Re: Speeding up the Postgres lexer
| От | Andrew Dunstan |
|---|---|
| Тема | Re: Speeding up the Postgres lexer |
| Дата | |
| Msg-id | 42923E6E.3080906@dunslane.net обсуждение исходный текст |
| Ответ на | Speeding up the Postgres lexer (Tom Lane <tgl@sss.pgh.pa.us>) |
| Ответы |
Re: Speeding up the Postgres lexer
|
| Список | pgsql-hackers |
Tom Lane wrote:
>[snip - flex is slowed down by backtracking - how to fix ]
>
>What I'm wondering is whether this is really worth doing or not.
>There are currently just two parts of the lexer rules that are affected
>--- the {real} rule illustrated above, and the rules that allow quoted
>strings to be split across lines as the SQL spec requires. But the
>patches are still pretty ugly, and what's really annoying is that there
>doesn't seem to be any way to get flex to complain if someone later
>makes a change that breaks the no-backup-cases property again.
>
>
>
I would be more concerned if there were not reasonable alternatives to
many bulk parsed inserts (COPY, prepared statement).
But I do think it's worth it, even so ... not all client interfaces
support prepared statements (notoriously PHP, although I understand KL
has sent patches to fix that) and not all inserts are suitable for COPY.
cheers
andrew
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