[Backport 2.x] Transform maxclauses fix (#477) (#487)

* Transform maxclauses fix (#477)

* transform maxClauses fix

Signed-off-by: Petar Dzepina <petar.dzepina@gmail.com>

* added bucket log to track processed buckets

Signed-off-by: Petar Dzepina <petar.dzepina@gmail.com>

* various renames/changes

Signed-off-by: Petar Dzepina <petar.dzepina@gmail.com>

* fixed detekt issues

Signed-off-by: Petar Dzepina <petar.dzepina@gmail.com>

* added comments to test

Signed-off-by: Petar Dzepina <petar.dzepina@gmail.com>

* removed debug logging

Signed-off-by: Petar Dzepina <petar.dzepina@gmail.com>

* empty commit to trigger checks

Signed-off-by: Petar Dzepina <petar.dzepina@gmail.com>

* reduced pageSize to 1 in few ITs to avoid flaky tests; fixed bug where pagesProcessed was calculated incorrectly

Signed-off-by: Petar Dzepina <petar.dzepina@gmail.com>

* reverted pagesProcessed change; fixed few ITs

Signed-off-by: Petar Dzepina <petar.dzepina@gmail.com>

Signed-off-by: Petar Dzepina <petar.dzepina@gmail.com>
(cherry picked from commit 7475cfd)

* Update TransformRunnerIT.kt

Co-authored-by: Petar Dzepina <petar.dzepina@gmail.com>

src/main/kotlin/org/opensearch/indexmanagement/transform/TransformProcessedBucketLog.kt

@@ -0,0 +1,49 @@
+/*
+ * Copyright OpenSearch Contributors
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+package org.opensearch.indexmanagement.transform
+
+import java.math.BigInteger
+import java.security.MessageDigest
+
+class TransformProcessedBucketLog {
+
+    companion object {
+        const val MAX_SIZE = 100_000_000
+        const val HEX_RADIX = 16
+    }
+
+    private var processedBuckets: MutableSet<String> = HashSet()
+
+    fun addBuckets(buckets: List<Map<String, Any>>) {
+        buckets.forEach {
+            addBucket(it)
+        }
+    }
+
+    fun addBucket(bucket: Map<String, Any>) {
+        if (processedBuckets.size >= MAX_SIZE) return
+        processedBuckets.add(computeBucketHash(bucket))
+    }
+
+    fun isProcessed(bucket: Map<String, Any>): Boolean {
+        return processedBuckets.contains(computeBucketHash(bucket))
+    }
+
+    fun isNotProcessed(bucket: Map<String, Any>) = !isProcessed(bucket)
+
+    fun computeBucketHash(bucket: Map<String, Any>): String {
+        val md5Crypt = MessageDigest.getInstance("MD5")
+        bucket.entries.sortedBy { it.key }.also {
+            it.forEach { entry ->
+                md5Crypt.update(
+                    if (entry.value == null) "null".toByteArray()
+                    else entry.value.toString().toByteArray()
+                )
+            }
+        }
+        return BigInteger(1, md5Crypt.digest()).toString(HEX_RADIX)
+    }
+}

