ackelcn created DERBY-7082:
------------------------------
Summary: A rotten comment in IndexStatisticsDaemonImpl.java
Key: DERBY-7082
URL: https://issues.apache.org/jira/browse/DERBY-7082
Project: Derby
Issue Type: Bug
Reporter: ackelcn
When I read the code of DataDictionaryImpl.java, I found a comment:
{code:java}
private void setHeapRowEstimate(TransactionController tc, long tableId,
long rowEstimate)
throws StandardException {
// DERBY-4116: If we know the row count, update the store estimated row
// count for the table.
ScanController sc = tc.openScan(
...
}{code}
The comment mentions DERBY-4116. I found that DERBY-4116 modified
AlterTableConstantAction.java, and the patch is as follows:
{code:java}
@@ -779,6 +782,33 @@@@ -779,6 +782,33 @@
} // for each leading column (c1) (c1,c2)....
} // for each index.
++ // DERBY-4116 if there were indexes we scanned, we now know the row count.
+ // Update statistics should update the store estimated row count for the
table.
+ // If we didn't scan an index and don't know, numRows will still be -1 and
+ // we skip the estimatedRowCount update.
+
+ if (numRows == -1)
+ return;
+
+ ScanController heapSC = tc.openScan(td.getHeapConglomerateId(),
+ false, // hold
+ 0, // openMode: for read
+ TransactionController.MODE_RECORD, // locking
+ TransactionController.ISOLATION_READ_UNCOMMITTED, //isolation level
+ null, // scancolumnlist-- want everything.
+ null, // startkeyvalue-- start from the beginning.+ 0,
+ null, // qualifiers, none!
+ null, // stopkeyvalue,+ 0);
+
+ try {
+ heapSC.setEstimatedRowCount(numRows);
+ } finally {
+ heapSC.close();
+ }
+ }
{code}
The patch modified the updateStatistics method. However, the method is totaly
rewritten by follow-up commits, and the method does not contain the above added
lines any more.
I am wondering whether IndexStatisticsDaemonImpl.java mentions a rotten issue
report (DERBY-4116--), in that all the modifications of this issue do not
appear in the latest version.
Would you please check the problem? If it is, the reference of DERBY-4116 shall
be removed from the comment of DataDictionaryImpl.java.
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