
meta-f Move cursor forward one word
ctrl-w Cut the last word
ctrl-u Cut everything before the cursor
ctrl-k Cut everything after the cursor
ctrl-y Paste the last thing to be cut
ctrl-_ Undo


I’m a big fan of iTerm – I use it as my primary terminal and have been for the last few years, as it matured in terms of performance and has a lot of great features. The most compelling feature it has over the built in OSX Terminal.app, for me, is that you can specify which characters to include when selecting words. A common operation in a terminal is to select a path, i.e. /home/myuser/testfile. In Terminal.app, if you double click on home, it will just select home – so you have to go back, double click on the first “/” character, and mouse right to get the whole word. With iTerm, you can set a preference with characters to include when connecting, i.e. “/”, so when I double click on home in iTerm, it selects the full path. Specifically, in iTerm -> Preferences -> Mouse, i have “Characters considered part of word:” set to /-_.

One thing I couldn’t figure out was how to get the “meta” key in iterm set to the alt/option key on the mac keyboard. Turns out it’s buried in a non-intuitive place, but it can be done. In iTerm, go to Bookmarks->Manage Profiles, and under Keyboard Profiles select Global. On the right side, you need to set Option Key as “+Esc” for this to work – yes, its strange that it has to be Esc instead of Meta, but hey, at least it all works.