src/main/kotlin/org/opensearch/indexmanagement/transform/TransformRunner.kt

@@ -112,8 +112,7 @@ object TransformRunner :
             TimeValue.timeValueMillis(TransformSettings.DEFAULT_RENEW_LOCK_RETRY_DELAY),
             TransformSettings.DEFAULT_RENEW_LOCK_RETRY_COUNT
         )
-
-        var attemptedToIndex = false
+        val transformProcessedBucketLog = TransformProcessedBucketLog()
         var bucketsToTransform = BucketsToTransform(HashSet(), metadata)
         var lock = acquireLockForScheduledJob(transform, context, backoffPolicy)
         try {
@@ -134,7 +133,7 @@ object TransformRunner :
                             currentMetadata = validatedMetadata
                             return
                         }
-                        if (transform.continuous && (bucketsToTransform.shardsToSearch == null || bucketsToTransform.currentShard != null)) {
+                        if (transform.continuous) {
                             // If we have not populated the list of shards to search, do so now
                             if (bucketsToTransform.shardsToSearch == null) {
                                 // Note the timestamp when we got the shard global checkpoints to the user may know what data is included
@@ -145,11 +144,29 @@ object TransformRunner :
                                     newGlobalCheckpoints
                                 )
                             }
-                            bucketsToTransform = getBucketsToTransformIteration(transform, bucketsToTransform)
-                            currentMetadata = bucketsToTransform.metadata
+                            // If there are shards to search do it here
+                            if (bucketsToTransform.currentShard != null) {
+                                // Computes aggregation on modified documents for current shard to get modified buckets
+                                bucketsToTransform = getBucketsToTransformIteration(transform, bucketsToTransform).also {
+                                    currentMetadata = it.metadata
+                                }
+                                // Filter out already processed buckets
+                                val modifiedBuckets = bucketsToTransform.modifiedBuckets.filter {
+                                    transformProcessedBucketLog.isNotProcessed(it)
+                                }.toMutableSet()
+                                // Recompute modified buckets and update them in targetIndex
+                                currentMetadata = recomputeModifiedBuckets(transform, currentMetadata, modifiedBuckets)
+                                // Add processed buckets to 'processed set' so that we don't try to reprocess them again
+                                transformProcessedBucketLog.addBuckets(modifiedBuckets.toList())
+                                // Update TransformMetadata
+                                currentMetadata = transformMetadataService.writeMetadata(currentMetadata, true)
+                                bucketsToTransform = bucketsToTransform.copy(metadata = currentMetadata)
+                            }
                         } else {
-                            currentMetadata = executeTransformIteration(transform, currentMetadata, bucketsToTransform.modifiedBuckets)
-                            attemptedToIndex = true
+                            // Computes buckets from source index and stores them in targetIndex as transform docs
+                            currentMetadata = computeBucketsIteration(transform, currentMetadata)
+                            // Update TransformMetadata
+                            currentMetadata = transformMetadataService.writeMetadata(currentMetadata, true)
                         }
                         // we attempt to renew lock for every loop of transform
                         val renewedLock = renewLockForScheduledJob(context, lock, backoffPolicy)
@@ -159,7 +176,7 @@ object TransformRunner :
                         lock = renewedLock
                     }
                 }
-            } while (bucketsToTransform.currentShard != null || currentMetadata.afterKey != null || !attemptedToIndex)
+            } while (bucketsToTransform.currentShard != null || currentMetadata.afterKey != null)
         } catch (e: Exception) {
             logger.error("Failed to execute the transform job [${transform.id}] because of exception [${e.localizedMessage}]", e)
             currentMetadata = currentMetadata.copy(
@@ -189,6 +206,8 @@ object TransformRunner :
     private suspend fun getBucketsToTransformIteration(transform: Transform, bucketsToTransform: BucketsToTransform): BucketsToTransform {
         var currentBucketsToTransform = bucketsToTransform
         val currentShard = bucketsToTransform.currentShard
+        // Clear modified buckets from previous iteration
+        currentBucketsToTransform.modifiedBuckets.clear()
 
