Relax strong table lock when refreshing a Continuous Aggregate#5809
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@shhnwz, @gayyappan: please review this pull request.
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mkindahl
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I think the test does not test what you expect. Also, I wonder if you need to have the isolation test for this race condition since the continuous aggregate creation seem to block on the trigger creation before reaching the potential race condition.
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The waitpoint is not used, but I suspect that you do not need it anyway since the two create statements block on creating the trigger.
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Implementation looks good. I am wondering about why some of the statements in the isolation tests are not waiting since that suggests that there is no race condition to test, but I do not think this should block a merge.
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When refreshing a Continuous Aggregate we take a table lock on _timescaledb_catalog.continuous_aggs_invalidation_threshold when processing the invalidation logs (the first transaction of the refresh Continuous Aggregate procedure). It means that even two different Continuous Aggregates over two different hypertables will wait each other in the first phase of the refreshing procedure. Also it lead to problems when a pg_dump is running because it take an AccessShareLock on tables so Continuous Aggregate refresh execution will wait until the pg_dump finish. Improved it by relaxing the strong table-level lock to a row-level lock so now the Continuous Aggregate refresh procedure can be executed in multiple sessions with less locks. Fix timescale#3554
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Hey @fabriziomello, thanks for your work on this! I wanted to ask if this will close the ticket mentioned here #5880 i.e concurrent refreshes of a C-Agg on disjoint time ranges ? |
This release contains performance improvements for compressed hypertables and continuous aggregates and bug fixes since the 2.11.2 release. We recommend that you upgrade at the next available opportunity. This release moves all internal functions from the _timescaleb_internal schema into the _timescaledb_functions schema. This separates code from internal data objects and improves security by allowing more restrictive permissions for the code schema. If you are calling any of those internal functions you should adjust your code as soon as possible. This version also includes a compatibility layer that allows calling them in the old location but that layer will be removed in 2.14.0. **PostgreSQL 12 support removal announcement** Following the deprecation announcement for PostgreSQL 12 in TimescaleDB 2.10, PostgreSQL 12 is not supported starting with TimescaleDB 2.12. Currently supported PostgreSQL major versions are 13, 14 and 15. PostgreSQL 16 support will be added with a following TimescaleDB release. **Features** * timescale#5137 Insert into index during chunk compression * timescale#5150 MERGE support on hypertables * timescale#5515 Make hypertables support replica identity * timescale#5586 Index scan support during UPDATE/DELETE on compressed hypertables * timescale#5596 Support for partial aggregations at chunk level * timescale#5599 Enable ChunkAppend for partially compressed chunks * timescale#5655 Improve the number of parallel workers for decompression * timescale#5758 Enable altering job schedule type through `alter_job` * timescale#5805 Make logrepl markers for (partial) decompressions * timescale#5809 Relax invalidation threshold table-level lock to row-level when refreshing a Continuous Aggregate * timescale#5839 Support CAgg names in chunk_detailed_size * timescale#5852 Make set_chunk_time_interval CAggs aware * timescale#5868 Allow ALTER TABLE ... REPLICA IDENTITY (FULL|INDEX) on materialized hypertables (continuous aggregates) * timescale#5875 Add job exit status and runtime to log * timescale#5909 CREATE INDEX ONLY ON hypertable creates index on chunks **Bugfixes** * timescale#5860 Fix interval calculation for hierarchical CAggs * timescale#5894 Check unique indexes when enabling compression * timescale#5951 _timescaledb_internal.create_compressed_chunk doesn't account for existing uncompressed rows * timescale#5988 Move functions to _timescaledb_functions schema * timescale#5788 Chunk_create must add an existing table or fail * timescale#5872 Fix duplicates on partially