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pgsql: Fix infinite wait when reading a partially written WAL record 7+ messages / 1 participants [nested] [flat]
* pgsql: Fix infinite wait when reading a partially written WAL record @ 2025-07-19 12:45 Alexander Korotkov <akorotkov@postgresql.org> 0 siblings, 0 replies; 7+ messages in thread From: Alexander Korotkov @ 2025-07-19 12:45 UTC (permalink / raw) To: pgsql-committers@lists.postgresql.org Fix infinite wait when reading a partially written WAL record If a crash occurs while writing a WAL record that spans multiple pages, the recovery process marks the page with the XLP_FIRST_IS_OVERWRITE_CONTRECORD flag. However, logical decoding currently attempts to read the full WAL record based on its expected size before checking this flag, which can lead to an infinite wait if the remaining data is never written (e.g., no activity after crash). This patch updates the logic first to read the page header and check for the XLP_FIRST_IS_OVERWRITE_CONTRECORD flag before attempting to reconstruct the full WAL record. If the flag is set, decoding correctly identifies the record as incomplete and avoids waiting for WAL data that will never arrive. Discussion: https://postgr.es/m/CAAKRu_ZCOzQpEumLFgG_%2Biw3FTa%2BhJ4SRpxzaQBYxxM_ZAzWcA%40mail.gmail.com Discussion: https://postgr.es/m/CALDaNm34m36PDHzsU_GdcNXU0gLTfFY5rzh9GSQv%3Dw6B%2BQVNRQ%40mail.gmail.com Author: Vignesh C <vignesh21@gmail.com> Reviewed-by: Hayato Kuroda <kuroda.hayato@fujitsu.com> Reviewed-by: Dilip Kumar <dilipbalaut@gmail.com> Reviewed-by: Michael Paquier <michael@paquier.xyz> Reviewed-by: Alexander Korotkov <aekorotkov@gmail.com> Backpatch-through: 13 Branch ------ master Details ------- https://git.postgresql.org/pg/commitdiff/d3917d8f13e725a3ae3be8a1c051e677ac6e3334 Modified Files -------------- src/backend/access/transam/xlogreader.c | 20 +++++++++++++++----- 1 file changed, 15 insertions(+), 5 deletions(-) ^ permalink raw reply [nested|flat] 7+ messages in thread
* pgsql: Fix infinite wait when reading a partially written WAL record @ 2025-07-19 12:45 Alexander Korotkov <akorotkov@postgresql.org> 0 siblings, 0 replies; 7+ messages in thread From: Alexander Korotkov @ 2025-07-19 12:45 UTC (permalink / raw) To: pgsql-committers@lists.postgresql.org Fix infinite wait when reading a partially written WAL record If a crash occurs while writing a WAL record that spans multiple pages, the recovery process marks the page with the XLP_FIRST_IS_OVERWRITE_CONTRECORD flag. However, logical decoding currently attempts to read the full WAL record based on its expected size before checking this flag, which can lead to an infinite wait if the remaining data is never written (e.g., no activity after crash). This patch updates the logic first to read the page header and check for the XLP_FIRST_IS_OVERWRITE_CONTRECORD flag before attempting to reconstruct the full WAL record. If the flag is set, decoding correctly identifies the record as incomplete and avoids waiting for WAL data that will never arrive. Discussion: https://postgr.es/m/CAAKRu_ZCOzQpEumLFgG_%2Biw3FTa%2BhJ4SRpxzaQBYxxM_ZAzWcA%40mail.gmail.com Discussion: https://postgr.es/m/CALDaNm34m36PDHzsU_GdcNXU0gLTfFY5rzh9GSQv%3Dw6B%2BQVNRQ%40mail.gmail.com Author: Vignesh C <vignesh21@gmail.com> Reviewed-by: Hayato Kuroda <kuroda.hayato@fujitsu.com> Reviewed-by: Dilip Kumar <dilipbalaut@gmail.com> Reviewed-by: Michael Paquier <michael@paquier.xyz> Reviewed-by: Alexander Korotkov <aekorotkov@gmail.com> Backpatch-through: 13 Branch ------ REL_18_STABLE Details ------- https://git.postgresql.org/pg/commitdiff/5449d5b7ae9c2355ce200253874b966e90392d81 Modified Files -------------- src/backend/access/transam/xlogreader.c | 20 +++++++++++++++----- 1 file changed, 15 insertions(+), 5 deletions(-) ^ permalink raw reply [nested|flat] 7+ messages in thread
