>>> Based on the discussion and suggestions in this mail chain, following features can be implemented: >>> >>> 1. To compute the value of max LSN in data pages based on user input whether he wants it for an individual
>>> file, a particular directory or whole database. >> >>> 2a. To search the available WAL files for the latest checkpoint record and prints the value. >>> 2b. To search the available WAL files for the latest checkpoint record and recreates a pg_control file pointing at
>>> that checkpoint.
>>> I have kept both options to address different kind of corruption scenarios.
>> I think I can see all of those things being potentially useful. There >> are a couple of pending patches that will revise the WAL format >> slightly; not sure how much those are likely to interfere with any >> development you might do on (2) in the meantime.
> Based on above conclusion, I have prepared a patch which implements Option-1
This mail contains doc patch Option-1 and test cases.
Below are test scenarios corresponding to which testcases are in Test_find_max_lsn_from_datafiles
Scenario-1: Validation of the maximum LSN number & in data base directory Steps: 1. Start the server, create table, insert some records into the table. 2. Shutdown the server in normal mode. 3. ./pg_resetxlog -P data to find the maximum LSN number and validate with the current pg_xlog directory and in pg_control file Expected behavior: Displayed maximum LSN number should to same as in pg_control file & WAL segment number displayed (fileid, segnum) should be same current file in pg_xlog directory.
Scenario-2: Validation of the maximum LSN number & in specific directory Steps: 1. Start the server, create table, insert some records into the table. 2. Shutdown the server in normal mode. 3. ./pg_resetxlog -p base/1/12557/ data Expected behavior: Displayed maximum LSN number should to same as in pg_control file & WAL segment number displayed (fileid, segnum) should be same current file in pg_xlog directory.
Scenario-3: Validation of the maximum LSN number & in specific file Steps: 1. Start the server, create table, insert some records into the table. 2. Shutdown the server in normal mode. 3. ./pg_resetxlog -p base/1/12557/16384 data Expected behavior: Displayed maximum LSN number should to same as in pg_control file & WAL segment number displayed (fileid, segnum) should be same current file in pg_xlog directory.