compressed chunk reads * timescale#5918 Fix crash in COPY from program returning error * timescale#5990 Place data in first/last function in correct mctx * timescale#5991 Call eq_func correctly in time_bucket_gapfill * timescale#6015 Correct row count in EXPLAIN ANALYZE INSERT .. ON CONFLICT output * timescale#6035 Fix server crash on UPDATE of compressed chunk * timescale#6044 Fix server crash when using duplicate segmentby column * timescale#6045 Fix segfault in set_integer_now_func * timescale#6053 Fix approximate_row_count for CAggs * timescale#6081 Improve compressed DML datatype handling * timescale#6084 Propagate parameter changes to decompress child nodes **Thanks** * @ajcanterbury for reporting a problem with lateral joins on compressed chunks * @alexanderlaw for reporting multiple server crashes * @lukaskirner for reporting a bug with monthly continuous aggregates * @mrksngl for reporting a bug with unusual user names * @willsbit for reporting a crash in time_bucket_gapfill
This release contains performance improvements for compressed hypertables and continuous aggregates and bug fixes since the 2.11.2 release. We recommend that you upgrade at the next available opportunity. This release moves all internal functions from the _timescaleb_internal schema into the _timescaledb_functions schema. This separates code from internal data objects and improves security by allowing more restrictive permissions for the code schema. If you are calling any of those internal functions you should adjust your code as soon as possible. This version also includes a compatibility layer that allows calling them in the old location but that layer will be removed in 2.14.0. **PostgreSQL 12 support removal announcement** Following the deprecation announcement for PostgreSQL 12 in TimescaleDB 2.10, PostgreSQL 12 is not supported starting with TimescaleDB 2.12. Currently supported PostgreSQL major versions are 13, 14 and 15. PostgreSQL 16 support will be added with a following TimescaleDB release. **Features** * #5137 Insert into index during chunk compression * #5150 MERGE support on hypertables * #5515 Make hypertables support replica identity * #5586 Index scan support during UPDATE/DELETE on compressed hypertables * #5596 Support for partial aggregations at chunk level * #5599 Enable ChunkAppend for partially compressed chunks * #5655 Improve the number of parallel workers for decompression * #5758 Enable altering job schedule type through `alter_job` * #5805 Make logrepl markers for (partial) decompressions * #5809 Relax invalidation threshold table-level lock to row-level when refreshing a Continuous Aggregate * #5839 Support CAgg names in chunk_detailed_size * #5852 Make set_chunk_time_interval CAggs aware * #5868 Allow ALTER TABLE ... REPLICA IDENTITY (FULL|INDEX) on materialized hypertables (continuous aggregates) * #5875 Add job exit status and runtime to log * #5909 CREATE INDEX ONLY ON hypertable creates index on chunks **Bugfixes** * #5860 Fix interval calculation for hierarchical CAggs * #5894 Check unique indexes when enabling compression * #5951 _timescaledb_internal.create_compressed_chunk doesn't account for existing uncompressed rows * #5988 Move functions to _timescaledb_functions schema * #5788 Chunk_create must add an existing table or fail * #5872 Fix duplicates on partially compressed chunk reads * #5918 Fix crash in COPY from program returning error * #5990 Place data in first/last function in correct mctx * #5991 Call eq_func correctly in time_bucket_gapfill * #6015 Correct row count in EXPLAIN ANALYZE INSERT .. ON CONFLICT output * #6035 Fix server crash on UPDATE of compressed chunk * #6044 Fix server crash when using duplicate segmentby column * #6045 Fix segfault in set_integer_now_func * #6053 Fix approximate_row_count for CAggs * #6081 Improve compressed DML datatype handling * #6084 Propagate parameter changes to decompress child nodes **Thanks** * @ajcanterbury for reporting a problem with lateral joins on compressed chunks * @alexanderlaw for reporting multiple server crashes * @lukaskirner for reporting a bug with monthly continuous aggregates * @mrksngl for reporting a bug with unusual user names * @willsbit for reporting a crash in time_bucket_gapfill