* pgsql: Fix infinite wait when reading a partially written WAL record @ 2025-07-19 12:45 Alexander Korotkov <akorotkov@postgresql.org> 0 siblings, 0 replies; 7+ messages in thread From: Alexander Korotkov @ 2025-07-19 12:45 UTC (permalink / raw) To: pgsql-committers@lists.postgresql.org Fix infinite wait when reading a partially written WAL record If a crash occurs while writing a WAL record that spans multiple pages, the recovery process marks the page with the XLP_FIRST_IS_OVERWRITE_CONTRECORD flag. However, logical decoding currently attempts to read the full WAL record based on its expected size before checking this flag, which can lead to an infinite wait if the remaining data is never written (e.g., no activity after crash). This patch updates the logic first to read the page header and check for the XLP_FIRST_IS_OVERWRITE_CONTRECORD flag before attempting to reconstruct the full WAL record. If the flag is set, decoding correctly identifies the record as incomplete and avoids waiting for WAL data that will never arrive. Discussion: https://postgr.es/m/CAAKRu_ZCOzQpEumLFgG_%2Biw3FTa%2BhJ4SRpxzaQBYxxM_ZAzWcA%40mail.gmail.com Discussion: https://postgr.es/m/CALDaNm34m36PDHzsU_GdcNXU0gLTfFY5rzh9GSQv%3Dw6B%2BQVNRQ%40mail.gmail.com Author: Vignesh C <vignesh21@gmail.com> Reviewed-by: Hayato Kuroda <kuroda.hayato@fujitsu.com> Reviewed-by: Dilip Kumar <dilipbalaut@gmail.com> Reviewed-by: Michael Paquier <michael@paquier.xyz> Reviewed-by: Alexander Korotkov <aekorotkov@gmail.com> Backpatch-through: 13 Branch ------ REL_16_STABLE Details ------- https://git.postgresql.org/pg/commitdiff/b485e1c89a6dd210518eb4e26427df64831cf394 Modified Files -------------- src/backend/access/transam/xlogreader.c | 20 +++++++++++++++----- 1 file changed, 15 insertions(+), 5 deletions(-) ^ permalink raw reply [nested|flat] 7+ messages in thread
* pgsql: Fix infinite wait when reading a partially written WAL record @ 2025-07-19 12:45 Alexander Korotkov <akorotkov@postgresql.org> 0 siblings, 0 replies; 7+ messages in thread From: Alexander Korotkov @ 2025-07-19 12:45 UTC (permalink / raw) To: pgsql-committers@lists.postgresql.org Fix infinite wait when reading a partially written WAL record If a crash occurs while writing a WAL record that spans multiple pages, the recovery process marks the page with the XLP_FIRST_IS_OVERWRITE_CONTRECORD flag. However, logical decoding currently attempts to read the full WAL record based on its expected size before checking this flag, which can lead to an infinite wait if the remaining data is never written (e.g., no activity after crash). This patch updates the logic first to read the page header and check for the XLP_FIRST_IS_OVERWRITE_CONTRECORD flag before attempting to reconstruct the full WAL record. If the flag is set, decoding correctly identifies the record as incomplete and avoids waiting for WAL data that will never arrive. Discussion: https://postgr.es/m/CAAKRu_ZCOzQpEumLFgG_%2Biw3FTa%2BhJ4SRpxzaQBYxxM_ZAzWcA%40mail.gmail.com Discussion: https://postgr.es/m/CALDaNm34m36PDHzsU_GdcNXU0gLTfFY5rzh9GSQv%3Dw6B%2BQVNRQ%40mail.gmail.com Author: Vignesh C <vignesh21@gmail.com> Reviewed-by: Hayato Kuroda <kuroda.hayato@fujitsu.com> Reviewed-by: Dilip Kumar <dilipbalaut@gmail.com> Reviewed-by: Michael Paquier <michael@paquier.xyz> Reviewed-by: Alexander Korotkov <aekorotkov@gmail.com> Backpatch-through: 13 Branch ------ REL_15_STABLE Details ------- https://git.postgresql.org/pg/commitdiff/9f270f48f3fed358d62e13ec8c090124d47d86a0 Modified Files -------------- src/backend/access/transam/xlogreader.c | 20 +++++++++++++++----- 1 file changed, 15 insertions(+), 5 deletions(-) ^ permalink raw reply [nested|flat] 7+ messages in thread
