Replace the sorted array of GUC variables with a hash table. This gets rid of bsearch() in favor of hashed lookup. The main advantage is that it becomes far cheaper to add new GUCs, since we needn't re-sort the pointer array. Adding N new GUCs had been O(N^2 log N), but now it's closer to O(N). We need to sort only in SHOW ALL and equivalent functions, which are hopefully not performance-critical to anybody.
Also, merge GetNumConfigOptions() into get_guc_variables(), because in a world where the set of GUCs isn't fairly static you really want to consider those two results as tied together not independent. Discussion: https://postgr.es/m/2982579.1662416...@sss.pgh.pa.us Branch ------ master Details ------- https://git.postgresql.org/pg/commitdiff/3057465acfbea2f3dd7a914a1478064022c6eecd Modified Files -------------- src/backend/utils/misc/guc.c | 385 ++++++++++++++++++++++------------- src/backend/utils/misc/guc_funcs.c | 39 ++-- src/backend/utils/misc/help_config.c | 5 +- src/include/utils/guc.h | 1 - src/include/utils/guc_tables.h | 2 +- 5 files changed, 272 insertions(+), 160 deletions(-)
