From: pgsql-hackers-ow...@postgresql.org [mailto:pgsql-hackers-ow...@postgresql.org] On Behalf Of Amit Kapila Sent: Monday, August 13, 2012 12:47 PM From: pgsql-hackers-ow...@postgresql.org [mailto:pgsql-hackers-ow...@postgresql.org] On Behalf Of Heikki Linnakangas Sent: Monday, August 13, 2012 12:14 PM On 12.08.2012 17:39, Tom Lane wrote: > Heikki Linnakangas<heikki.linnakan...@enterprisedb.com> writes:
>>> Hm, how did the same code fail to crash in the postmaster itself, when >>> the postmaster read the setting from postgresql.conf? >>It's not the check function for default_transaction_isolation that >>crashes, but the one for transaction_isolation. >> I 'm not exactly sure how transaction_isolation gets set to a non-default >> value, though. The default for transaction_isolation is 'default', so >> it's understandable that the underlying XactIsoLevel variable gets set >> to XACT_SERIALIZABLE, but AFAICS the code to read/write the GUCs from/to >> file only cares about the string value of the guc, not the integer value >> of the underlying global variable. > Here What I am able to trace is that function read_nondefault_variables(), > reads all variables > from config_exec_params which contains both default_transaction_isolation > and transaction_isolation. > 1. it first reads default_transaction_isolation and sets value of > DefaultXactIsoLevel to 'serializable'. > 2. As for parameter default_transaction_isolation, there is no check > function it passes. > 3. After that when variable transaction_isolation is processed, function > check_XactIsoLevel() sets > XactIsoLevel to XACT_SERIALIZABLE which causes crash. > Actually function read_nondefault_variables(), should only process non > default values (default_transaction_isolation) > not transaction_isolation, but currently it processes both? transaction_isolation is getting written to config_exec_params file as function write_one_nondefault_variable() checks if conf source is not PGC_S_DEFAULT, then it writes to file. For transaction_isolation, the conf source is set to PGC_S_OVERRIDE in function InitializeGUCOptions() so this also gets written to config_exec_params file. Should the parameter transaction_isolation be written to config_exec_params? With Regards, Amit Kapila. -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