This release contains performance improvements for compressed hypertables and continuous aggregates and bug fixes since the 2.11.2 release. We recommend that you upgrade at the next available opportunity. This release moves all internal functions from the _timescaleb_internal schema into the _timescaledb_functions schema. This separates code from internal data objects and improves security by allowing more restrictive permissions for the code schema. If you are calling any of those internal functions you should adjust your code as soon as possible. This version also includes a compatibility layer that allows calling them in the old location but that layer will be removed in 2.14.0. **PostgreSQL 12 support removal announcement** Following the deprecation announcement for PostgreSQL 12 in TimescaleDB 2.10, PostgreSQL 12 is not supported starting with TimescaleDB 2.12. Currently supported PostgreSQL major versions are 13, 14 and 15. PostgreSQL 16 support will be added with a following TimescaleDB release. **Features** * #5137 Insert into index during chunk compression * #5150 MERGE support on hypertables * #5515 Make hypertables support replica identity * #5586 Index scan support during UPDATE/DELETE on compressed hypertables * #5596 Support for partial aggregations at chunk level * #5599 Enable ChunkAppend for partially compressed chunks * #5655 Improve the number of parallel workers for decompression * #5758 Enable altering job schedule type through `alter_job` * #5805 Make logrepl markers for (partial) decompressions * #5809 Relax invalidation threshold table-level lock to row-level when refreshing a Continuous Aggregate * #5839 Support CAgg names in chunk_detailed_size * #5852 Make set_chunk_time_interval CAggs aware * #5868 Allow ALTER TABLE ... REPLICA IDENTITY (FULL|INDEX) on materialized hypertables (continuous aggregates) * #5875 Add job exit status and runtime to log * #5909 CREATE INDEX ONLY ON hypertable creates index on chunks **Bugfixes** * #5860 Fix interval calculation for hierarchical CAggs * #5894 Check unique indexes when enabling compression * #5951 _timescaledb_internal.create_compressed_chunk doesn't account for existing uncompressed rows * #5988 Move functions to _timescaledb_functions schema * #5788 Chunk_create must add an existing table or fail * #5872 Fix duplicates on partially compressed chunk reads * #5918 Fix crash in COPY from program returning error * #5990 Place data in first/last function in correct mctx * #5991 Call eq_func correctly in time_bucket_gapfill * #6015 Correct row count in EXPLAIN ANALYZE INSERT .. ON CONFLICT output * #6035 Fix server crash on UPDATE of compressed chunk * #6044 Fix server crash when using duplicate segmentby column * #6045 Fix segfault in set_integer_now_func * #6053 Fix approximate_row_count for CAggs * #6081 Improve compressed DML datatype handling * #6084 Propagate parameter changes to decompress child nodes **Thanks** * @ajcanterbury for reporting a problem with lateral joins on compressed chunks * @alexanderlaw for reporting multiple server crashes * @lukaskirner for reporting a bug with monthly continuous aggregates * @mrksngl for reporting a bug with unusual user names * @willsbit for reporting a crash in time_bucket_gapfill
This release contains performance improvements for compressed hypertables and continuous aggregates and bug fixes since the 2.11.2 release. We recommend that you upgrade at the next available opportunity. This release moves all internal functions from the _timescaleb_internal schema into the _timescaledb_functions schema. This separates code from internal data objects and improves security by allowing more restrictive permissions for the code schema. If you are calling any of those internal functions you should adjust your code as soon as possible. This version also includes a compatibility layer that allows calling them in the old location but that layer will be removed in 2.14.0. **PostgreSQL 12 support removal announcement** Following the deprecation announcement for PostgreSQL 12 in TimescaleDB 2.10, PostgreSQL 12 is not supported starting with TimescaleDB 2.12. Currently supported PostgreSQL major versions are 13, 14 and 15. PostgreSQL 16 support will be added with a following TimescaleDB release. **Features** * #5137 Insert into index during chunk compression * #5150 MERGE support on hypertables * #5515 Make hypertables support replica identity * #5586 Index scan support during UPDATE/DELETE on compressed hypertables * #5596 Support for partial aggregations at chunk level * #5599 Enable ChunkAppend for partially compressed chunks * #5655 Improve the number of parallel workers for decompression * #5758 Enable altering job schedule type through `alter_job` * #5805 Make logrepl markers for (partial) decompressions * #5809 Relax invalidation threshold table-level lock to row-level when refreshing a Continuous