Обсуждение: BUG #17932: Cannot select big bytea values(>500MB)
The following bug has been logged on the website: Bug reference: 17932 Logged by: Hans Lee Email address: haduchiep@gmail.com PostgreSQL version: 13.10 Operating system: linux Description: Dear Support Team, I created a big bytea value and try to select it from a table, I get an error, something like: "ERROR: invalid memory alloc request size ...". it means i can insert data into table but then i can't even work with it. is it a bug? could you please help me to solve this Problem. Thank you very much for your support Best Regards Hiep
On Mon, May 15, 2023 at 5:21 PM PG Bug reporting form <noreply@postgresql.org> wrote:
> I created a big bytea value and try to select it from a table, I get
> an error, something like: "ERROR: invalid memory alloc request size
> ...".
> it means i can insert data into table but then i can't even work
> with it. is it a bug? could you please help me to solve this Problem.
> Thank you very much for your support
This is a known (but not documented as far as I know) issue, but it also depends on the data contents and how the value is retrieved. Possible workarounds:
1. If the data is largely printable ASCII, then try
setting "bytea_output" to "escape":
https://www.postgresql.org/docs/devel/runtime-config-client.html#GUC-BYTEA-OUTPUT
2. Request binary transmission in your application (if possible), for example "show_binary_results" in
https://www.postgresql.org/docs/devel/libpq-example.html
3. COPY out using binary format
> I created a big bytea value and try to select it from a table, I get
> an error, something like: "ERROR: invalid memory alloc request size
> ...".
> it means i can insert data into table but then i can't even work
> with it. is it a bug? could you please help me to solve this Problem.
> Thank you very much for your support
This is a known (but not documented as far as I know) issue, but it also depends on the data contents and how the value is retrieved. Possible workarounds:
1. If the data is largely printable ASCII, then try
setting "bytea_output" to "escape":
https://www.postgresql.org/docs/devel/runtime-config-client.html#GUC-BYTEA-OUTPUT
2. Request binary transmission in your application (if possible), for example "show_binary_results" in
https://www.postgresql.org/docs/devel/libpq-example.html
3. COPY out using binary format
Hello John Naylor,
Thank you very much for your support. After setting the "bytea_output" to "escape" and increasing the Java heap size of DBeaver (to 8GB), I can now see the big column (bytea > 500MB). I am still in the testing phase and haven't finished yet, but I wonder if clients with small RAM will be able to select these big columns or if bytea_output=escape will be visible in the application. Could you please explain this to me in more detail?
Thanks
Thank you very much for your support. After setting the "bytea_output" to "escape" and increasing the Java heap size of DBeaver (to 8GB), I can now see the big column (bytea > 500MB). I am still in the testing phase and haven't finished yet, but I wonder if clients with small RAM will be able to select these big columns or if bytea_output=escape will be visible in the application. Could you please explain this to me in more detail?
Thanks
Vào Th 3, 16 thg 5, 2023 vào lúc 08:58 John Naylor <john.naylor@enterprisedb.com> đã viết:
On Mon, May 15, 2023 at 5:21 PM PG Bug reporting form <noreply@postgresql.org> wrote:
> I created a big bytea value and try to select it from a table, I get
> an error, something like: "ERROR: invalid memory alloc request size
> ...".
> it means i can insert data into table but then i can't even work
> with it. is it a bug? could you please help me to solve this Problem.
> Thank you very much for your support
This is a known (but not documented as far as I know) issue, but it also depends on the data contents and how the value is retrieved. Possible workarounds:
1. If the data is largely printable ASCII, then try
setting "bytea_output" to "escape":
https://www.postgresql.org/docs/devel/runtime-config-client.html#GUC-BYTEA-OUTPUT
2. Request binary transmission in your application (if possible), for example "show_binary_results" in
https://www.postgresql.org/docs/devel/libpq-example.html
3. COPY out using binary format