* pgsql: Fix infinite wait when reading a partially written WAL record @ 2025-07-19 12:46 Alexander Korotkov <akorotkov@postgresql.org> 0 siblings, 0 replies; 7+ messages in thread From: Alexander Korotkov @ 2025-07-19 12:46 UTC (permalink / raw) To: pgsql-committers@lists.postgresql.org Fix infinite wait when reading a partially written WAL record If a crash occurs while writing a WAL record that spans multiple pages, the recovery process marks the page with the XLP_FIRST_IS_OVERWRITE_CONTRECORD flag. However, logical decoding currently attempts to read the full WAL record based on its expected size before checking this flag, which can lead to an infinite wait if the remaining data is never written (e.g., no activity after crash). This patch updates the logic first to read the page header and check for the XLP_FIRST_IS_OVERWRITE_CONTRECORD flag before attempting to reconstruct the full WAL record. If the flag is set, decoding correctly identifies the record as incomplete and avoids waiting for WAL data that will never arrive. Discussion: https://postgr.es/m/CAAKRu_ZCOzQpEumLFgG_%2Biw3FTa%2BhJ4SRpxzaQBYxxM_ZAzWcA%40mail.gmail.com Discussion: https://postgr.es/m/CALDaNm34m36PDHzsU_GdcNXU0gLTfFY5rzh9GSQv%3Dw6B%2BQVNRQ%40mail.gmail.com Author: Vignesh C <vignesh21@gmail.com> Reviewed-by: Hayato Kuroda <kuroda.hayato@fujitsu.com> Reviewed-by: Dilip Kumar <dilipbalaut@gmail.com> Reviewed-by: Michael Paquier <michael@paquier.xyz> Reviewed-by: Alexander Korotkov <aekorotkov@gmail.com> Backpatch-through: 13 Branch ------ REL_13_STABLE Details ------- https://git.postgresql.org/pg/commitdiff/762f352ca4a6c7007f1c32b0d4e4fbeb8c807468 Modified Files -------------- src/backend/access/transam/xlogreader.c | 18 +++++++++++++----- 1 file changed, 13 insertions(+), 5 deletions(-) ^ permalink raw reply [nested|flat] 7+ messages in thread
* pgsql: Fix infinite wait when reading a partially written WAL record @ 2025-07-19 12:46 Alexander Korotkov <akorotkov@postgresql.org> 0 siblings, 0 replies; 7+ messages in thread From: Alexander Korotkov @ 2025-07-19 12:46 UTC (permalink / raw) To: pgsql-committers@lists.postgresql.org Fix infinite wait when reading a partially written WAL record If a crash occurs while writing a WAL record that spans multiple pages, the recovery process marks the page with the XLP_FIRST_IS_OVERWRITE_CONTRECORD flag. However, logical decoding currently attempts to read the full WAL record based on its expected size before checking this flag, which can lead to an infinite wait if the remaining data is never written (e.g., no activity after crash). This patch updates the logic first to read the page header and check for the XLP_FIRST_IS_OVERWRITE_CONTRECORD flag before attempting to reconstruct the full WAL record. If the flag is set, decoding correctly identifies the record as incomplete and avoids waiting for WAL data that will never arrive. Discussion: https://postgr.es/m/CAAKRu_ZCOzQpEumLFgG_%2Biw3FTa%2BhJ4SRpxzaQBYxxM_ZAzWcA%40mail.gmail.com Discussion: https://postgr.es/m/CALDaNm34m36PDHzsU_GdcNXU0gLTfFY5rzh9GSQv%3Dw6B%2BQVNRQ%40mail.gmail.com Author: Vignesh C <vignesh21@gmail.com> Reviewed-by: Hayato Kuroda <kuroda.hayato@fujitsu.com> Reviewed-by: Dilip Kumar <dilipbalaut@gmail.com> Reviewed-by: Michael Paquier <michael@paquier.xyz> Reviewed-by: Alexander Korotkov <aekorotkov@gmail.com> Backpatch-through: 13 Branch ------ REL_14_STABLE Details ------- https://git.postgresql.org/pg/commitdiff/bedfdb85b0a344c84b04c234339075d676b7b608 Modified Files -------------- src/backend/access/transam/xlogreader.c | 18 +++++++++++++----- 1 file changed, 13 insertions(+), 5 deletions(-) ^ permalink raw reply [nested|flat] 7+ messages in thread
* pgsql: Fix infinite wait when reading a partially written WAL record @ 2025-07-19 22:34 Alexander Korotkov <akorotkov@postgresql.org> 0 siblings, 0 replies; 7+ messages in thread From: Alexander Korotkov @ 2025-07-19 22:34 UTC (permalink / raw) To: pgsql-committers@lists.postgresql.org Fix infinite wait when reading a partially written WAL record If a crash occurs while writing a WAL record that spans multiple pages, the recovery process marks the page with the XLP_FIRST_IS_OVERWRITE_CONTRECORD flag. However, logical decoding currently attempts to read the full WAL record based on its expected size before checking this flag, which can lead to an infinite wait if the remaining data is never written (e.g., no activity after crash). This patch updates the logic first to read the page header and check for the XLP_FIRST_IS_OVERWRITE_CONTRECORD flag before attempting to reconstruct the full WAL record. If the flag is set, decoding correctly identifies the record as incomplete and avoids waiting for WAL data that will never arrive. Discussion: https://postgr.es/m/CAAKRu_ZCOzQpEumLFgG_%2Biw3FTa%2BhJ4SRpxzaQBYxxM_ZAzWcA%40mail.gmail.com Discussion: https://postgr.es/m/CALDaNm34m36PDHzsU_GdcNXU0gLTfFY5rzh9GSQv%3Dw6B%2BQVNRQ%40mail.gmail.com Author: Vignesh C <vignesh21@gmail.com> Reviewed-by: Hayato Kuroda <kuroda.hayato@fujitsu.com> Reviewed-by: Dilip Kumar <dilipbalaut@gmail.com> Reviewed-by: Michael Paquier <michael@paquier.xyz> Reviewed-by: Alexander Korotkov <aekorotkov@gmail.com> Backpatch-through: 13 Branch ------ REL_17_STABLE Details ------- https://git.postgresql.org/pg/commitdiff/c9f4e7520603836b924a218a34633f545c0173f3 Modified Files -------------- src/backend/access/transam/xlogreader.c | 20 +++++++++++++++----- 1 file changed, 15 insertions(+), 5 deletions(-) ^ permalink raw reply [nested|flat] 7+ messages in thread
end of thread, other threads:[~2025-07-19 22:34 UTC | newest] Thread overview: 7+ messages (download: mbox mbox.gz follow: Atom feed) -- links below jump to the message on this page -- 2025-07-19 12:45 pgsql: Fix infinite wait when reading a partially written WAL record Alexander Korotkov <akorotkov@postgresql.org> 2025-07-19 12:45 pgsql: Fix infinite wait when reading a partially written WAL record Alexander Korotkov <akorotkov@postgresql.org> 2025-07-19 12:45 pgsql: Fix infinite wait when reading a partially written WAL record Alexander Korotkov <akorotkov@postgresql.org> 2025-07-19 12:45 pgsql: Fix infinite wait when reading a partially written WAL record Alexander Korotkov <akorotkov@postgresql.org> 2025-07-19 12:46 pgsql: Fix infinite wait when reading a partially written WAL record Alexander Korotkov <akorotkov@postgresql.org> 2025-07-19 12:46 pgsql: Fix infinite wait when reading a partially written WAL record Alexander Korotkov <akorotkov@postgresql.org> 2025-07-19 22:34 pgsql: Fix infinite wait when reading a partially written WAL record Alexander Korotkov <akorotkov@postgresql.org>
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