Aggregate * #5839 Support CAgg names in chunk_detailed_size * #5852 Make set_chunk_time_interval CAggs aware * #5868 Allow ALTER TABLE ... REPLICA IDENTITY (FULL|INDEX) on materialized hypertables (continuous aggregates) * #5875 Add job exit status and runtime to log * #5909 CREATE INDEX ONLY ON hypertable creates index on chunks **Bugfixes** * #5860 Fix interval calculation for hierarchical CAggs * #5894 Check unique indexes when enabling compression * #5951 _timescaledb_internal.create_compressed_chunk doesn't account for existing uncompressed rows * #5988 Move functions to _timescaledb_functions schema * #5788 Chunk_create must add an existing table or fail * #5872 Fix duplicates on partially compressed chunk reads * #5918 Fix crash in COPY from program returning error * #5990 Place data in first/last function in correct mctx * #5991 Call eq_func correctly in time_bucket_gapfill * #6015 Correct row count in EXPLAIN ANALYZE INSERT .. ON CONFLICT output * #6035 Fix server crash on UPDATE of compressed chunk * #6044 Fix server crash when using duplicate segmentby column * #6045 Fix segfault in set_integer_now_func * #6053 Fix approximate_row_count for CAggs * #6081 Improve compressed DML datatype handling * #6084 Propagate parameter changes to decompress child nodes **Thanks** * @ajcanterbury for reporting a problem with lateral joins on compressed chunks * @alexanderlaw for reporting multiple server crashes * @lukaskirner for reporting a bug with monthly continuous aggregates * @mrksngl for reporting a bug with unusual user names * @willsbit for reporting a crash in time_bucket_gapfill
This release contains performance improvements for compressed hypertables and continuous aggregates and bug fixes since the 2.11.2 release. We recommend that you upgrade at the next available opportunity. This release moves all internal functions from the _timescaleb_internal schema into the _timescaledb_functions schema. This separates code from internal data objects and improves security by allowing more restrictive permissions for the code schema. If you are calling any of those internal functions you should adjust your code as soon as possible. This version also includes a compatibility layer that allows calling them in the old location but that layer will be removed in 2.14.0. **PostgreSQL 12 support removal announcement** Following the deprecation announcement for PostgreSQL 12 in TimescaleDB 2.10, PostgreSQL 12 is not supported starting with TimescaleDB 2.12. Currently supported PostgreSQL major versions are 13, 14 and 15. PostgreSQL 16 support will be added with a following TimescaleDB release. **Features** * #5137 Insert into index during chunk compression * #5150 MERGE support on hypertables * #5515 Make hypertables support replica identity * #5586 Index scan support during UPDATE/DELETE on compressed hypertables * #5596 Support for partial aggregations at chunk level * #5599 Enable ChunkAppend for partially compressed chunks * #5655 Improve the number of parallel workers for decompression * #5758 Enable altering job schedule type through `alter_job` * #5805 Make logrepl markers for (partial) decompressions * #5809 Relax invalidation threshold table-level lock to row-level when refreshing a Continuous Aggregate * #5839 Support CAgg names in chunk_detailed_size * #5852 Make set_chunk_time_interval CAggs aware * #5868 Allow ALTER TABLE ... REPLICA IDENTITY (FULL|INDEX) on materialized hypertables (continuous aggregates) * #5875 Add job exit status and runtime to log * #5909 CREATE INDEX ONLY ON hypertable creates index on chunks **Bugfixes** * #5860 Fix interval calculation for hierarchical CAggs * #5894 Check unique indexes when enabling compression * #5951 _timescaledb_internal.create_compressed_chunk doesn't account for existing uncompressed rows * #5988 Move functions to _timescaledb_functions schema * #5788 Chunk_create must add an existing table or fail * #5872 Fix duplicates on partially compressed chunk reads * #5918 Fix crash in COPY from program returning error * #5990 Place data in first/last function in correct mctx * #5991 Call eq_func correctly in time_bucket_gapfill * #6015 Correct row count in EXPLAIN ANALYZE INSERT .. ON CONFLICT output * #6035 Fix server crash on UPDATE of compressed chunk * #6044 Fix server crash when using duplicate segmentby column * #6045 Fix segfault in set_integer_now_func * #6053 Fix approximate_row_count for CAggs * #6081 Improve compressed DML datatype handling * #6084 Propagate parameter changes to decompress child nodes * #6102 Schedule compression policy more often **Thanks** * @ajcanterbury for reporting a problem with lateral joins on compressed chunks * @alexanderlaw for reporting multiple server crashes * @lukaskirner for reporting a bug with monthly continuous aggregates * @mrksngl for reporting a bug with unusual user names * @willsbit for reporting a crash in time_bucket_gapfill
