orders is reduced by a factor of 5. Constraining the planner’s search in this way is a useful technique both for reducing planning time and for directing the planner to a good query plan. If the planner way, it will not need subsequent vacu- uming to avoid transaction ID wraparound problems. This technique is used by initdb to prepare the template0 database. It should also be used to prepare any user-created Read your file system documentation very carefully before trusting to the consistent-snapshot technique in such situations. The safest approach is to shut down the database server for long enough to establish

211 Chapter 13. Performance Tips Constraining the planner’s search in this way is a useful technique both for reducing planning time and for directing the planner to a good query plan. If the planner way, it will not need subsequent vac- uuming to avoid transaction ID wraparound problems. This technique is used by initdb to prepare the template0 database. It should also be used to prepare any user-created at any point and have a consistent snapshot of the database as it was at that time. Thus, this technique supports point-in-time recovery: it is possible to restore the database to its state at any time

dataset. 5.9.3. Partitioning and Constraint Exclusion Constraint exclusion is a query optimization technique that improves performance for partitioned tables defined in the fashion described above. As an example: orders is reduced by a factor of 5. Constraining the planner’s search in this way is a useful technique both for reducing planning time and for directing the planner to a good query plan. If the planner way, it will not need subsequent vacu- uming to avoid transaction ID wraparound problems. This technique is used by initdb to prepare the template0 database. It should also be used to prepare any user-created

dataset. 5.9.3. Partitioning and Constraint Exclusion Constraint exclusion is a query optimization technique that improves performance for partitioned tables defined in the fashion described above. As an example: orders is reduced by a factor of 5. Constraining the planner’s search in this way is a useful technique both for reducing planning time and for directing the planner to a good query plan. If the planner way, it will not need subsequent vacu- uming to avoid transaction ID wraparound problems. This technique is used by initdb to prepare the template0 database. It should also be used to prepare any user-created

.................................................................2102 61.4.1. GIN Fast Update Technique...................................................................2102 61.4.2. Partial Match Algorithm writing y > 1.5*x instead.) CASE is not a cure-all for such issues, however. One limitation of the technique illustrated above is that it does not prevent early evaluation of constant subexpressions. As described measurement; 5.10.4. Partitioning and Constraint Exclusion Constraint exclusion is a query optimization technique that improves performance for partitioned tables defined in the fashion described above. As an example:

.................................................................2230 61.4.1. GIN Fast Update Technique..........................................................................2230 61.4.2. Partial Match writing y > 1.5*x instead.) CASE is not a cure-all for such issues, however. One limitation of the technique illustrated above is that it does not prevent early evaluation of constant subexpressions. As described measurement; 5.10.4. Partitioning and Constraint Exclusion Constraint exclusion is a query optimization technique that improves performance for partitioned tables defined in the fashion described above. As an example:

writing y > 1.5*x instead.) CASE is not a cure-all for such issues, however. One limitation of the technique illustrated above is that it does not prevent early evaluation of constant subexpressions. As described (unitsales); ALTER INDEX measurement_usls_idx ATTACH PARTITION measurement_usls_200602_idx; ... This technique can be used with UNIQUE and PRIMARY KEY constraints too; the indexes are created implicitly when declarative partitioning. 5.11.4. Partition Pruning Partition pruning is a query optimization technique that improves performance for declaratively parti- tioned tables. As an example: SET enable_partition_pruning

writing y > 1.5*x instead.) CASE is not a cure-all for such issues, however. One limitation of the technique illustrated above is that it does not prevent early evaluation of constant subexpressions. As described (unitsales); ALTER INDEX measurement_usls_idx ATTACH PARTITION measurement_usls_200602_idx; ... This technique can be used with UNIQUE and PRIMARY KEY constraints too; the indexes are created implicitly when declarative partitioning. 5.11.4. Partition Pruning Partition pruning is a query optimization technique that improves performance for declaratively par- titioned tables. As an example: SET enable_partition_pruning

measurement; 5.9.4. Partitioning and Constraint Exclusion Constraint exclusion is a query optimization technique that improves performance for partitioned tables defined in the fashion described above. As an example: orders is reduced by a factor of 5. Constraining the planner’s search in this way is a useful technique both for reducing planning time and for directing the planner to a good query plan. If the planner very carefully 376 Chapter 23. Backup and Restore before trusting to the consistent-snapshot technique in such situations. The safest approach is to shut down the database server for long enough to establish

writing y > 1.5*x instead.) CASE is not a cure-all for such issues, however. One limitation of the technique illustrated above is that it does not prevent early evaluation of constant subexpressions. As described (unitsales); ALTER INDEX measurement_usls_idx ATTACH PARTITION measurement_usls_200602_idx; ... This technique can be used with UNIQUE and PRIMARY KEY constraints too; the indexes are created implicitly when declarative partitioning. 5.11.4. Partition Pruning Partition pruning is a query optimization technique that improves performance for declaratively par- titioned tables. As an example: SET enable_partition_pruning