nbtree: Remove useless 'strat' local variable.

petergeoghegan · petergeoghegan · commit b6558e4f837e · 2024-11-04T11:04:30.000-05:00
Remove a local variable that was used to avoid overwriting strat_total with the = operator strategy when a >= operator strategy key was already included in the initial positioning/insertion scan keys by _bt_first (for backwards scans it would have to be a <= key that was included). _bt_first's strat_total local variable now simply tracks the operator strategy of the final scan key that was included in the scan's insertion scan key (barring the case where the !used_all_subkeys row compare path adjusts strat_total in its own way). _bt_first already treated >= keys (or <= keys) as = keys for initial positioning purposes. There is no good reason to remember that that was what happened; no later _bt_first step cares about the distinction. Note, in particular, that the insertion scan key's 'nextkey' and 'backward' fields will be initialized the same way regardless. Author: Peter Geoghegan <pg@bowt.ie> Reviewed-By: Tomas Vondra <tomas@vondra.me> Discussion: https://postgr.es/m/CAH2-Wz=PKR6rB7qbx+Vnd7eqeB5VTcrW=iJvAsTsKbdG+kW_UA@mail.gmail.com
diff --git a/src/backend/access/nbtree/nbtsearch.c b/src/backend/access/nbtree/nbtsearch.c
@@ -883,7 +883,6 @@ _bt_first(IndexScanDesc scan, ScanDirection dir)
 	BTScanOpaque so = (BTScanOpaque) scan->opaque;
 	BTStack		stack;
 	OffsetNumber offnum;
-	StrategyNumber strat;
 	BTScanInsertData inskey;
 	ScanKey		startKeys[INDEX_MAX_KEYS];
 	ScanKeyData notnullkeys[INDEX_MAX_KEYS];
@@ -1090,18 +1089,11 @@ _bt_first(IndexScanDesc scan, ScanDirection dir)
 					break;
 				startKeys[keysz++] = chosen;
 
-				/*
-				 * Adjust strat_total, and quit if we have stored a > or <
-				 * key.
-				 */
-				strat = chosen->sk_strategy;
-				if (strat != BTEqualStrategyNumber)
-				{
-					strat_total = strat;
-					if (strat == BTGreaterStrategyNumber ||
-						strat == BTLessStrategyNumber)
-						break;
-				}
+				/* Quit if we have stored a > or < key */
+				strat_total = chosen->sk_strategy;
+				if (strat_total == BTGreaterStrategyNumber ||
+					strat_total == BTLessStrategyNumber)
+					break;
 
 				/*
 				 * Done if that was the last attribute, or if next key is not
