On Thu, Mar 5, 2015 at 9:14 PM, Syed, Rahila <rahila.s...@nttdata.com> wrote: > Please find attached a patch. As discussed, flag to denote compression and > presence of hole in block image has been added in XLogRecordImageHeader > rather than block header. > > Following are WAL numbers based on attached test script posted by Michael > earlier in the thread. > > WAL generated > FPW compression on 122.032 MB > > FPW compression off 155.223 MB > > HEAD 155.236 MB > > Compression : 21 % > Number of block images generated in WAL : 63637
ISTM that we are getting a nice thing here. I tested the patch and WAL replay is working correctly. Some nitpicky comments... + * bkp_info stores flags for information about the backup block image + * BKPIMAGE_IS_COMPRESSED is used to identify if a given block image is compressed. + * BKPIMAGE_WITH_HOLE is used to identify the presence of a hole in a block image. + * If the block image has no hole, it is ensured that the raw size of a compressed + * block image is equal to BLCKSZ, hence the contents of + * XLogRecordBlockImageCompressionInfo are not necessary. Take care of the limit of 80 characters per line. (Perhaps you could run pgindent on your code before sending a patch?). The first line of this paragraph is a sentence in itself, no? In xlogreader.c, blk->with_hole is a boolean, you could remove the ==0 and ==1 it is compared with. + /* + * Length of a block image must be less than BLCKSZ + * if the block has hole + */ "if the block has a hole." (End of the sentence needs a dot.) + /* + * Length of a block image must be equal to BLCKSZ + * if the block does not have hole + */ "if the block does not have a hole." Regards, -- Michael -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
