| 1 | /* |
| 2 | |
| 3 | Derby - Class org.apache.derby.impl.store.access.sort.MergeInserter |
| 4 | |
| 5 | Copyright 1997, 2004 The Apache Software Foundation or its licensors, as applicable. |
| 6 | |
| 7 | Licensed under the Apache License, Version 2.0 (the "License"); |
| 8 | you may not use this file except in compliance with the License. |
| 9 | You may obtain a copy of the License at |
| 10 | |
| 11 | http://www.apache.org/licenses/LICENSE-2.0 |
| 12 | |
| 13 | Unless required by applicable law or agreed to in writing, software |
| 14 | distributed under the License is distributed on an "AS IS" BASIS, |
| 15 | WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| 16 | See the License for the specific language governing permissions and |
| 17 | limitations under the License. |
| 18 | |
| 19 | */ |
| 20 | |
| 21 | package org.apache.derby.impl.store.access.sort; |
| 22 | |
| 23 | import java.util.Vector; |
| 24 | import org.apache.derby.iapi.services.sanity.SanityManager; |
| 25 | import org.apache.derby.iapi.services.io.Storable; |
| 26 | import org.apache.derby.iapi.error.StandardException; |
| 27 | import org.apache.derby.iapi.store.access.conglomerate.TransactionManager; |
| 28 | import org.apache.derby.iapi.store.access.ColumnOrdering; |
| 29 | import org.apache.derby.iapi.store.access.ConglomerateController; |
| 30 | import org.apache.derby.iapi.store.access.Qualifier; |
| 31 | import org.apache.derby.iapi.store.access.ScanController; |
| 32 | import org.apache.derby.iapi.store.access.SortController; |
| 33 | import org.apache.derby.iapi.store.access.SortInfo; |
| 34 | import org.apache.derby.iapi.store.access.TransactionController; |
| 35 | |
| 36 | import org.apache.derby.iapi.types.DataValueDescriptor; |
| 37 | |
| 38 | import org.apache.derby.iapi.types.RowLocation; |
| 39 | |
| 40 | /** |
| 41 | |
| 42 | |
| 43 | **/ |
| 44 | |
| 45 | public final class MergeInserter implements SortController |
| 46 | { |
| 47 | /** |
| 48 | The sort this inserter is for. |
| 49 | **/ |
| 50 | protected MergeSort sort = null; |
| 51 | |
| 52 | /** |
| 53 | The transaction this inserter is in. |
| 54 | **/ |
| 55 | protected TransactionManager tran; |
| 56 | |
| 57 | /** |
| 58 | A vector of the conglomerate ids of the merge runs. |
| 59 | **/ |
| 60 | Vector mergeRuns = null; |
| 61 | |
| 62 | /** |
| 63 | An in-memory ordered set that is used to sort rows |
| 64 | before they're sent to merge runs. |
| 65 | **/ |
| 66 | SortBuffer sortBuffer = null; |
| 67 | |
| 68 | /** |
| 69 | Information about memory usage to dynamically tune the |
| 70 | in-memory sort buffer size. |
| 71 | */ |
| 72 | long beginFreeMemory; |
| 73 | long beginTotalMemory; |
| 74 | long estimatedMemoryUsed; |
| 75 | boolean avoidMergeRun; // try to avoid merge run if possible |
| 76 | int runSize; |
| 77 | int totalRunSize; |
| 78 | |
| 79 | protected String stat_sortType; |
| 80 | protected int stat_numRowsInput; |
| 81 | protected int stat_numRowsOutput; |
| 82 | protected int stat_numMergeRuns; |
| 83 | protected Vector stat_mergeRunsSize; |
| 84 | |
| 85 | |
| 86 | /* |
| 87 | * Methods of SortController |
| 88 | */ |
| 89 | |
| 90 | /** |
| 91 | Insert a row into the sort. |
| 92 | @see SortController#insert |
| 93 | **/ |
| 94 | public void insert(DataValueDescriptor[] row) |
| 95 | throws StandardException |
| 96 | { |
| 97 | if (SanityManager.DEBUG) |
| 98 | { |
| 99 | // If the sort is null, probably the caller forgot |
| 100 | // to call initialize. |
| 101 | SanityManager.ASSERT(sort != null); |
| 102 | } |
| 103 | |