This release contains performance improvements for compressed hypertables and continuous aggregates and bug fixes since the 2.11.2 release. We recommend that you upgrade at the next available opportunity. This release moves all internal functions from the _timescaleb_internal schema into the _timescaledb_functions schema. This separates code from internal data objects and improves security by allowing more restrictive permissions for the code schema. If you are calling any of those internal functions you should adjust your code as soon as possible. This version also includes a compatibility layer that allows calling them in the old location but that layer will be removed in 2.14.0. **PostgreSQL 12 support removal announcement** Following the deprecation announcement for PostgreSQL 12 in TimescaleDB 2.10, PostgreSQL 12 is not supported starting with TimescaleDB 2.12. Currently supported PostgreSQL major versions are 13, 14 and 15. PostgreSQL 16 support will be added with a following TimescaleDB release. **Features** * #5137 Insert into index during chunk compression * #5150 MERGE support on hypertables * #5515 Make hypertables support replica identity * #5586 Index scan support during UPDATE/DELETE on compressed hypertables * #5596 Support for partial aggregations at chunk level * #5599 Enable ChunkAppend for partially compressed chunks * #5655 Improve the number of parallel workers for decompression * #5758 Enable altering job schedule type through `alter_job` * #5805 Make logrepl markers for (partial) decompressions * #5809 Relax invalidation threshold table-level lock to row-level when refreshing a Continuous Aggregate * #5839 Support CAgg names in chunk_detailed_size * #5852 Make set_chunk_time_interval CAggs aware * #5868 Allow ALTER TABLE ... REPLICA IDENTITY (FULL|INDEX) on materialized hypertables (continuous aggregates) * #5875 Add job exit status and runtime to log * #5909 CREATE INDEX ONLY ON hypertable creates index on chunks **Bugfixes** * #5860 Fix interval calculation for hierarchical CAggs * #5894 Check unique indexes when enabling compression * #5951 _timescaledb_internal.create_compressed_chunk doesn't account for existing uncompressed rows * #5988 Move functions to _timescaledb_functions schema * #5788 Chunk_create must add an existing table or fail * #5872 Fix duplicates on partially compressed chunk reads * #5918 Fix crash in COPY from program returning error * #5990 Place data in first/last function in correct mctx * #5991 Call eq_func correctly in time_bucket_gapfill * #6015 Correct row count in EXPLAIN ANALYZE INSERT .. ON CONFLICT output * #6035 Fix server crash on UPDATE of compressed chunk * #6044 Fix server crash when using duplicate segmentby column * #6045 Fix segfault in set_integer_now_func * #6053 Fix approximate_row_count for CAggs * #6081 Improve compressed DML datatype handling * #6084 Propagate parameter changes to decompress child nodes * #6102 Schedule compression policy more often **Thanks** * @ajcanterbury for reporting a problem with lateral joins on compressed chunks * @alexanderlaw for reporting multiple server crashes * @lukaskirner for reporting a bug with monthly continuous aggregates * @mrksngl for reporting a bug with unusual user names * @willsbit for reporting a crash in time_bucket_gapfill
When two CAggs on the same hypertable are refreshed at the same type, we had a race condition on the invalidation threshold table occur. So far, the table has been locked with a non-self-conflicting lock. Therefore, both scanners ran at the same time, but only one was able to lock the threshold value with a proper tuple lock. The other scanner ignored this failing lock and just returned. Therefore, the field computed_invalidation_threshold was never populated and still contains 0. So, invalidation_threshold_set_or_get returns and refresh end interval of 0. As a consequence, the `if (refresh_window.start >= refresh_window.end)` branch in continuous_agg_refresh_internal could be taken and we return from the refresh without doing any work. This patch adds proper error reporting and also implements some retry logic to avoid these problems. A self-conficting lock is not used due to the problems discussed in timescale#5809.