         if (currentShard != null) {
             val shardLevelModifiedBuckets = withTransformSecurityContext(transform) {
@@ -236,32 +255,59 @@ object TransformRunner :
      * the range query will not precisely specify the modified buckets. As a result, we increase the range for the query and then filter out
      * the unintended buckets as part of the composite search step.
      */
-    private suspend fun executeTransformIteration(
+    private suspend fun computeBucketsIteration(
+        transform: Transform,
+        metadata: TransformMetadata,
+    ): TransformMetadata {
+
+        val transformSearchResult = withTransformSecurityContext(transform) {
+            transformSearchService.executeCompositeSearch(
+                transform,
+                metadata.afterKey,
+                null
+            )
+        }
+        val indexTimeInMillis = withTransformSecurityContext(transform) {
+            transformIndexer.index(transformSearchResult.docsToIndex)
+        }
+        val afterKey = transformSearchResult.afterKey
+        val stats = transformSearchResult.stats
+        val updatedStats = stats.copy(
+            pagesProcessed = stats.pagesProcessed,
+            indexTimeInMillis = stats.indexTimeInMillis + indexTimeInMillis,
+            documentsIndexed = transformSearchResult.docsToIndex.size.toLong()
+        )
+        return metadata.mergeStats(updatedStats).copy(
+            afterKey = afterKey,
+            lastUpdatedAt = Instant.now(),
+            status = if (afterKey == null) TransformMetadata.Status.FINISHED else TransformMetadata.Status.STARTED
+        )
+    }
+
+    private suspend fun recomputeModifiedBuckets(
         transform: Transform,
         metadata: TransformMetadata,
         modifiedBuckets: MutableSet<Map<String, Any>>
     ): TransformMetadata {
-        val updatedMetadata = if (!transform.continuous || modifiedBuckets.isNotEmpty()) {
+        val updatedMetadata = if (modifiedBuckets.isNotEmpty()) {
             val transformSearchResult = withTransformSecurityContext(transform) {
-                transformSearchService.executeCompositeSearch(transform, metadata.afterKey, if (transform.continuous) modifiedBuckets else null)
+                transformSearchService.executeCompositeSearch(transform, null, modifiedBuckets)
             }
             val indexTimeInMillis = withTransformSecurityContext(transform) {
                 transformIndexer.index(transformSearchResult.docsToIndex)
             }
-            val afterKey = transformSearchResult.afterKey
             val stats = transformSearchResult.stats
             val updatedStats = stats.copy(
                 pagesProcessed = if (transform.continuous) 0 else stats.pagesProcessed,
                 indexTimeInMillis = stats.indexTimeInMillis + indexTimeInMillis,
                 documentsIndexed = transformSearchResult.docsToIndex.size.toLong()
             )
             metadata.mergeStats(updatedStats).copy(
-                afterKey = afterKey,
                 lastUpdatedAt = Instant.now(),
-                status = if (afterKey == null && !transform.continuous) TransformMetadata.Status.FINISHED else TransformMetadata.Status.STARTED
+                status = TransformMetadata.Status.STARTED
             )
         } else metadata.copy(lastUpdatedAt = Instant.now(), status = TransformMetadata.Status.STARTED)
-        return transformMetadataService.writeMetadata(updatedMetadata, true)
+        return updatedMetadata
     }
 
     private suspend fun <T> withTransformSecurityContext(transform: Transform, block: suspend CoroutineScope.() -> T): T {

src/main/kotlin/org/opensearch/indexmanagement/transform/TransformSearchService.kt

@@ -40,6 +40,7 @@ import org.opensearch.indexmanagement.transform.model.TransformSearchResult
 import org.opensearch.indexmanagement.transform.model.TransformStats
 import org.opensearch.indexmanagement.transform.settings.TransformSettings.Companion.TRANSFORM_JOB_SEARCH_BACKOFF_COUNT
 import org.opensearch.indexmanagement.transform.settings.TransformSettings.Companion.TRANSFORM_JOB_SEARCH_BACKOFF_MILLIS
+import org.opensearch.indexmanagement.util.IndexUtils.Companion.LUCENE_MAX_CLAUSES
 import org.opensearch.indexmanagement.util.IndexUtils.Companion.ODFE_MAGIC_NULL
 import org.opensearch.indexmanagement.util.IndexUtils.Companion.hashToFixedSize
 import org.opensearch.rest.RestStatus
@@ -112,10 +113,11 @@ class TransformSearchService(
     suspend fun getShardLevelModifiedBuckets(transform: Transform, afterKey: Map<String, Any>?, currentShard: ShardNewDocuments): BucketSearchResult {
         try {
             var retryAttempt = 0
+            var pageSize = calculateMaxPageSize(transform)
             val searchResponse = backoffPolicy.retry(logger) {
                 val pageSizeDecay = 2f.pow(retryAttempt++)
                 client.suspendUntil { listener: ActionListener<SearchResponse> ->
-                    val pageSize = max(1, transform.pageSize.div(pageSizeDecay.toInt()))
+                    pageSize = max(1, pageSize.div(pageSizeDecay.toInt()))
                     if (retryAttempt > 1) {
                         logger.debug(
                             "Attempt [${retryAttempt - 1}] to get modified buckets for transform [${transform.id}]. Attempting " +
@@ -139,19 +141,33 @@ class TransformSearchService(
         }
     }
 
