Improve comment in hashsearch.c.

Typo fix from Mithun Cy; other improvements by me.

diff --git a/src/backend/access/hash/hashsearch.c b/src/backend/access/hash/hashsearch.c
index c0bdfe6f1fb3be61f6c137e5da8dcd7291c76b03..a59ad6ff7079f2af0e491ceff37849e99fc79c91 100644 (file)
--- a/src/backend/access/hash/hashsearch.c
+++ b/src/backend/access/hash/hashsearch.c
@@ -334,19 +334,20 @@ _hash_first(IndexScanDesc scan, ScanDirection dir)
    so->hashso_bucket_buf = buf;
 
    /*
-    * If the bucket split is in progress, then while scanning the bucket
-    * being populated, we need to skip tuples that are moved from bucket
-    * being split.  We need to maintain the pin on bucket being split to
+    * If a bucket split is in progress, then while scanning the bucket being
+    * populated, we need to skip tuples that were copied from bucket being
+    * split.  We also need to maintain a pin on the bucket being split to
     * ensure that split-cleanup work done by vacuum doesn't remove tuples
-    * from it till this scan is done.  We need to main to maintain the pin on
+    * from it till this scan is done.  We need to maintain a pin on the
     * bucket being populated to ensure that vacuum doesn't squeeze that
-    * bucket till this scan is complete, otherwise the ordering of tuples
+    * bucket till this scan is complete; otherwise, the ordering of tuples
     * can't be maintained during forward and backward scans.  Here, we have
-    * to be cautious about locking order, first acquire the lock on bucket
-    * being split, release the lock on it, but not pin, then acquire the lock
-    * on bucket being populated and again re-verify whether the bucket split
-    * still is in progress.  First acquiring lock on bucket being split
-    * ensures that the vacuum waits for this scan to finish.
+    * to be cautious about locking order: first, acquire the lock on bucket
+    * being split; then, release the lock on it but not the pin; then,
+    * acquire a lock on bucket being populated and again re-verify whether
+    * the bucket split is still in progress.  Acquiring the lock on bucket
+    * being split first ensures that the vacuum waits for this scan to
+    * finish.
     */
    if (H_BUCKET_BEING_POPULATED(opaque))
    {