wangweiming800 commented on a change in pull request #741: PHOENIX-5791
Eliminate false invalid row detection due to concurrent …
URL: https://github.com/apache/phoenix/pull/741#discussion_r397521193
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File path:
phoenix-core/src/main/java/org/apache/phoenix/coprocessor/IndexRebuildRegionScanner.java
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@@ -614,38 +606,132 @@ private boolean isDeleteFamilyVersion(Mutation
mutation) {
return getMutationsWithSameTS(put, del);
}
+ private void repairActualMutationList(List<Mutation> actualMutationList,
List<Mutation> expectedMutationList)
+ throws IOException {
+ // find the first (latest) actual unverified put mutation
+ Mutation actual = null;
+ for (Mutation mutation : actualMutationList) {
+ if (mutation instanceof Put && !isVerified((Put) mutation)) {
+ actual = mutation;
+ break;
+ }
+ }
+ if (actual == null) {
+ return;
+ }
+ long ts = getTimestamp(actual);
+ int expectedIndex;
+ int expectedListSize = expectedMutationList.size();
+ for (expectedIndex = 0; expectedIndex < expectedListSize;
expectedIndex++) {
+ if (getTimestamp(expectedMutationList.get(expectedIndex)) <= ts) {
+ if (expectedIndex > 0) {
+ expectedIndex--;
+ }
+ break;
+ }
+ }
+ if (expectedIndex == expectedListSize) {
+ return;
+ }
+ for (; expectedIndex < expectedListSize; expectedIndex++) {
+ Mutation mutation = expectedMutationList.get(expectedIndex);
+ if (mutation instanceof Put) {
+ mutation = new Put((Put) mutation);
+ } else {
+ mutation = new Delete((Delete) mutation);
+ }
+ actualMutationList.add(mutation);
+ }
+ Collections.sort(actualMutationList, MUTATION_TS_DESC_COMPARATOR);
+ }
+
+ private void cleanUpActualMutationList(List<Mutation> actualMutationList)
+ throws IOException {
+ Iterator<Mutation> iterator = actualMutationList.iterator();
+ Mutation previous = null;
+ while (iterator.hasNext()) {
+ Mutation mutation = iterator.next();
+ if ((mutation instanceof Put && !isVerified((Put) mutation)) ||
+ (mutation instanceof Delete &&
isDeleteFamilyVersion(mutation))) {
+ iterator.remove();
+ } else {
+ if (previous != null && getTimestamp(previous) ==
getTimestamp(mutation) &&
+ ((previous instanceof Put && mutation instanceof Put)
||
+ previous instanceof Delete && mutation
instanceof Delete)) {
+ iterator.remove();
+ } else {
+ previous = mutation;
+ }
+ }
+ }
+ }
+
/**
- * indexRow is the set of all cells of all the row version of an index row
from the index table. These are actual
- * cells. We group these cells based on timestamp and type (put vs
delete), and form the actual set of
- * index mutations. indexKeyToMutationMap is a map from an index row key
to a set of mutations that are generated
- * using the rebuild process (i.e., by replaying raw data table
mutations). These sets are sets of expected
- * index mutations, one set for each index row key. Since not all
mutations in the index table have both phase
- * (i.e., pre and post data phase) mutations, we cannot compare actual
index mutations with expected one by one
- * and expect to find them identical. We need to consider concurrent data
mutation effects, data table row write
- * failures, post index write failures. Thus, we need to allow some
expected and actual mutations to be skipped
- * during comparing actual mutations to index mutations.
+ * There are two types of verification: without repair and with repair.
Without-repair verification is done before
+ * or after index rebuild. It is done before index rebuild to identify the
rows to be rebuilt. It is done after
+ * index rebuild to verify the rows that have been rebuilt. With-repair
verification can be done anytime using
+ * the “-v ONLY” option to check the consistency of the index table.
+ *
+ * Unverified Rows
+ *
+ * For each mutable data table mutation during regular data table updates,
two operations are done on the data table.
+ * One is to read the existing row state, and the second is to update the
data table for this row. The processing of
+ * concurrent data mutations are serialized once for reading the existing
row states, and then serialized again
+ * for updating the data table. In other words, they go through locking
twice, i.e., [lock, read, unlock] and
+ * [lock, write, unlock]. Because of this two phase locking, for a pair of
concurrent mutations (for the same row),
+ * the same row state can be read from the data table. This means the same
existing index row can be made unverified
+ * twice with different timestamps, one for each concurrent mutation.
These unverified mutations can be repaired
+ * from the data table later during HBase scans using the index read
repair process. This is one of the reasons
+ * for having extra unverified rows in the index table. The other reason
is the data table write failures.
+ * When a data table write fails, it leaves an unverified index row
behind. These rows are never returned to clients,
+ * instead they are repaired, which means either they are rebuilt from
their data table rows or they are deleted if
+ * their data table rows do not exist.
+ *
+ * Delete Family Version Markers
+ *
+ * The family version delete markers are generated by the read repair to
remove extra unverified rows. They only
Review comment:
delete marks is not only generated by the read repair. If there is a column
delete on the indexed column in data table, there will be family version delete
marker as well. Will it be a problem?
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