blob field with compression data is not valid

Blob field with compression data is not valid how to#
Blob field with compression data is not valid zip file#

Exposes a Connection string field for this purpose. Manual: Use this default option to enter your Azure Storage connection string directly. Use the Authentication method buttons to select one of these options: Selecting Parquet (supported only on Linux, not Windows) exposes a Parquet Settings left tab, where you must configure certain options in order to export data in Parquet format. (This field is not displayed or available on Cribl.Cloud-managed Worker Nodes.)ĭata format: The output data format defaults to JSON. Cribl recommends that this location be stable and high-performance.

Staging location: Local filesystem location in which to buffer files before compressing and moving them to the final destination. This restriction is imposed by Azure.īlob prefix: Root directory to prepend to path before uploading. * blob the target BLOB (will hold compressed binary data) it should be an empty BLOB retrieved for example with dbms_lob.Container names can include only lowercase letters, numbers, and/or hyphens ( -). * slob the source BLOB (plain binary data) * A simple class for LOB compression and decompression in Oracle Database. This bug it officially fixed in 11gR2.Ĭreate or replace and compile java source named “LobCompressor” as UTL_COMPRESS has very bad compression ratio sometimes. I had to use it because I spotted Oracle bug 7337717, 3861722.

Blob field with compression data is not valid how to#

There are other ways how to compress a blob. ** Added more support for non-ascii filenames ** Central file header instead of Local file header ** Take CRC32, compressed length and uncompressed length from

** fixed bug for large uncompressed files, thanks Morten Braten ** added support for defate64 (this only works for zip-files created with 7Zip)

Blob field with compression data is not valid zip file#

** fixed endless loop for empty/null zip file Utl_compress.lz_uncompress_close( t_hdl ) T_last_chr := to_number( dbms_lob.substr( p_src, 2, dbms_lob.getlength( p_src ) - 1 ), '0XXX')ĭbms_lob.append( t_out, hextoraw( to_char( t_last_chr, 'fm0X' ) ) ) Utl_compress.lz_uncompress_extract( t_hdl, t_buffer ) T_hdl := utl_compress.lz_uncompress_open( t_tmp ) T_s1 pls_integer - s1 part of adler32 checksumĭbms_lob.createtemporary( t_out, false ) ĭbms_lob.createtemporary( t_tmp, false ) But the value of this last byte can derived from the Adler32 checksum we have!įunction zlib_decompress( p_src in blob ) If we try to get the last decompressed byte an exception ORA-29294: A data error occurred during compression or uncompression, is raised. But only until the last byte of the uncompressed data. And that works without the correct trailer. But utl_compress has another procedure lz_uncompress_extract, which can be used to decompress the input byte for byte. And that’s something we don’t have and can’t calculate with the data we have. Utl_compress.lz_decompress only works if the input has a correct trailer, which includes a crc32-checksum of the uncompressed data. Unwrapping the zlib-format with utl_compress takes just a little more effort. T_cpr := hextoraw( '789C' ) - zlib headerĭbms_lob.copy( t_cpr, t_tmp, dbms_lob.getlength( t_tmp ) - 10 - 8, 3, 11 ) ĭbms_lob.append( t_cpr, hextoraw( adler32( p_src ) ) ) - zlib trailer

T_tmp := utl_compress.lz_compress( p_src ) ĭbms_lob.createtemporary( t_cpr, false ) With this Adler32 function compressing it zlib-format is nothing more as a simple wrapper for utl_compress.lz_compress Return to_char( s2, 'fm0XXX' ) || to_char( s1, 'fm0XXX' ) Yes! In fact all you need is how to calculate the Adler32-checksum, which is used as the trailer of the zlib-format.įor i in 1. So can utl_compress be used to for compressing/decompressing data according to the zlib-specs. Both formats use the same algorithm, RFC 1951, but have different headers and trailers. And that may be very useful (but I have never used it), but I need compression (I’m working on a PDF-generator in PL/SQL) and decompression (unwrapping wrapped PL/SQL!) in the zlib-format, RFC 1950. That means it’s following the RFC 1952 specs, RFC 1952. According to the documentation it uses the “Lempel-Ziv compression algorithme”, and “The output of the UTL_COMPRESS compressed data is compatible with gzip”.

Oracle has a a supplied package utl_compress, which can be used to compress and decompress data with PL/SQL.