Hi,

I think it's rather uncommon to use a query for a computed column. What is
your use case? What does the query look like exactly?

I don't know what the problem could be. The most obvious things is to
ensure the query is fast, but I guess you have already verified that,
right? Then, I would probably use the built-in profiler or just "jps -l"
and "jstack -l <pid>" to get a few full thread dumps. That way you can find
out what exactly is slow.

Regards,

Thomas

On Thursday, April 12, 2012, JND wrote:

Hi,

Wondering if this rings a bell with anyone. I have some tables with a few
million rows each. It's all speedy enough unless I have a computed column
(for example VARCHAR(5) AS (SELECT ... FROM indexed_relation...). To begin
with, if I add an extra million rows to a table that has no computed
column, the operation only takes a few seconds. If I then add a computed
column to that table, for example a computed column that selects on a
related table (using PK), the 'alter table' takes a few seconds. So there
is no problem with the computed select column per se. But then, if I insert
another million rows, the operation takes hours (if it ever finishes at
all...). So inserting rows when there is an existing computed select column
is unusably problematic. Just thought someone else might have definitely or
definitely NOT experienced this same issue. It's consistent for H2 1.2 as
well as 1.3. (I'll try to file a test case and bug report in the next few
days, but have to get other things done to meet a deadline, having lost a
whole afternoon and most of today to tracing this issue.)

James

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