Hello,
I want to store image data into sqlite by spliting image to many
blocks(256*256pixels). In my table, each row contain one block and some
other information, about 4~7column totally. The table has the 32K page size,
and I make these pragma: journal_mode = OFF, synchronous = OFF, locking_mode
= EXCLUSIVE, temp_store = MEMORY, compiling sqlite3 with no thread safety.
I have a image file about 400M, in tiff format. I import it inot sqlite
database, get a table with 9000 row( every row contain a 64K blob). If I
read all image data by SELECT statment:
SELECT ROWNUM, COLNUM, GEOR FROM RDT_1 (GEOR is the image blob
column)
it would tabke almost 18 seconds to read all image blob. Almost all time is
consumed by sqlite3_step(). But If I read tif file directly by GDAL, it only
take 8 seconds to get all data.
Is there any strategy I can followed to improve the blob read? Accessing any
blob in sqlite is very quickly, but now I have to read all blob in a large
table, so how can I read as quickly as possible?
Thank you for any suggestion and discuss! And if there is a sloution in some
where, please give me a url. Thanks!
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