File size consideration of file_fdw in PostgreSQL

Started by Xiaobo Gualmost 13 years ago2 messagesgeneral
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#1Xiaobo Gu
guxiaobo1982@gmail.com

Hi,

We have very large files in size will be created as external tables in
PostgreSQL via file_fdw, we have the following considerations:
1. Can file_fdw handle files with size large than the size of RAM in the
server.
2. Will file_fdw scan the full file every time when the external table is
queried, even we have "where" clause to narrow to a subset of rows , as the
file_fdw doesn't have a server engine.

Can you help with this, thanks.

Xiaobo

#2Laurenz Albe
laurenz.albe@cybertec.at
In reply to: Xiaobo Gu (#1)
Re: File size consideration of file_fdw in PostgreSQL

Xiaobo Gu wrote:

We have very large files in size will be created as external tables in PostgreSQL via file_fdw, we
have the following considerations:
1. Can file_fdw handle files with size large than the size of RAM in the server.

That shouldn't be a problem.

2. Will file_fdw scan the full file every time when the external table is queried, even we have
"where" clause to narrow to a subset of rows , as the file_fdw doesn't have a server engine.

Yes, the complete file will be read whenever the foreign
table is queried.

Yours,
Laurenz Albe

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