+    /**
+     *   Apache Lucene has maxClauses limit which we could trip during recomputing of modified buckets(continuous transform)
+     *   due to trying to match too many bucket fields. To avoid this, we control how many buckets we recompute at a time(pageSize)
+     */
+    private fun calculateMaxPageSize(transform: Transform): Int {
+        return minOf(transform.pageSize, LUCENE_MAX_CLAUSES / (transform.groups.size + 1))
+    }
+
     @Suppress("RethrowCaughtException")
     suspend fun executeCompositeSearch(
         transform: Transform,
         afterKey: Map<String, Any>? = null,
         modifiedBuckets: MutableSet<Map<String, Any>>? = null
     ): TransformSearchResult {
         try {
+            var pageSize: Int =
+                if (modifiedBuckets.isNullOrEmpty())
+                    transform.pageSize
+                else
+                    modifiedBuckets.size
+
             var retryAttempt = 0
             val searchResponse = backoffPolicy.retry(logger) {
                 // TODO: Should we store the value of the past successful page size (?)
                 val pageSizeDecay = 2f.pow(retryAttempt++)
                 client.suspendUntil { listener: ActionListener<SearchResponse> ->
-                    val pageSize = max(1, transform.pageSize.div(pageSizeDecay.toInt()))
+                    pageSize = max(1, pageSize.div(pageSizeDecay.toInt()))
                     if (retryAttempt > 1) {
                         logger.debug(
                             "Attempt [${retryAttempt - 1}] of composite search failed for transform [${transform.id}]. Attempting " +

src/main/kotlin/org/opensearch/indexmanagement/util/IndexUtils.kt

@@ -33,6 +33,7 @@ class IndexUtils {
         const val SCHEMA_VERSION = "schema_version"
         const val DEFAULT_SCHEMA_VERSION = 1L
         const val ODFE_MAGIC_NULL = "#ODFE-MAGIC-NULL-MAGIC-ODFE#"
+        const val LUCENE_MAX_CLAUSES = 1024
         private const val BYTE_ARRAY_SIZE = 16
         private const val DOCUMENT_ID_SEED = 72390L
 

src/test/kotlin/org/opensearch/indexmanagement/transform/TransformRunnerIT.kt

@@ -7,6 +7,8 @@ package org.opensearch.indexmanagement.transform
 
 import org.apache.http.entity.ContentType
 import org.apache.http.entity.StringEntity
+import org.opensearch.client.Request
+import org.opensearch.client.RequestOptions
 import org.opensearch.common.settings.Settings
 import org.opensearch.index.query.TermQueryBuilder
 import org.opensearch.indexmanagement.common.model.dimension.DateHistogram
@@ -44,7 +46,7 @@ class TransformRunnerIT : TransformRestTestCase() {
             sourceIndex = "transform-source-index",
             targetIndex = "transform-target-index",
             roles = emptyList(),
-            pageSize = 100,
+            pageSize = 1,
             groups = listOf(
                 Terms(sourceField = "store_and_fwd_flag", targetField = "flag")
             )
@@ -62,7 +64,7 @@ class TransformRunnerIT : TransformRestTestCase() {
             transformMetadata
         }
 
-        assertEquals("More than expected pages processed", 2L, metadata.stats.pagesProcessed)
+        assertEquals("More than expected pages processed", 3L, metadata.stats.pagesProcessed)
         assertEquals("More than expected documents indexed", 2L, metadata.stats.documentsIndexed)
         assertEquals("More than expected documents processed", 5000L, metadata.stats.documentsProcessed)
         assertTrue("Doesn't capture indexed time", metadata.stats.indexTimeInMillis > 0)
@@ -84,7 +86,7 @@ class TransformRunnerIT : TransformRestTestCase() {
             sourceIndex = "transform-source-index",
             targetIndex = "transform-target-index",
             roles = emptyList(),
-            pageSize = 100,
+            pageSize = 1,
             groups = listOf(
                 Terms(sourceField = "store_and_fwd_flag", targetField = "flag")
             ),
@@ -950,6 +952,70 @@ class TransformRunnerIT : TransformRestTestCase() {
         }
     }
 