| 104 | // Check that the inserted row is of the correct type |
| 105 | sort.checkColumnTypes(row); |
| 106 | |
| 107 | // Insert the row into the sort buffer, which will |
| 108 | // sort it into the right order with the rest of the |
| 109 | // rows and remove any duplicates. |
| 110 | int insertResult = sortBuffer.insert(row); |
| 111 | stat_numRowsInput++; |
| 112 | if (insertResult != SortBuffer.INSERT_DUPLICATE) |
| 113 | stat_numRowsOutput++; |
| 114 | if (insertResult == SortBuffer.INSERT_FULL) |
| 115 | { |
| 116 | if (avoidMergeRun) |
| 117 | { |
| 118 | Runtime jvm = Runtime.getRuntime(); |
| 119 | if (SanityManager.DEBUG) |
| 120 | { |
| 121 | if (SanityManager.DEBUG_ON("SortTuning")) |
| 122 | { |
| 123 | jvm.gc(); |
| 124 | jvm.gc(); |
| 125 | jvm.gc(); |
| 126 | } |
| 127 | } |
| 128 | |
| 129 | long currentFreeMemory = jvm.freeMemory(); |
| 130 | long currentTotalMemory = jvm.totalMemory(); |
| 131 | |
| 132 | // before we create an external sort, which is expensive, see if |
| 133 | // we can use up more in-memory sort buffer |
| 134 | // we see how much memory has been used between now and the |
| 135 | // beginning of the sort. Not all of this memory is used by |
| 136 | // the sort and GC may have kicked in and release some memory. |
| 137 | // But it is a rough guess. |
| 138 | estimatedMemoryUsed = (currentTotalMemory-currentFreeMemory) - |
| 139 | (beginTotalMemory-beginFreeMemory); |
| 140 | |
| 141 | if (SanityManager.DEBUG) |
| 142 | { |
| 143 | if (SanityManager.DEBUG_ON("SortTuning")) |
| 144 | { |
| 145 | SanityManager.DEBUG("SortTuning", |
| 146 | "Growing sortBuffer dynamically, " + |
| 147 | "current sortBuffer capacity= " + |
| 148 | sortBuffer.capacity() + |
| 149 | " estimatedMemoryUsed = " + estimatedMemoryUsed + |
| 150 | " currentTotalMemory = " + currentTotalMemory + |
| 151 | " currentFreeMemory = " + currentFreeMemory + |
| 152 | " numcolumn = " + row.length + |
| 153 | " real per row memory = " + |
| 154 | (estimatedMemoryUsed / sortBuffer.capacity())); |
| 155 | } |
| 156 | } |
| 157 | |
| 158 | // we want to double the sort buffer size if that will result |
| 159 | // in the sort to use up no more than 1/2 of all the free |
| 160 | // memory (including the sort memory) |
| 161 | // or if GC is so effective we are now using less memory than before |
| 162 | // or if we are using less than 1Meg of memory and the jvm is |
| 163 | // using < 5 meg of memory (this indicates that the JVM can |
| 164 | // afford to be more bloated ?) |
| 165 | if (estimatedMemoryUsed < 0 || |
| 166 | ((2*estimatedMemoryUsed) < (estimatedMemoryUsed+currentFreeMemory)/2) || |
| 167 | (2*estimatedMemoryUsed < ExternalSortFactory.DEFAULT_MEM_USE && |
| 168 | currentTotalMemory < (5*1024*1024))) |
| 169 | { |
| 170 | // ok, double the sort buffer size |
| 171 | sortBuffer.grow(100); |
| 172 | |
| 173 | if (sortBuffer.insert(row) != SortBuffer.INSERT_FULL) |
| 174 | return; |
| 175 | } |
| 176 | |
| 177 | avoidMergeRun = false; // once we did it, too late to do in |
| 178 | // memory sort |
| 179 | } |
| 180 | |
| 181 | // The sort buffer became full. Empty it into a |
| 182 | // merge run, and add the merge run to the vector |
| 183 | // of merge runs. |
| 184 | stat_sortType = "external"; |
| 185 | long conglomid = sort.createMergeRun(tran, sortBuffer); |
| 186 | if (mergeRuns == null) |
| 187 | mergeRuns = new Vector(); |
| 188 | mergeRuns.addElement(new Long(conglomid)); |
| 189 | |
| 190 | stat_numMergeRuns++; |
| 191 | // calculate size of this merge run |
| 192 | // buffer was too full for last row |