When two CAggs on the same hypertable are refreshed at the same type, we had a race condition on the invalidation threshold table occur. So far, the table has been locked with a non-self-conflicting lock. Therefore, both scanners ran at the same time, but only one was able to lock the threshold value with a proper tuple lock. The other scanner ignored this failing lock and just returned. Therefore, the field computed_invalidation_threshold was never populated and still contains 0. So, invalidation_threshold_set_or_get returns and refresh end interval of 0. As a consequence, the `if (refresh_window.start >= refresh_window.end)` branch in continuous_agg_refresh_internal could be taken and we return from the refresh without doing any work. This patch adds proper error reporting and also implements some retry logic to avoid these problems. A self-conficting lock is not used due to the problems discussed in #5809.
When two CAggs on the same hypertable are refreshed at the same type, we had a race condition on the invalidation threshold table occur. So far, the table has been locked with a non-self-conflicting lock. Therefore, both scanners ran at the same time, but only one was able to lock the threshold value with a proper tuple lock. The other scanner ignored this failing lock and just returned. Therefore, the field computed_invalidation_threshold was never populated and still contains 0. So, invalidation_threshold_set_or_get returns and refresh end interval of 0. As a consequence, the `if (refresh_window.start >= refresh_window.end)` branch in continuous_agg_refresh_internal could be taken and we return from the refresh without doing any work. This patch adds proper error reporting and also implements some retry logic to avoid these problems. A self-conficting lock is not used due to the problems discussed in #5809. (cherry picked from commit ac97c56)
When two CAggs on the same hypertable are refreshed at the same type, we had a race condition on the invalidation threshold table occur. So far, the table has been locked with a non-self-conflicting lock. Therefore, both scanners ran at the same time, but only one was able to lock the threshold value with a proper tuple lock. The other scanner ignored this failing lock and just returned. Therefore, the field computed_invalidation_threshold was never populated and still contains 0. So, invalidation_threshold_set_or_get returns and refresh end interval of 0. As a consequence, the `if (refresh_window.start >= refresh_window.end)` branch in continuous_agg_refresh_internal could be taken and we return from the refresh without doing any work. This patch adds proper error reporting and also implements some retry logic to avoid these problems. A self-conficting lock is not used due to the problems discussed in #5809. (cherry picked from commit ac97c56)
When refreshing a Continuous Aggregate we take a table lock on
_timescaledb_catalog.continuous_aggs_invalidation_threshold when
processing the invalidation logs (the first transaction of the refresh
Continuous Aggregate procedure). It means that even two different
Continuous Aggregates over two different hypertables will wait each
other in the first phase of the refreshing procedure. Also it lead to
problems when a pg_dump is running because it take an AccessShareLock on
tables so Continuous Aggregate refresh execution will wait until the
pg_dump finish.
Improved it by relaxing the strong table-level lock to a row-level lock
so now the Continuous Aggregate refresh procedure can be executed in
multiple sessions with less locks.
Fix #3554