+    fun `test continuous transform with a lot of buckets`() {
+
+        // Create index with high cardinality fields
+        val sourceIndex = "index_with_lots_of_buckets"
+
+        val requestBody: StringBuilder = StringBuilder(100000)
+        for (i in 1..2000) {
+            val docPayload: String = """
+            {
+              "id1": "$i",
+              "id2": "${i + 1}"
+            }
+            """.trimIndent().replace(Regex("[\n\r\\s]"), "")
+
+            requestBody.append("{\"create\":{}}\n").append(docPayload).append('\n')
+        }
+
+        createIndexAndBulkInsert(sourceIndex, Settings.EMPTY, null, null, requestBody.toString())
+        // Source index will have total of 2000 buckets
+        val transform = Transform(
+            id = "transform_index_with_lots_of_buckets",
+            schemaVersion = 1L,
+            enabled = true,
+            enabledAt = Instant.now(),
+            updatedAt = Instant.now(),
+            jobSchedule = IntervalSchedule(Instant.now(), 1, ChronoUnit.MINUTES),
+            description = "test transform",
+            metadataId = null,
+            sourceIndex = "index_with_lots_of_buckets",
+            targetIndex = "index_with_lots_of_buckets_transformed",
+            roles = emptyList(),
+            pageSize = 1000,
+            groups = listOf(
+                Terms(sourceField = "id1.keyword", targetField = "id1"),
+                Terms(sourceField = "id2.keyword", targetField = "id2")
+            ),
+            continuous = true
+        ).let { createTransform(it, it.id) }
+
+        updateTransformStartTime(transform)
+
+        waitFor { assertTrue("Target transform index was not created", indexExists(transform.targetIndex)) }
+
+        val firstIterationMetadata = waitFor {
+            val job = getTransform(transformId = transform.id)
+            assertNotNull("Transform job doesn't have metadata set", job.metadataId)
+            val transformMetadata = getTransformMetadata(job.metadataId!!)
+            assertEquals("Transform did not complete iteration or had incorrect number of documents processed", 2000, transformMetadata.stats.documentsProcessed)
+            assertEquals("Transform did not complete iteration", null, transformMetadata.afterKey)
+            assertNotNull("Continuous stats were not updated", transformMetadata.continuousStats)
+            assertNotNull("Continuous stats were set, but lastTimestamp was not", transformMetadata.continuousStats!!.lastTimestamp)
+            transformMetadata
+        }
+
+        assertEquals("Not the expected transform status", TransformMetadata.Status.STARTED, firstIterationMetadata.status)
+        assertEquals("Not the expected pages processed", 7, firstIterationMetadata.stats.pagesProcessed)
+        assertEquals("Not the expected documents indexed", 2000L, firstIterationMetadata.stats.documentsIndexed)
+        assertEquals("Not the expected documents processed", 2000L, firstIterationMetadata.stats.documentsProcessed)
+        assertTrue("Doesn't capture indexed time", firstIterationMetadata.stats.indexTimeInMillis > 0)
+        assertTrue("Didn't capture search time", firstIterationMetadata.stats.searchTimeInMillis > 0)
+
+        disableTransform(transform.id)
+    }
+
     private fun getStrictMappings(): String {
         return """
             "dynamic": "strict",
@@ -967,4 +1033,21 @@ class TransformRunnerIT : TransformRestTestCase() {
             assertIndexExists(indexName)
         }
     }
+
+    private fun createIndexAndBulkInsert(name: String, settings: Settings?, mapping: String?, aliases: String?, bulkData: String) {
+
+        if (settings != null || mapping != null || aliases != null) {
+            createIndex(name, settings, mapping, aliases)
+        }
+
+        val request = Request("POST", "/$name/_bulk/?refresh=true")
+        request.setJsonEntity(bulkData)
+        request.options = RequestOptions.DEFAULT.toBuilder().addHeader("content-type", "application/x-ndjson").build()
+        var res = client().performRequest(request)
+        assertEquals(RestStatus.OK, res.restStatus())
+
+        val refreshRequest = Request("POST", "/$name/_refresh")
+        res = client().performRequest(refreshRequest)
+        assertEquals(RestStatus.OK, res.restStatus())
+    }
 }