| 193 | runSize = stat_numRowsInput - totalRunSize - 1; |
| 194 | totalRunSize += runSize; |
| 195 | stat_mergeRunsSize.addElement(new Integer(runSize)); |
| 196 | |
| 197 | // Re-insert the row into the sort buffer. |
| 198 | // This is guaranteed to work since the sort |
| 199 | // buffer has just been emptied. |
| 200 | sortBuffer.insert(row); |
| 201 | } |
| 202 | } |
| 203 | |
| 204 | /** |
| 205 | Close this sort controller. Closing the sort controller |
| 206 | means the caller is done inserting rows. This method |
| 207 | must not throw any exceptions since it's called during |
| 208 | error processing. |
| 209 | |
| 210 | @see SortController#close |
| 211 | **/ |
| 212 | |
| 213 | public void close() |
| 214 | { |
| 215 | // Tell the sort that we're closed, and hand off |
| 216 | // the sort buffer and the vector of merge runs. |
| 217 | if (sort != null) |
| 218 | sort.doneInserting(this, sortBuffer, mergeRuns); |
| 219 | |
| 220 | // if this is an external sort, there will actually |
| 221 | // be one last merge run with the contents of the |
| 222 | // current sortBuffer. It will be created when the user |
| 223 | // reads the result of the sort using openSortScan |
| 224 | if (stat_sortType == "external") |
| 225 | { |
| 226 | stat_numMergeRuns++; |
| 227 | stat_mergeRunsSize.addElement(new Integer(stat_numRowsInput - totalRunSize)); |
| 228 | } |
| 229 | |
| 230 | // close the SortController in the transaction. |
| 231 | tran.closeMe(this); |
| 232 | |
| 233 | // Clean up. |
| 234 | sort = null; |
| 235 | tran = null; |
| 236 | mergeRuns = null; |
| 237 | sortBuffer = null; |
| 238 | } |
| 239 | |
| 240 | /* |
| 241 | * Methods of MergeInserter. Arranged alphabetically. |
| 242 | */ |
| 243 | |
| 244 | /** |
| 245 | * Return SortInfo object which contains information about the current |
| 246 | * sort. |
| 247 | * <p> |
| 248 | * |
| 249 | * @see SortInfo |
| 250 | * |
| 251 | * @return The SortInfo object which contains info about current sort. |
| 252 | * |
| 253 | * @exception StandardException Standard exception policy. |
| 254 | **/ |
| 255 | public SortInfo getSortInfo() |
| 256 | throws StandardException |
| 257 | { |
| 258 | return(new MergeSortInfo(this)); |
| 259 | } |
| 260 | |
| 261 | |
| 262 | /** |
| 263 | Initialize this inserter. |
| 264 | @return true if initialization was successful |
| 265 | **/ |
| 266 | boolean initialize(MergeSort sort, TransactionManager tran) |
| 267 | { |
| 268 | Runtime jvm = Runtime.getRuntime(); |
| 269 | if (SanityManager.DEBUG) |
| 270 | { |
| 271 | if (SanityManager.DEBUG_ON("SortTuning")) |
| 272 | { |
| 273 | jvm.gc(); |
| 274 | jvm.gc(); |
| 275 | jvm.gc(); |
| 276 | } |
| 277 | } |
| 278 | |
| 279 | beginFreeMemory = jvm.freeMemory(); |
| 280 | beginTotalMemory = jvm.totalMemory(); |
| 281 | estimatedMemoryUsed = 0; |
| 282 | avoidMergeRun = true; // not an external sort |
| 283 | stat_sortType = "internal"; |
| 284 | stat_numMergeRuns = 0; |
| 285 | stat_numRowsInput = 0; |
| 286 | stat_numRowsOutput = 0; |
| 287 | stat_mergeRunsSize = new Vector(); |
| 288 | runSize = 0; |
| 289 | totalRunSize = 0; |
| 290 | |
| 291 | |
| 292 | if (SanityManager.DEBUG) |
| 293 | { |
| 294 | if (SanityManager.DEBUG_ON("testSort")) |
| 295 | { |
| 296 | avoidMergeRun = false; |
| 297 | } |
| 298 | } |
| 299 | |
| 300 | this.sort = sort; |
| 301 | this.tran = tran; |
| 302 | sortBuffer = new SortBuffer(sort); |
| 303 | if (sortBuffer.init() == false) |
| 304 | return false; |
| 305 | return true; |
| 306 | } |
| 307 | |
| 308 | } |