Re[2]: [patches] Re: [PATCH] Fix force_recovery on empty xlog

[Konstantin Belyavskiy]

>
>> 
>>  /*
>>   * Recovery subsystem
>> @@ -330,20 +332,26 @@ recovery_finalize(struct recovery *r, struct xstream *stream)
>>  	recovery_close_log(r);
>> 
>>  	/*
>> -	 * Check that the last xlog file has rows.
>> +	 * Rename last corrupted xlog if any. Cases:
>> +	 *  - file has corrupted rows
>> +	 *  - file has corrupted header
>> +	 *  - file has zero size
>>  	 */
>> -	if (vclockset_last(&r->wal_dir.index) != NULL &&
>> -	    vclock_sum(&r->vclock) ==
>> -	    vclock_sum(vclockset_last(&r->wal_dir.index))) {
>> -		/*
>> -		 * Delete the last empty xlog file.
>> -		 */
>> +	if (vclockset_last(&r->wal_dir.index) != NULL) {
>>  		char *name = xdir_format_filename(&r->wal_dir,
>>  						  vclock_sum(&r->vclock),
>>  						  NONE);
>> -		if (unlink(name) != 0) {
>> -			tnt_raise(SystemError, "%s: failed to unlink file",
>> -				  name);
>> +		if (access(name, F_OK) == 0 ||
>
>> +		    vclock_sum(&r->vclock) ==
>> +		    vclock_sum(vclockset_last(&r->wal_dir.index))) {
>
>If there's an xlog file corresponding to r->vclock in r->wal_dir.index,
>it must exist, i.e. access() must return 0 for it. That said, the second
>check looks redundant.
>
>Come to think of it, we have scanned the whole xlog directory in
>xdir_scan() by the time we get here so using access() here looks
>strange. Can we call rename() right from xdir_scan() for files that
>we failed to index (corrupted header, empty)?
>
If xlog has corrupted data but header is OK, when second check
vclock_sum(&r->vclock) == vclock_sum(vclockset_last(&r->wal_dir.index))

But should we rename on xdir_scan() ? Good question BTW..
Roman, Konstantin, what do you think?


С уважением,
Konstantin Belyavskiy
k.belyavskiy at tarantool.org
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